Re: New gas furnace/AC recommendations?
Home Guy
> I didnt know furnaces ran windows.
Don't joke. Next year they'll be running linux or android.
> Consumer Reports mag did a poll of about 22000 people years ago
> the top results were suprising
So post them here.
> If I was looking for one it would be stainless steel heat exchanger
> not treated steel.
Yes. Stainless for both the primary and secondary exchangers. Take a
magnet with you to the hvac dealer's show room and test the units they
have on display.
> Vsdc should also save you 15-30% on electric usage overall.
> The first generation untis failed within 6-10 years, ive heard
> but they redisigned the electronics so maybe they last now
Correct term for vsdc motors is ECM. ECM motors are a crock of shit.
Best you'll save is 100 watts compared to 1/4 hp AC motor, and less if
you have 2-speed AC motor. Saving 100 watts at 10 cents/kwh is about
$100 (that's 100 watts continuously for an entire year). Now subtract
the electricity used by the furnace motherboard, and various other
blowers and condensate pump. The extra 100 watts used by AC motors are
dumped into the house as heat - which is what you need in the winter
(and spring and fall depending where you live) so it's not all wasted
energy.
Lifespan of ECM motor is 1/2 to 1/4 that of AC motor, and it's 4 to 8
times more expensive (upfront cost of furnace is higher, repair costs
higher). ECM motors create EM/RFI on your household wiring, can
interfere with tv and radio reception.
Now tell me how you're saving with an ECM motor.
So where are we?
1) Adding second stage heat exchanger to conventional (70 - 80%)
furnaces from 30 years ago gives us condensing furnace (95% give or
take) - which is good. I do like that improvement.
2) Using cheap steel for heat exchangers compared to furnaces from 30
years ago is bad. Using stainless is good.
3) Using electronic ignition is bad comprimize from cost/savings point
of view compared to standing pilot light. No real need to use
electronic ignition in modern condensing furnace.
4) Using ECM motors is also bad comprimize compared to 1/4 or 1/3 hp AC
squirrel cage motor. *Actual* or *Net* energy savings don't justify
extra cost and reduced longevity.
As a consumer, give me the choice of electronic ignition or conventional
pilot. Give me the choice of ECM vs standard AC motor. Give me the
choice of mechanical thermostat (in the furnace) to control gas valve
and fan motor instead of electronic motherboard. Give me all stainless
for the exchangers. If you don't give me ALL those choices, then I say
that modern furnaces and the entire industry is a crock of shit.
Beyond the furnace itself, it's time to start ducting winter heat around
the AC coils instead of going through them. You want efficiency? It's
not efficient to blow air through coils when you don't need to do it
during the winter.
It's also time to allow for spring/fall cooling by having ducting and
gating that allows the furnace to pull return air from the outside,
force it into the house, and gate the interior return air back to the
outside. When ever you want the house cooler, and the outside air is
cooler than the inside air, then why use your AC when you can draw
outside air into the house directly?
Steve
"Home Guy" <Ho...@Guy.com> wrote in message news:4CFBC71A...@Guy.com...
> ransley wrote:
>
>> I didnt know furnaces ran windows.
>
> Don't joke. Next year they'll be running linux or android.
The new high end systems are serial control with variable frequency inverter
drives that will vary their output from 40% - 115% of their rated capacity.
>> Consumer Reports mag did a poll of about 22000 people years ago
>> the top results were suprising
>
> So post them here.
>> If I was looking for one it would be stainless steel heat exchanger
>> not treated steel.
Look for tubular primary heat exchanger, not "clam shell".
> Yes. Stainless for both the primary and secondary exchangers. Take a
> magnet with you to the hvac dealer's show room and test the units they
> have on display.
If the furnace is correctly sized, properly installed and adjusted,
aluminized steel or stainless.... either will give you a good service life.
>> Vsdc should also save you 15-30% on electric usage overall.
>> The first generation untis failed within 6-10 years, ive heard
>> but they redisigned the electronics so maybe they last now
90% of those failures were due to incorrectly designed and sized ductwork
that caused extreme static pressures.
> Correct term for vsdc motors is ECM. ECM motors are a crock of shit.
> Best you'll save is 100 watts compared to 1/4 hp AC motor, and less if
> you have 2-speed AC motor. Saving 100 watts at 10 cents/kwh is about
> $100 (that's 100 watts continuously for an entire year). Now subtract
> the electricity used by the furnace motherboard, and various other
> blowers and condensate pump. The extra 100 watts used by AC motors are
> dumped into the house as heat - which is what you need in the winter
> (and spring and fall depending where you live) so it's not all wasted
> energy.
you need to do some more homework here.
> Lifespan of ECM motor is 1/2 to 1/4 that of AC motor, and it's 4 to 8
> times more expensive (upfront cost of furnace is higher, repair costs
> higher). ECM motors create EM/RFI on your household wiring, can
> interfere with tv and radio reception.
ECM motors have the same or greater lifespan, use half the energy to run and
are a whole lot quieter than PSC motors. Only the cheapest manufactures with
the cheapest models of furnaces have issues with RFI. yes you will get what
you pay for.
> Now tell me how you're saving with an ECM motor.
The average system that I install uses 30% - 40% less energy to run.
> So where are we?
Talking about how you need to go back to school, and get up to speed with
the new systems.
> 1) Adding second stage heat exchanger to conventional (70 - 80%)
> furnaces from 30 years ago gives us condensing furnace (95% give or
> take) - which is good. I do like that improvement.
90+ furnaces VS 80+ furnaces will largely depend on location, climate, and
degree days. Here in south Mississippi, the additional cost of a 90+ furnace
is not justified, where in the northern states where they have 9 months of
winter sports is a different story.
> 2) Using cheap steel for heat exchangers compared to furnaces from 30
> years ago is bad. Using stainless is good.
Stainless is good, but also much more expensive. Will the additional cost be
worth it in your location?
Keep in mind that heating and cooling systems are not built to last forever.
> 3) Using electronic ignition is bad comprimize from cost/savings point
> of view compared to standing pilot light. No real need to use
> electronic ignition in modern condensing furnace.
Please explain how this is so?? or do you advocate removing half of the
safety devices on the furnace in favor of a standing pilot?? I don't know of
*ANY* legitmate HVAC tech that would purposly want to remove safeties from
any gas appliance.
> 4) Using ECM motors is also bad comprimize compared to 1/4 or 1/3 hp AC
> squirrel cage motor. *Actual* or *Net* energy savings don't justify
> extra cost and reduced longevity.
Please explain how you come up with this.
BTW, I installed a new 3ton, 15SEER heat pump system for a customer 2 weeks
ago, he has the ability to monitor his *ACTUAL* energy usage. The new system
uses 1500 watts less energy to run it than the old system did.
Last January I installed a new 4 ton 14SEER dual fuel/hybrid system in my
own home and it reduced my energy usage by 42% over this last year. BOTH
systems have ECM blower motors, as well as ECM condenser fan motors.
> As a consumer, give me the choice of electronic ignition or conventional
> pilot. Give me the choice of ECM vs standard AC motor. Give me the
> choice of mechanical thermostat (in the furnace) to control gas valve
> and fan motor instead of electronic motherboard. Give me all stainless
> for the exchangers. If you don't give me ALL those choices, then I say
> that modern furnaces and the entire industry is a crock of shit.
So you want to go back in time and have your energy bills doubled.....
Technology is a good thing when the contractor/installer/tech has the
training, education, and experience. to me it sounds like your not happy
because its no longer a DIY proposition, and you can't make it work
correctly. in case you haven't noticed, *EVERYTHING* has electronics in it
these days. The electronics make things safer, and more energy efficient.
FWIW, a good quality digital control can reduce your energy bills 10% - 15%
by itself, as well as increase your comfort levels by not having the 5 - 7
degree temperature swings that a mechanical thermostat will give you.
> Beyond the furnace itself, it's time to start ducting winter heat around
> the AC coils instead of going through them. You want efficiency? It's
> not efficient to blow air through coils when you don't need to do it
> during the winter.
You can't be serious
> It's also time to allow for spring/fall cooling by having ducting and
> gating that allows the furnace to pull return air from the outside,
> force it into the house, and gate the interior return air back to the
> outside. When ever you want the house cooler, and the outside air is
> cooler than the inside air, then why use your AC when you can draw
> outside air into the house directly?
The A/C does *MORE* than just cool the air... but I just don't have the time
or the inclination to explain it all to you. Its pretty obvious that your
not a tech by any stretch of the imagination.
To the OP... I would highly recommend that you call your local *COMPETENT*,
licensed, insured, professionally trained, HVAC technician to do a complete
assesment of your home to see what it actually needs, and recomendations for
a top quality installation of a top quality system that is best suited for
your home in your particular climate.
--
Steve @ Noon-Air Heating & A/C
"Stop calling me for freebies Satan,
I'll fix your air conditioner when you pay me, Cheapskate!"
ransley
I dont know how to cut and paste yet but its 2008 CR magazine furnace
survey
Ecm Vsdc, it can run at 100watts vs 375 for my 1/4hp, thats near 70%
saving in slow mode, maybe near 100w less at high speed.
Who in the US pays only 0.10c per Kwh, you must live near a big Dam
and get subsidised electric because im .18 and so is the rest of the
US, many place are near 0.25 kwh.
You miss the point, its comfort or else you wouldnt even have a
heating system. Vsdc can remove in low speed maybe 50% more moisture
with minimal cooling so its great in humid areas, great for homes with
uneven heat. It is about comfort, but can save the cost of the motor
in electric usage over 6-7 years. That was my figure years ago at .
125kwh.
You have to know yearly hours run in heat and AC and a real Kwh cost
to make any claim to it not paying back.
Lifespan, are you refering to the old or new redesign motor.
Electronic ignitions failing, so do thermocuples.
Home Guy
> If the furnace is correctly sized, properly installed and
> adjusted,
How exactly do you improperly install a furnace?
If you are replacing an existing furnace, one that has been running for
years in a given house and presumably giving satisfactory service, then
how possible can you remove it and "improperly" install a new one in
it's place?
What is meant by improper? That a water line is connected to the gas
input line? That the upstairs thermostat is connected to the furnace AC
power input? That the return duct and output air plenum are connected
backwards?
> aluminized steel or stainless....
> either will give you a good service life.
How does the correct sizing of a furnace impact on whether or not the
heat exchanger lifespan is impacted by being stainless steel or regular
steel?
> 90% of those (ECM motor) failures were due to incorrectly designed
> and sized ductwork that caused extreme static pressures.
Would these be the same ductwork designed and installed by licensed
contractors?
Would these be the same ductwork that was original to the homes in
question - the same ductwork that somehow didn't manage to dammage or
burn out the motor in the previous furnace - presumably an AC motor?
I'm sorry, but if my 36 year-old AC motor didn't burn out because of the
size of my existing ductwork, then it's a crock of shit that the same
ductwork is the reason why a new ECM motor burns up.
Blame the ductwork. When you have to explain to the customer why his
new $4000 furnace is costing so much repair hassles, blame the ductwork.
> > Correct term for vsdc motors is ECM. ECM motors are a crock of
> > shit. Best you'll save is 100 watts compared to 1/4 hp AC motor,
> > and less if you have 2-speed AC motor. Saving 100 watts at 10
> > cents/kwh is about $100 (that's 100 watts continuously for an
> > entire year). Now subtract the electricity used by the furnace
> > otherboard, and various other blowers and condensate pump. The
> > extra 100 watts used by AC motors are dumped into the house as
> > heat - which is what you need in the winter (and spring and fall
> > depending where you live) so it's not all wasted energy.
>
> you need to do some more homework here.
You need to show you're a man by pointing out exactly which of my
statements above are wrong.
I'm right when I say that:
1) ECM motor uses 100 less watts when running full speed compared to 1/4
hp AC motor running at full speed.
2) The extra 100 watts used by AC motor is dumped into the house as heat
during the heating months, so it isin't exactly wasted energy from the
point of view of the home owner.
3) You can't compare the energy usage of an ECM motor running 1/4 or 1/2
speed against a single-speed AC motor. If you want to compare the costs
of multi-speed operation, then you must compare ECM with a 2-speed AC
motor, and you must correctly estimate the amount of time (total hours
per year) that the fan will be running at fractional speed.
> > Lifespan of ECM motor is 1/2 to 1/4 that of AC motor, and it's
> > 4 to 8 times more expensive (upfront cost of furnace is higher,
> > repair costs higher). ECM motors create EM/RFI on your household
> > wiring, can interfere with tv and radio reception.
>
> ECM motors have the same or greater lifespan,
Totally wrong, because you have to factor in the control or drive
electronics that's powering the motor, and when you do, you'll end up
with burned out transistors.
> use half the energy to run
The efficiency of fractional horse-power ECM motors are (at best) 60%,
while a 1/4 hp PSC AC motor will have an efficiency of 40% (if running
at full speed). 1/4 horse power is about 186 watts, so an AC motor will
use about 465 watts, while an ECM motor will use 310 watts. The
difference (about 155 watts) would use 1,357 kw hours given a
continuous 1-year run time. If the total electricity cost was 15 cents
per kw hour, then that equates to $200 per year.
Now if you consider the case of a 2-speed AC motor compared with a
2-speed (or even variable-speed ECM furnace) and if you factor in that
in a typical use-case that neither motor would or could be operating for
up to 25% of the time, then the potential savings from using an ECM
motor will almost certainly drop to closer to $100 per year.
Now if you factor in that the 155 watts of extra energy being used by
the AC motor is given back to the house as heat, then you need to
determine what that equates to in terms of cubic-feet of equivalent
natural gas and subtract the cost of that amout of natural gas from your
electricty bill to get the true additional electric cost by using an AC
motor instead of an ECM motor.
While all ECM motors are capable of infinitely variable speed and can be
implimented as such by something as cheap and easy as programming code
in the controller, furnace makers charge a fortune for anything more
than simple 2-speed operation. That is another crock of shit for this
industry.
> and are a whole lot quieter than PSC motors.
I could argue that a belt-driven fan with an AC motor with bushings is
quieter than a direct-drive ECM motor with ball bearings.
> Only the cheapest manufactures with the cheapest models of
> furnaces have issues with RFI. yes you will get what
> you pay for.
Or so you think. There's no way that a home-owner (or even consumer
reports) is going to know which units put out RFI, and which units
actually give you what you pay for. Models change all the time - too
fast for independant testing and analysis to have any effect or be
useful for the buying public.
> > Now tell me how you're saving with an ECM motor.
>
> The average system that I install uses 30% - 40% less energy to run.
Which equates to 155 watts as I calculated above.
> > So where are we?
>
> Talking about how you need to go back to school, and get up to
> speed with the new systems.
Be a man and tell me where I've said anything wrong.
> > 2) Using cheap steel for heat exchangers compared to furnaces from 30
> > years ago is bad. Using stainless is good.
>
> Stainless is good, but also much more expensive. Will the additional
> cost be worth it in your location? Keep in mind that heating and
> cooling systems are not built to last forever.
We're comparing 30 - 40 year-old furnace technology with conventional
furnaces. If furnaces cost proportionately more today in terms of % of
disposable income then I should expect no less durability or longevity
compared to the older furnaces. You seem to be an appologist for the
industry by indicating that we should pay more and expect less.
> > 3) Using electronic ignition is bad comprimize from cost/savings
> > point of view compared to standing pilot light. No real need to
> > use electronic ignition in modern condensing furnace.
>
> Please explain how this is so??
Because standing pilot lights have been used for decades and have proven
themselves to be reliable, safe, simple, and cheap.
> or do you advocate removing half of the safety devices on the
> furnace in favor of a standing pilot??
The pilot light and it's thermocouple switch have proven to be an
excellent design in terms of safety, reliability and durability for
residential furnaces. Do you disagree? Do you have the balls to
disagree?
> I don't know of *ANY* legitmate HVAC tech that would purposly want
> to remove safeties from any gas appliance.
Removing the electronic ignition and replacing it with a pilot-light and
thermocouple does not constitute "removing a safety" device. Get a grip
here.
> > 4) Using ECM motors is also bad comprimize compared to 1/4 or
> > 1/3 hp AC squirrel cage motor. *Actual* or *Net* energy savings
> > don't justify extra cost and reduced longevity.
>
> Please explain how you come up with this.
See above. Best case savings is $200 a year, typical savings will
almost certainly be less than $100 a year.
Anyone who lives in a climate zone where they expect to use their
furnace at least 5 months out of the year will realize less than $100
savings in their combined electric and gas bill just by having a furnace
with an ECM motor. Anyone who lives in a more temperate climate zone
and runs their fan more often either alone or in conjunction with their
A/C unit will come closer to the $200 in electricity savings.
> BTW, I installed a new 3ton, 15SEER heat pump system for a customer
We're talking simply about ECM motors replacing conventional PSC AC fan
motors in residential furnaces. Motors that are part of other
components (heat pumps, A/C compressors, dishwashers, clothes washers,
dryers, etc) are another matter and have different cost/benefit
arguments.
> > As a consumer, give me the choice of (...)
> So you want to go back in time and have your energy bills doubled..
The single largest decrease in my energy bill that the furnace industry
can give me compared to what I have now comes from the 2-stage
condensing heat exchanger. Better airflow design, thinner materials,
stainless, possibly better burner design, etc. All of that comes from
better thermodynamics and materials - NOT ELECTRONICS.
The addition of electronics - particularly the electronic ignition and
ECM fan motor, adds unnecessary cost and complication to the modern
furnace with no tangible benefit to the home-owner and comes with
additional medium to long-term cost of ownership costs and device
down-time caused by component failure.
> Technology is a good thing when the contractor/installer/tech
> has the training, education, and experience
Screw the contractor. I want a box that will sit there and work year
after year. It's no consolation to me that a repair tech is just a
phone call away. I'll take reliability and durability any day over
repairability. Especially when it comes with lower up-front costs (no
electronics). And in this case, I'm not even sacrificing
repairability. Low tech = high repairability.
> to me it sounds like your not happy because its no longer
> a DIY proposition, and you can't make it work correctly.
I can install myself any furnace. That's not the point. I'm just
bitching about they choices that furnace makers are making when they
design / build them.
> in case you haven't noticed, *EVERYTHING* has electronics
> in it these days. The electronics make things safer, and
> more energy efficient.
When you have electronic ignition, you HAVE TO HAVE an array of
electronic sensors to make it safe. Having those sensors and
electronics comes with a price - a hit to cost, durability, reliability.
When you have a standing pilot light with electro-mechanical
thermocouple and gas valve, you don't need sensors or electronics,
because it's inherently safe.
> FWIW, a good quality digital control can reduce your energy bills
We're not talking about the thermost here. I can have the most
advanced, computer-controlled thermostat I want upstairs to control my
35 year-old furnace, yet still have no electronics *in* my furnace.
Understand the difference?
.p.jm.@see_my_sig_for_address.com
>Steve wrote:
>
>> If the furnace is correctly sized, properly installed and
>> adjusted,
>
>How exactly do you improperly install a furnace?
>
>If you are replacing an existing furnace, one that has been running for
>years in a given house and presumably giving satisfactory service, then
>how possible can you remove it and "improperly" install a new one in
>it's place?
You're pretty much fucking clueless, huh ? Why are you
flapping your mouth on a subject you know nothing about ?
Do you use the same 'logic' when it comes to a brake job on
your car ? 'Well, I'm just replacing the braking system that was
already there with a different master cylinder, lines, calipers, and
pads that I picked out of a catalog, from a whole different design
generation and manufacturer, so there's no way to get it
wrong, because I'm not changing the rotors ' ?
>What is meant by improper? That a water line is connected to the gas
>input line? That the upstairs thermostat is connected to the furnace AC
>power input? That the return duct and output air plenum are connected
>backwards?
That an asshole like you fucked with it. And I've seen ALL of
those things done by home-moaners, and much much more /worse.
( snipped the rest of your long-winded ignorant bullshit )
--
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Daniel who wants to know
> Steve wrote:
>
I will interject my $.02 here...
> How exactly do you improperly install a furnace?
By having too high of a TESP (total external static pressure.
>
> If you are replacing an existing furnace, one that has been running for
> years in a given house and presumably giving satisfactory service, then
> how possible can you remove it and "improperly" install a new one in
> it's place?
>
Older furnaces had a lower CFM rating, hence they have a higher temp rise
for a given output BTU rating. Newer equipment for effeciency's sake have
thinner heat exchangers (less metal thickness to push the heat through) that
can't tolerate the heat without cracking hence they have a higher CFM
rating, hence more TESP by trying to shove more CFM through the existing
ductwork.
> Would these be the same ductwork designed and installed by licensed
> contractors?
>
Sometimes, just go to the hvac-talk.com wall of shame and see all the bad
ductwork installations, many being a "ductopus" using flex duct.
> Would these be the same ductwork that was original to the homes in
> question - the same ductwork that somehow didn't manage to dammage or
> burn out the motor in the previous furnace - presumably an AC motor?
Yes, and here is why. Your average PSC or split-phase induction blower
motor on high runs at a fairly constant speed (a 4 pole motor can only speed
up from its rated speed, usually 1725 RPM to just under 1800 RPM @ 60Hz).
With a centrifugal blower (squirrel cage) the torque load on the motor is
directly controlled by the amount of air flowing through it (ande vice
versa), hence as you restrict the airflow (increase the SP) say with
undersized ductwork the blower unloads. Less torque at the same speed means
less HP (HP=torque in ft-lbs x RPM / 5252) hence less motor watts. An
underloaded motor is less effecient but lasts longer. Too little TESP on a
system with an induction motor can actually overload the motor, hence why
old systems that had belt drive blowers usually has a variable pitch sheave
on the motor. The belt ratio hence wheel speed was adjusted to run the
motor at full load with a new system. As the ductwork and/or filter got
dirty the TESP went up and the motor unloaded some.
Now here is where it gets tricky, ECMs as used on indoor blowers are
constant torque NOT constant speed. The shaft torque is held constant hence
the airflow is held mostly constant. Increase the TESP on these systems and
the blower speeds up either till the torque/airflow goes back to rated or
till the motor hits its top speed limit. More RPM X same torque / 5252 =
More HP = more watts. More watts x same airflow means hotter electronics
hence shorter life. Add in a plugged filter and the poor little motor runs
its little heart out at max speed with little cooling airflow till it burns
up.
> I'm sorry, but if my 36 year-old AC motor didn't burn out because of the
> size of my existing ductwork, then it's a crock of shit that the same
> ductwork is the reason why a new ECM motor burns up.
Explained above.
> Blame the ductwork. When you have to explain to the customer why his
> new $4000 furnace is costing so much repair hassles, blame the ductwork.
>
>
> You need to show you're a man by pointing out exactly which of my
> statements above are wrong.
>
> I'm right when I say that:
>
> 1) ECM motor uses 100 less watts when running full speed compared to 1/4
> hp AC motor running at full speed.
As said this depends on TESP. At high TESP the ECM can use more watts than
the PSC.
> 2) The extra 100 watts used by AC motor is dumped into the house as heat
> during the heating months, so it isin't exactly wasted energy from the
> point of view of the home owner.
Electric resistance heat is usually more expensive than gas heat and in the
summer it is just more sensible heat load on the evaporator hence more watts
still loses.
tra...@optonline.net
> "Home Guy" <H...@Guy.com> wrote in messagenews:4CFD0178...@Guy.com...
A while back I came across a study done on the savings of ECM blowers
in residential HVAC
applications segmented by geographic regions/climates. One key result
of that study, which
I didn't expect and I believe is reflected in what you say, is that
how much energy one saves
depends to a large extent on the duct work. The greatest savings came
from ideal
duct work, ie lowest pressure. Next was good duct work, which also
used significantly
less savings. Duct work they classified as typical still got
savings, but much more modest,
maybe 15- 20% in electricity cost. However if you have poor ducting
there can be no savings
or even a net loss of up to I think about 10%. The energy savings
also obviously depends on the climate.
But I think HomeGuy has a vaild point, at least to some extent.
Whether you can recover enough
in energy savings on an ECM versus the increased upfront cost as well
as the real potential for
higher repair bills is questionable. I've seen horror stories here
of the ECM electronics fried
by power surges for example and a $600 bill But I've never heard of
a conventional furnace blower
failing from a power surge. Also, I think you'd agree that if
improper duct sizing can screw it an cause it to fail, it's entirely
possible that some contractors who don't know what they are doing will
result in the motor failing
at some point. And if that point is after the warranty is up, then
you're screwed.
>
> > I'm sorry, but if my 36 year-old AC motor didn't burn out because of the
> > size of my existing ductwork, then it's a crock of shit that the same
> > ductwork is the reason why a new ECM motor burns up.
>
> Explained above.
>
> > Blame the ductwork. When you have to explain to the customer why his
> > new $4000 furnace is costing so much repair hassles, blame the ductwork.
>
> > You need to show you're a man by pointing out exactly which of my
> > statements above are wrong.
>
> > I'm right when I say that:
>
> > 1) ECM motor uses 100 less watts when running full speed compared to 1/4
> > hp AC motor running at full speed.
>
> As said this depends on TESP. At high TESP the ECM can use more watts than
> the PSC.
>
> > 2) The extra 100 watts used by AC motor is dumped into the house as heat
> > during the heating months, so it isin't exactly wasted energy from the
> > point of view of the home owner.
>
> Electric resistance heat is usually more expensive than gas heat and in the
> summer it is just more sensible heat load on the evaporator hence more watts
> still loses.
This same faulty logic is frequently applied to water heaters with
claims that the standby
losses from storage tank models helps heat the house. For some
reason, they completely
forget that for most of us with AC, that gain turns into a loss in the
summer.
.p.jm.@see_my_sig_for_address.com
>On Mon, 06 Dec 2010 10:30:00 -0500, Home Guy <Ho...@Guy.com> wrote:
>
>>
>>How exactly do you improperly install a furnace?
>>
>>What is meant by improper?
>>
>>That the return duct and output air plenum are connected
>>backwards?
>
>All jokes aside, I saw that once.
Not uncommon, actually. Upflow unit replaced with downflow
unit ... presto.
Gas fittings / pipe 'held together' with duct tape .....
One of my 'most memorable' discoveries long ago - Imagine a
typical kitchen from the 70's. Stainless steel sink, electric
4-burner in-counter stovetop right next to it.
Accidently touch the chrome trim around the stovetop and the
sink at the same time - get knocked on your ass.
Oh - house occupied by two old folks in their 80's.
Lift the stovetop to find - a wire burned off the burner
connector, so someone ( a PAID 'repairman' ! ) strapped it to the
OUTSIDE of the burner element with a worm clamp.
ransley
>
> - Show quoted text -- Hide quoted text -
>
> - Show quoted text -
If a power surge fried the blower it would have got the control panel
first. With any new unit you should be doubly sure its surge protected
and well grounded since you will have alot of electronics. When I got
my install they offered to somehow test my duct airflow, thats where
shopping for the right pro is important. I heard those motors were
redesigned a few years ago to separate the electronics from the heat
of the motor, since the electronics were what failed and now the motor
and design has finaly matured.
cl...@snyder.on.ca
>Steve wrote:
snip
>How exactly do you improperly install a furnace?
snip
>
>> 90% of those (ECM motor) failures were due to incorrectly designed
>> and sized ductwork that caused extreme static pressures.
>
>Would these be the same ductwork designed and installed by licensed
>contractors?
>
>Would these be the same ductwork that was original to the homes in
>question - the same ductwork that somehow didn't manage to dammage or
>burn out the motor in the previous furnace - presumably an AC motor?
It is quite possible. A belt drive blower could put up with an awfull
lot
>
>I'm sorry, but if my 36 year-old AC motor didn't burn out because of the
>size of my existing ductwork, then it's a crock of shit that the same
>ductwork is the reason why a new ECM motor burns up.
>
>Blame the ductwork. When you have to explain to the customer why his
>new $4000 furnace is costing so much repair hassles, blame the ductwork.
Not necessarily - but if the installer does not do the temperature
rize test and properly set the motor speed, you could get a failure
due to improper installation.
>
>> > Correct term for vsdc motors is ECM. ECM motors are a crock of
>> > shit. Best you'll save is 100 watts compared to 1/4 hp AC motor,
>> > and less if you have 2-speed AC motor. Saving 100 watts at 10
>> > cents/kwh is about $100 (that's 100 watts continuously for an
>> > entire year). Now subtract the electricity used by the furnace
>> > otherboard, and various other blowers and condensate pump. The
>> > extra 100 watts used by AC motors are dumped into the house as
>> > heat - which is what you need in the winter (and spring and fall
>> > depending where you live) so it's not all wasted energy.
>>
You underestimate the difference in efficiency between a standard
induction motor and an electronically commutated DC motor,
PARTICULARLY with multi-speed AC motors.
At lower speeds ECMs can save over 60% of the electricity used by PSC
motors.
For example, in low speed circulation a typical PSC furnace motor will
use 350 to 500 Watts while an ECM will use 75 - 125 W.
You need to read the entire study at:
http://www.nrc-cnrc.gc.ca/obj/irc/doc/pubs/nrcc38443/nrcc38443.pdf,
but an interesting part is the following - with the same airflow,
"The power use of the ECM and the PSC motor were measured in one-time
tests using a Nanovip power meter. The ECM used 16.5 Watts in
circulation speed and 284 W in heating speed, while the PSC motor used
350 W in circulation and 490 W in heating. Thus, the ECM used 58% as
much as the PSC motor in heating speed, but only 5% as much in
circulation. The ECM’s flow rate was almost identical to the PSC’s in
heating speed, and was 47% of the PSC’s in circulation speed."
>> you need to do some more homework here.
Ditto
>You need to show you're a man by pointing out exactly which of my
>statements above are wrong.
>
>I'm right when I say that:
>
>1) ECM motor uses 100 less watts when running full speed compared to 1/4
>hp AC motor running at full speed.
The National Research Council study quoted shows 206 watts difference
on high speed, and 330 watts less on low speed.
>
>2) The extra 100 watts used by AC motor is dumped into the house as heat
>during the heating months, so it isin't exactly wasted energy from the
>point of view of the home owner.
>
Except when running the AC - and gas is cheaper than electricity for
heating.
>3) You can't compare the energy usage of an ECM motor running 1/4 or 1/2
>speed against a single-speed AC motor. If you want to compare the costs
>of multi-speed operation, then you must compare ECM with a 2-speed AC
>motor, and you must correctly estimate the amount of time (total hours
>per year) that the fan will be running at fractional speed.
>
Or do as the National Research Council did, read the study - very
comprehensive testing.
>> > Lifespan of ECM motor is 1/2 to 1/4 that of AC motor, and it's
>> > 4 to 8 times more expensive (upfront cost of furnace is higher,
>> > repair costs higher). ECM motors create EM/RFI on your household
>> > wiring, can interfere with tv and radio reception.
>>
>> ECM motors have the same or greater lifespan,
>
>Totally wrong, because you have to factor in the control or drive
>electronics that's powering the motor, and when you do, you'll end up
>with burned out transistors.
Actually, they are finding the ECM to last at least as long as the AC
motor in many tests. (in part because they run cooler).
The motor control electronics are the least troublesom of all the
controls on modern furnaces.
SNIP
>The pilot light and it's thermocouple switch have proven to be an
>excellent design in terms of safety, reliability and durability for
>residential furnaces. Do you disagree? Do you have the balls to
>disagree?
>
I do.
I've replaced too many thermocouples on standing pilot furnaces - and
NO electonic ignitors so far on the new furnaces. Average lifespan of
my thermocouples has been less than 7 years (5 in 22 years on my own
furnace, and 5 in 7 years on my friend's gas boiler) I'm on #3 on my
water heater as well.
This is, I believe, year 8 on the electronic ignition furnace.
SNIP
>
>See above. Best case savings is $200 a year, typical savings will
>almost certainly be less than $100 a year.
>
>Anyone who lives in a climate zone where they expect to use their
>furnace at least 5 months out of the year will realize less than $100
>savings in their combined electric and gas bill just by having a furnace
>with an ECM motor. Anyone who lives in a more temperate climate zone
>and runs their fan more often either alone or in conjunction with their
>A/C unit will come closer to the $200 in electricity savings.
The blower in my furnace runs at low speed 100% of the time that the
furnace is not running on high for heat or a/c. (for air cleaner and
overall comfort)
If the furnace NEVER kicked on, the ECM saves me 2890kwh per year.
(330 watts X 24 hrs/day X 365=2890800 wh).That's $232 at $0.08 per
kwh. and that's not counting the savings when the furnace is actually
running. And the actual cost of electricity is more than $0.08/kwh
here when you add in the distribution charges and everything else, and
throw on 13% HST
>
>> BTW, I installed a new 3ton, 15SEER heat pump system for a customer
>
>We're talking simply about ECM motors replacing conventional PSC AC fan
>motors in residential furnaces. Motors that are part of other
>components (heat pumps, A/C compressors, dishwashers, clothes washers,
>dryers, etc) are another matter and have different cost/benefit
>arguments.
>
>> > As a consumer, give me the choice of (...)
>
>> So you want to go back in time and have your energy bills doubled..
>
>The single largest decrease in my energy bill that the furnace industry
>can give me compared to what I have now comes from the 2-stage
>condensing heat exchanger. Better airflow design, thinner materials,
>stainless, possibly better burner design, etc. All of that comes from
>better thermodynamics and materials - NOT ELECTRONICS.
Actually, IF the condensing furnace is 7% more efficient than the
equivalent non-condensing furnace, (97 vs 90) the fuel savings will be
about 8%. With my total annual gas bill of $700 (part of which is my
water heater) my maximum total gas savings would be less than $56 per
year.
Not a very attractive payback, particularly if I end up replacing the
secondary heat exchanger in 10 years.
>
SNIP
Home Guy
ECM motors for use in HVAC air handler systems, I've found that this
document is very informative:
http://www.buildingscience.com/documents/published-articles/pa-ecm-eficiency/at_download/file
I have pasted the conclusions of that document below. It basically says
that the benefits of ECM motors are lost in installations with high
static pressures (and something that I bet a lot of home-owners don't
want to fork out money for is to re-do the duct-work in their homes).
Perhaps someone else can explain why the flow characteristics of a duct
system is described in terms of the back-pressure it generates instead
of speaking directly about the RESISTANCE of the ductwork, even perhaps
putting a number on it (which surely can be done, given that we might
know the CFM and the air pressure at the input side of the duct, and
assuming the pressure at the far end is zero). When someone is talking
about high static pressure, they are essentially saying that the duct
system has a high resistance to flow (caused by any number of reasons -
closed or blocked vents, small-diameter ductwork, long runs of
small-size ducts, turbulence caused by right angles, filter too small or
too dense, etc).
Which could be why my idea that the gating of furnace output around the
A/C coils is not appreciated as something that can reduce airflow
resistance (ie - reduce static pressure).
As someone who's been living with and has experienced HVAC systems with
single-speed AC fan motors, I really can't appreciate the need for a
variable-speed fan motor. All this discussion about how PSC motor
efficiency drops to 15% - 30% when used at low speeds is a real mystery
to me - are there really furnaces out there that have the necessary
electronic controllers that will use PSC motors in such a variable-speed
capacity? Why no real discussion about the efficiency of 2-speed AC
motors?
I also don't understand how running a fan at low speed is better at
humidity removal when the HVAC system is in A/C mode - yet ECM makers
make that claim.
Claims that ECM motors are just as reliable as PSC are also a crock,
given that none of them could possibly be in service yet for 30 to 40
years as is the typical PSC motor to even begin such a comparison.
Youtube video showing badly-behaving ECM motors:
http://www.youtube.com/watch?v=fcdXPVZfrRk
http://www.youtube.com/watch?v=5MIgb_2LwH4&NR=1
These ECM motors look really flimsy - like the 1/8 hp electric motor I
have on my roof for my attic fan. Sorry - I wouldn't want something
that wimpy in my furnace.
Apparently they are somewhat succeptible to lighting strikes (lightning
doesn't have to hit your house directly to dammage the electronics in
your house). I guess your entire furnace is more succeptible to
lightning when it's got it's own computer. Another strike against the
modern furnace.
---------------------------------------
Conclusions:
The main conclusion that we would draw from this study is that although
the use of an ECM has the potential to reduce fan electrical power draw,
much of the benefit is lost in systems with excess static pressures. A
full analysis of this problem was done by Lawrence Berkeley national
Laboratory (Lutz et al., 2006). In other words (as in many cases in the
building industry) the benefits of high technology can be defeated by
poor design and faulty installation or implementation. Problems can
include excessively constricted duct designs and installations,
restrictive return plenum fittings, or excessively restrictive filters
(see “Is There a Downside to High-MErV Filters?” HE nov/Dec ’09, p.
32).
However, with better designs, air handler efficiencies can be
improved—significantly beyond the typical values assumed in previous
work (that is, 2.5 CFM/W or 0.4 W/CFM). This is especially true when a
given air handler is used at the lower end of its speed range. For
instance, a 1.5- to 3-ton unit being used at 2 tons air flow at 0.5 IWC
static pressure has an efficiency in the range of 3.7 CFM/W (0.27
W/CFM). Of course, reducing air flow for a given size of outdoor unit
can have negative consequences, such as reducing overall efficiency
(SEEr and EEr). But this factor can provide additional ammunition when
arguing for tighter sizing of cooling equipment, and/or two-stage
equipment with a variablespeed air handler.
In other words, if you can keep the air flows down (all other things
being equal), you are giving your ECM a better chance to achieve high
CFM/W efficiencies. The measurement of air handler efficiency is
relatively simple; it can be done mostly with gear that a home
performance contractor is likely to have. an air handler powered from an
electrical receptacle can be quickly measured with a plug-in power meter
such as a Kill-a-Watt. However, power measurements are more
time-consuming if the air handler is hard wired. But overall, increasing
the data set of installed ECM air handler efficiencies could be very
informative, as would measuring and recording the operating external
static pressures for these units.
Oscar_Lives
"Home Guy" <Ho...@Guy.com> wrote in message news:4CFD0178...@Guy.com...
> Steve wrote:
>
>> If the furnace is correctly sized, properly installed and
>> adjusted,
>
> How exactly do you improperly install a furnace?
>
> If you are replacing an existing furnace, one that has been running for
> years in a given house and presumably giving satisfactory service, then
> how possible can you remove it and "improperly" install a new one in
> it's place?
<SNIP whiny drivel>
> You need to show you're a man by pointing out exactly which of my
> statements above are wrong.
>
Come on over and I'll put my money in your mouth and you will see exactly what kind of big man I am. In fact, you will CHOKE on my manhood.
>SNIP more drivel>
> The pilot light and it's thermocouple switch have proven to be an
> excellent design in terms of safety, reliability and durability for
> residential furnaces. Do you disagree? Do you have the balls to
> disagree?
>
Come on over and feel them in your mouth.
>
> I can install myself any furnace. That's not the point. I'm just
> bitching about they choices that furnace makers are making when they
> design / build them.
You can install my very large penis in your mouth and install a very large amount of jizz in your belly.
cl...@snyder.on.ca
LOTS of furnaces and AC systems with multispeed PSC motors - and they
are terribly inneficient at low speed. And there is virtually no
"electronics" involved. On my old furnace it was just a relay - the
fan ran on low speed continually untill the furnace called for fan,
when it kicked a relay that put the power to the high speed windings
instead of the low speed.
>I also don't understand how running a fan at low speed is better at
>humidity removal when the HVAC system is in A/C mode - yet ECM makers
>make that claim.
The AC runs the fan at HIGHER speed than the furnace on my new system
- but runs the fan constantly at low speed when the AC or furnace are
not calling for circulation.
>
>Claims that ECM motors are just as reliable as PSC are also a crock,
>given that none of them could possibly be in service yet for 30 to 40
>years as is the typical PSC motor to even begin such a comparison.
>
My PSC lasted less than 20 years. It was a 1/3hp belt drive - replaced
it with a 1/2 HP
>Youtube video showing badly-behaving ECM motors:
>
>http://www.youtube.com/watch?v=fcdXPVZfrRk
>http://www.youtube.com/watch?v=5MIgb_2LwH4&NR=1
>
>These ECM motors look really flimsy - like the 1/8 hp electric motor I
>have on my roof for my attic fan. Sorry - I wouldn't want something
>that wimpy in my furnace.
Some are wimpy, some look just like a typical PSC motor - and the PSC
direct drive motors WERE wimpy - and many didn't last 10 years.
>
>Apparently they are somewhat succeptible to lighting strikes (lightning
>doesn't have to hit your house directly to dammage the electronics in
>your house). I guess your entire furnace is more succeptible to
>lightning when it's got it's own computer. Another strike against the
>modern furnace.
>
>---------------------------------------
>
>Conclusions:
>
>The main conclusion that we would draw from this study is that although
>the use of an ECM has the potential to reduce fan electrical power draw,
>much of the benefit is lost in systems with excess static pressures. A
>full analysis of this problem was done by Lawrence Berkeley national
>Laboratory (Lutz et al., 2006). In other words (as in many cases in the
>building industry) the benefits of high technology can be defeated by
>poor design and faulty installation or implementation. Problems can
>include excessively constricted duct designs and installations,
>restrictive return plenum fittings, or excessively restrictive filters
>(see “Is There a Downside to High-MErV Filters?” HE nov/Dec ’09, p.
>32).
>
IN ALL cases, the benefits of high technology can be defeated by poor
design and faulty installation - doesn't matter what field you are
looking at.
Daniel who wants to know
>
> As someone who's been living with and has experienced HVAC systems with
> single-speed AC fan motors, I really can't appreciate the need for a
> variable-speed fan motor. All this discussion about how PSC motor
> efficiency drops to 15% - 30% when used at low speeds is a real mystery
> to me - are there really furnaces out there that have the necessary
> electronic controllers that will use PSC motors in such a variable-speed
> capacity? Why no real discussion about the efficiency of 2-speed AC
> motors?
PSC blower motors are not really multispeed at all. All the extra speed taps
are are taps on what acts as an internal autotransformer. High is rated
voltage and the lower speeds just effectively undervolt the motor. Run a
typical 1050 RPM 6 pole PSC blower motor on high sometime and measure the
voltage from the low tap to neutral, it is usually around 170 volts AC
depending on the motor.
There are true 2 speed induction blower motors that are wound as both a 4
pole and a 6 pole. The high and start windings are 4 pole so the motor
always starts on high but if it is hooked up as low it switches the power
from high to low as it starts using the same centrifugal switch that cuts
off the start windings. When not running these motors will show a direct
short between the 2 speed wires.
> I also don't understand how running a fan at low speed is better at
> humidity removal when the HVAC system is in A/C mode - yet ECM makers
> make that claim.
Less airflow allows the evaporator to run colder hence it cools the air more
and the leaving air has a lower dew point hence a lower humidity % when
warmed back up by the house/building..
Steve
"Home Guy" <Ho...@Guy.com> wrote in message news:4CFDA7DE...@Guy.com...
> When it comes to discussing the pro's (or perhaps the lack thereof) of
> ECM motors for use in HVAC air handler systems, I've found that this
> document is very informative:
>
> http://www.buildingscience.com/documents/published-articles/pa-ecm-eficiency/at_download/file
>
> I have pasted the conclusions of that document below. It basically says
> that the benefits of ECM motors are lost in installations with high
> static pressures (and something that I bet a lot of home-owners don't
> want to fork out money for is to re-do the duct-work in their homes).
>
> Perhaps someone else can explain why the flow characteristics of a duct
> system is described in terms of the back-pressure it generates instead
> of speaking directly about the RESISTANCE of the ductwork, even perhaps
> putting a number on it (which surely can be done, given that we might
> know the CFM and the air pressure at the input side of the duct, and
> assuming the pressure at the far end is zero). When someone is talking
> about high static pressure, they are essentially saying that the duct
> system has a high resistance to flow (caused by any number of reasons -
> closed or blocked vents, small-diameter ductwork, long runs of
> small-size ducts, turbulence caused by right angles, filter too small or
> too dense, etc).
Exactly, and this applies to *ANY* type of blower motor
> Which could be why my idea that the gating of furnace output around the
> A/C coils is not appreciated as something that can reduce airflow
> resistance (ie - reduce static pressure).
Your idea if "gating" around the coil will cause more resistance to airflow
becaise of the right angles, and induced turbulance than just going straight
through the coil..... this is assuming that your using a coil that is
designed specificaly for that furnace (OEM).
> As someone who's been living with and has experienced HVAC systems with
> single-speed AC fan motors, I really can't appreciate the need for a
> variable-speed fan motor. All this discussion about how PSC motor
> efficiency drops to 15% - 30% when used at low speeds is a real mystery
> to me - are there really furnaces out there that have the necessary
> electronic controllers that will use PSC motors in such a variable-speed
> capacity? Why no real discussion about the efficiency of 2-speed AC
> motors?
There is no benifit with a 2 speed PSC motor, other than it has 2 speeds, as
compared to a single speed PSC motor.
> I also don't understand how running a fan at low speed is better at
> humidity removal when the HVAC system is in A/C mode - yet ECM makers
> make that claim.
It slows down the air passing the evap coil and allows more moisture to
condense on the coils to increase humidity removal.
> Claims that ECM motors are just as reliable as PSC are also a crock,
> given that none of them could possibly be in service yet for 30 to 40
> years as is the typical PSC motor to even begin such a comparison.
None of the "new" fractional horsepower motors will last 30 to 40 years
anymore, 10 - 15 years is a good lifespan. As a rule, none of them have oil
ports for lubrication, and *most* of them have sleeve bearings, not ball
bearings.
> Youtube video showing badly-behaving ECM motors:
>
> http://www.youtube.com/watch?v=fcdXPVZfrRk
> http://www.youtube.com/watch?v=5MIgb_2LwH4&NR=1
>
> These ECM motors look really flimsy - like the 1/8 hp electric motor I
> have on my roof for my attic fan. Sorry - I wouldn't want something
> that wimpy in my furnace.
You don't have a choice anymore.
> Apparently they are somewhat succeptible to lighting strikes (lightning
> doesn't have to hit your house directly to dammage the electronics in
> your house). I guess your entire furnace is more succeptible to
> lightning when it's got it's own computer. Another strike against the
> modern furnace.
Your furnace is no more succeptable to lightning or power surges than any
other appliance in your home that has a circuit board in it.
Your going to be dragged into the 21st century whether you want to or not.
Get over it
> ------------------------------------
>
> Conclusions:
>
> The main conclusion that we would draw from this study is that although
> the use of an ECM has the potential to reduce fan electrical power draw,
> much of the benefit is lost in systems with excess static pressures. A
> full analysis of this problem was done by Lawrence Berkeley national
> Laboratory (Lutz et al., 2006). In other words (as in many cases in the
> building industry) the benefits of high technology can be defeated by
> poor design and faulty installation or implementation. Problems can
> include excessively constricted duct designs and installations,
> restrictive return plenum fittings, or excessively restrictive filters
> (see "Is There a Downside to High-MErV Filters?" HE nov/Dec '09, p.
> 32).
This means that your ductwork will have to be checked for correct design and
airflow. If your too cheap to pay have it done right, then there *WILL* be
consequences, and its going to hit you right in the wallet in the form of
failures/repairs, higher utility bills, and lower comfort levels.
> However, with better designs, air handler efficiencies can be
> improved-significantly beyond the typical values assumed in previous
> work (that is, 2.5 CFM/W or 0.4 W/CFM). This is especially true when a
> given air handler is used at the lower end of its speed range. For
> instance, a 1.5- to 3-ton unit being used at 2 tons air flow at 0.5 IWC
> static pressure has an efficiency in the range of 3.7 CFM/W (0.27
> W/CFM). Of course, reducing air flow for a given size of outdoor unit
> can have negative consequences, such as reducing overall efficiency
> (SEEr and EEr). But this factor can provide additional ammunition when
> arguing for tighter sizing of cooling equipment, and/or two-stage
> equipment with a variablespeed air handler.
Your *STILL* have to have the ductwork and system sized for your home.
> In other words, if you can keep the air flows down (all other things
> being equal), you are giving your ECM a better chance to achieve high
> CFM/W efficiencies. The measurement of air handler efficiency is
> relatively simple; it can be done mostly with gear that a home
> performance contractor is likely to have. an air handler powered from an
> electrical receptacle can be quickly measured with a plug-in power meter
> such as a Kill-a-Watt. However, power measurements are more
> time-consuming if the air handler is hard wired. But overall, increasing
> the data set of installed ECM air handler efficiencies could be very
> informative, as would measuring and recording the operating external
> static pressures for these units.
This is why you need to get a *competent*, licensed, insured, professionally
trained HVAC technician to do the job. One who can and will do the
calculations, and take the measurements to insure that everything is
correctly sized and operating at peak efficiency............ or you can call
"Billy-Joe-Jim-Bob" down the road, or try to DIY. Either way, your going to
get what you paid for.
There is a reason that the very best techs do 5 - 7 semester hours a year in
continuing education and training. your not *JUST* paying for a guy with a
ticket book and a truck, unless your looking for the lowest price.
Mark
http://www.nrc-cnrc.gc.ca/obj/irc/doc/pubs/nrcc38443/nrcc38443.pdf
yes anyone interested in this subject should read that...
and take note that the study system had the blower running 100% of
the time. When the furnace was not heating, the blower ran for
circulation. and the ECM motor ran much sloer in circ mode compared
to the standard blower so there was much less circulation and not
surprisingly less energy was used.
But if you turn the blower OFF when the furnace is off like most real
people do, then it is less relevant.
and also note the part where the ECM blower caused gas consumption to
increase..
I would say the facts are presented in this paper but the writer
slanted the conclusion in favor of the ECM.
Follow the money...
Mark
ransley
Whats obvious is you are doing everything you can to put down Vsdc
motors and modern electronics for no good reason. Its future is here,
live with it.
cl...@snyder.on.ca
wrote:
>> You need to read the entire study at:
>http://www.nrc-cnrc.gc.ca/obj/irc/doc/pubs/nrcc38443/nrcc38443.pdf
>
>yes anyone interested in this subject should read that...
>
> and take note that the study system had the blower running 100% of
>the time. When the furnace was not heating, the blower ran for
>circulation. and the ECM motor ran much sloer in circ mode compared
>to the standard blower so there was much less circulation and not
>surprisingly less energy was used.
The blower speed was adjusted to provide the most efficient heat
transfer - and actually the best air flow as well. Running a squirrel
cage fan too fast can actually REDUCE circulation. I think that was
also explained in the article. That's also why restricted ducting is
such a big deal.
>
>But if you turn the blower OFF when the furnace is off like most real
>people do, then it is less relevant.
MOST people turn the blower off???
Not up here. Running the blower on low speed keeps temperatures even,
and makes the air filter a lot more effective.
>
>and also note the part where the ECM blower caused gas consumption to
>increase..
That was also explained - and I mentioned that in an earlier thread -
the higher efficiency of the blower means more gas is required - but
the cost per therm using gas is a lot lower than the cost per therm
for electric, so it is still a net saving.
>
>I would say the facts are presented in this paper but the writer
>slanted the conclusion in favor of the ECM.
>
>Follow the money...
>
In the case of the National Research Council there is no money to
follow. They are neutral, and not funded by manufacturing or marketing
companies.
>Mark
>
cl...@snyder.on.ca
wrote:
>
>
>Your going to be dragged into the 21st century whether you want to or not.
>Get over it
>
Needs to be dragged into the twentieth first, before the twenty-first
>> ------------------------------------
Steve
<cl...@snyder.on.ca> wrote in message
news:rh30g61rh1emst79s...@4ax.com...
> On Wed, 8 Dec 2010 08:35:18 -0600, "Steve" <jste...@comcast.net>
> wrote:
>
>>
>>
>>Your going to be dragged into the 21st century whether you want to or not.
>>Get over it
>>
>
> Needs to be dragged into the twentieth first, before the twenty-first
Good point.
tra...@optonline.net
> On Wed, 8 Dec 2010 10:14:48 -0800 (PST), Mark <makol...@yahoo.com>
> wrote:
>
> >> You need to read the entire study at:
> >http://www.nrc-cnrc.gc.ca/obj/irc/doc/pubs/nrcc38443/nrcc38443.pdf
>
> >yes anyone interested in this subject should read that...
>
> > and take note that the study system had the blower running 100% of
> >the time. When the furnace was not heating, the blower ran for
> >circulation. and the ECM motor ran much sloer in circ mode compared
> >to the standard blower so there was much less circulation and not
> >surprisingly less energy was used.
>
> The blower speed was adjusted to provide the most efficient heat
> transfer - and actually the best air flow as well. Running a squirrel
> cage fan too fast can actually REDUCE circulation. I think that was
> also explained in the article. That's also why restricted ducting is
> such a big deal.
>
>
>
> >But if you turn the blower OFF when the furnace is off like most real
> >people do, then it is less relevant.
>
> MOST people turn the blower off???
> Not up here. Running the blower on low speed keeps temperatures even,
> and makes the air filter a lot more effective.
I would bet 90%+ of the HVAC installed in the USA runs the blower only
when
the furnace is heating or the AC is cooling, not 24/7. In a typical
house with an
unfinished basement or crawl space, I would think running it
constantly would be
a significant waste of energy from two standpoints. One is that it
obviously uses
a lot more electricity. Second is that while circulating all that
air around you are
running it through the basement or crawlspace, attice, etc that is
unheated and
you are losing heat through the duct work on each pass.
With a properly designed system, I don't see the need for constant
circulation.
>
>
>
> >and also note the part where the ECM blower caused gas consumption to
> >increase..
>
> That was also explained - and I mentioned that in an earlier thread -
> the higher efficiency of the blower means more gas is required - but
> the cost per therm using gas is a lot lower than the cost per therm
> for electric, so it is still a net saving.
>
> >I would say the facts are presented in this paper but the writer
> >slanted the conclusion in favor of the ECM.
>
> >Follow the money...
>
> In the case of the National Research Council there is no money to
> follow. They are neutral, and not funded by manufacturing or marketing
> companies.
>
From the research I've done, I've concluded that the ECM motors are a
mixed
bag. In a typical house like mine (note that means running it only
when heating/cooling),
you might save 20% on electricity. I would pay some extra $$ for
that. However compared
to a regular motor, you have the issue of potentially higher repair
cost, ie $700 bills instead of
$100 due to the increased cost of the motor as well as the electronics
to run it.
cl...@snyder.on.ca
You don't see the need for it, but the VAST majority of new furnace
installations in ontario are set to run the blower on low, constantly.
All 3 contractors we contacted for quotes for my daughter's furnace
(multi-story condo) strongly recommended it.
Vic Smith
Strange that Canadians do that.
Maybe makes sense for that multi-story condo building.
Wouldn't make sense for my house.
Small 3-bedoom, no "zoned" heating.
Though you can "zone" by closing vents and doors to some extent.
In some situations a blower always running during heating cycle would
work that works - to distribute fireplace heat is one.
In my house the thermostat is located in the hallway adjacent to where
we spend most of our time - bedrooms, bathroom and kitchen.
The dining room and living room are cooler. Maybe a degree or 2.
And they are as big as the other rooms combined.
This suits us fine.
When we have company and are in the living room/dining room body heat
and sometimes cooking heat spilling from the kitchen keeps those rooms
comfortable.
When it's hot though I have to lower the thermostat to keep those
rooms cool.
I could reverse all that by moving the thermostat if I wanted to, but
it works how it is.
What would happen if my blower was constantly running during heating
and cooling times is this.
In winter heat would be lost through living/dining room walls and
windows, and when the A/C is running heat would be gained through the
same.
All of this come down to personal tolerance for uneven heat in
different rooms, and how much you want to pay.
There's absolutely no question that in my house a constantly running
blower would cost me both in electricity and natural gas.
Because it would move heat or cool air to places it's not needed.
I used to argue with my wife all the time about heating and cooling.
She can't take it cool in the winter, or warm in the summer.
I gave up the argument. You got to know when to fold 'em.
But I never even started an argument with the laws of thermo dynamics,
and don't intend to.
BTW, this reminds me how car A/C compressors kick in on defrost mode.
I used to pull the A/C plug when winter rolled around because I never
had a problem defrosting with just undried hot air and didn't wait to
waste a couple/few HP all winter just to blow dried air on the
windshield.
I stopped that when I heard the compressor seals could suffer from
disuse, but mostly because I lost my "need for speed."
--Vic
ransley
>
> - Show quoted text -- Hide quoted text -
>
> - Show quoted text -
On only the coldest or hottest days do I run the fan 24hr just to
balance things out. 24x7 will sure wear out a motor faster
.p.jm.@see_my_sig_for_address.com
<mark.ra...@gmail.com> wrote:
>
>On only the coldest or hottest days do I run the fan 24hr just to
>balance things out. 24x7 will sure wear out a motor faster
Actually, the worst thing for a motor is frequent starts.
cl...@snyder.on.ca
With the DC blower it's only about 100 watts to run the blower on low
in my house - a 2 story with finished basement and no doors between
floors. The house is quite well insulated, but the upstairs is still
cooler than the main floor, and the basement is very comfortable year
round.With the blower running on low constantly we do not get
condensation on the patio door on extreme cold days like we did
without the blower running, (RH is steady at about 35%)
(one register is at the corner of the door)
My daughter's place is a 6 level split, basement, entry, living room,
kitchen/dining, 2 BR and bath, and master bedroom. Built like a ruddy
silo - definitely no place for old men!!!!
We just insulated the basement and attic, and right now, with temps
down to -17, the only cool area is the entry level (built on concrete
slab - 3 outside walls)
cl...@snyder.on.ca
<mark.ra...@gmail.com> wrote:
The only motor I've had fail was the single speed belt drive. I
replaced it with the 2 speed just under half way through the life of
the furnace. The original was a 1/3HP, the replacement was 1/2 and
1/6.
The new furnace is a multispeed brushless DC motor
Home Guy
> With the DC blower it's only about 100 watts to run the blower
> on low in my house
Look - I live in Ontario too. And I just got dumped on with 3 feet of
snow, and it's like 16 to 24 F around here lately.
I live in a drafty 1976-era house. I can tell you that there is no
reason to run the blower constantly in the winter. When I switch my
HVAC from summer to winter mode, the only time my blower fan comes on is
when the furnace is on. There is just no need for a constant breeze
inside your house in the winter.
Running the fan constantly in the winter, even at a low speed, is not
efficient from a heating point of view. By keeping a constant breeze,
you're helping interior heat loss by causing interior air to constantly
come into contact with your walls and windows, which are the coolest
parts of the interior and from which heat is transfered out of your
house. When the fan is off and there's no air circulation, a
temperature gradient will set up in the air near the surface of the
walls and that air will be cold but you won't get as much heat loss
through this gradient as you would if the air was constantly mixing.
In the summer (late may to maybe late september) yes my fan is on quite
a bit, and even if I had a low-speed option I would not use it - I would
still be using the normal hi-speed mode for circulation and comfort.
And I still say that having the ability to draw return air totally from
a dedicated outside duct in the summer and force the normal return air
out of the house through another duct is more energy-efficient at
cooling your house vs using an AC during those times when the outside
air temp is lower than the current inside air temp, which frequently
happens in the late afternoon and evening in the spring and late summer.
Home Guy
> The new furnace is a multispeed brushless DC motor
Which are glorified stepper motors.
In my house, the only place these wimpy DC motors will ever be is in my
hard drive and DVD players.
Vic Smith
>
>And I still say that having the ability to draw return air totally from
>a dedicated outside duct in the summer and force the normal return air
>out of the house through another duct is more energy-efficient at
>cooling your house vs using an AC during those times when the outside
>air temp is lower than the current inside air temp, which frequently
>happens in the late afternoon and evening in the spring and late summer.
I totally agee with that.
Probably isn't done because of issues with ducting to the outside.
For my basement furnace it wold take a up window, not counting the
ductwork and diverters.
So we open the windows when it's cooler outside than in.
But if there's no breeze you really need fans in the windows to make
that work well.
--Vic
Steve
"Home Guy" <Ho...@Guy.com> wrote in message news:4D018B15...@Guy.com...
> cl...@snyder.on.ca unnecessarily full-quoted:
>
>> The new furnace is a multispeed brushless DC motor
>
> Which are glorified stepper motors.
ECM motors are *NOT* stepper motors. If you had a half a clue, you would
know this.
> In my house, the only place these wimpy DC motors will ever be is in my
> hard drive and DVD players.
Its too bad you have your mind made up and can't be confused with the facts.
If ignorance is bliss, you must be in a constant state of euphoria.
cl...@snyder.on.ca
>cl...@snyder.on.ca improperly and unnecessarily full-quoted:
>
>> With the DC blower it's only about 100 watts to run the blower
>> on low in my house
>
>Look - I live in Ontario too. And I just got dumped on with 3 feet of
>snow, and it's like 16 to 24 F around here lately.
London area? You poor guys - Waterloo Region dodged the bullet this
time!!!
>
>I live in a drafty 1976-era house. I can tell you that there is no
>reason to run the blower constantly in the winter. When I switch my
>HVAC from summer to winter mode, the only time my blower fan comes on is
>when the furnace is on. There is just no need for a constant breeze
>inside your house in the winter.
>
>Running the fan constantly in the winter, even at a low speed, is not
>efficient from a heating point of view. By keeping a constant breeze,
>you're helping interior heat loss by causing interior air to constantly
>come into contact with your walls and windows, which are the coolest
>parts of the interior and from which heat is transfered out of your
>house. When the fan is off and there's no air circulation, a
>temperature gradient will set up in the air near the surface of the
>walls and that air will be cold but you won't get as much heat loss
>through this gradient as you would if the air was constantly mixing.
You can say what you like. I heat my 1970's (1974?) 2 storey for $700
a year in Waterloo with natural gas.
>
>In the summer (late may to maybe late september) yes my fan is on quite
>a bit, and even if I had a low-speed option I would not use it - I would
>still be using the normal hi-speed mode for circulation and comfort.
Only use the AC on the really nasty hot/humid days. This last summer
that was about 2 weeks
cl...@snyder.on.ca
They are a heck of a lot more efficient than a crappy split cap
induction motor!!
tra...@optonline.net
I'd say it depends on how much cooler the outside air is. And even
then, you have
the issue of humidity which is a major concern in many climates.
Pulling humid
air from outside that happens to be 5 deg cooler than the house inside
wouldn't
seem to make a lot of sense to me. And here in the NYC area, the few
days of the
year you would do that, ie some Spring and early Fall days, it just
isn't worth it comared
to the addional ducting. Besides, I thought Home Guy was all about
simplicity. At a
minimum such a system would require actuators, more controls, etc. To
do it right
you'd have to measure outside temp, outside humidity, inside temp,
inside humidity and
then have a mircrocontroller decide what to do. Sounds exactly like
the complexity that
HG wants to rip out of a new high efficiency furnace.
If you want to go that route, a whole house fan to pull air in from
outside is an option. But
it too has the above problems and being in the upstairs ceiling/attic
interface, you now
have something difficult to seal and insulate perfectly for the entire
winter. Meaning what
you gain in a few days that you use it could be more than lost.
tra...@optonline.net
>
> - Show quoted text -
I have 57 years of service experience with conventional blower motors
that
cycle on and off with the furnace/AC and have not had one fail yet.
So,
I'd say using them only during heat or AC vs running them 24/7 is a
non-
issue in terms of longevity.
Vic Smith
You don't need microcontrollers. Just go to the basement and pull a
lever or crank on a chain fall (-:
Where I live, and the house I live in, it makes sense to draw in
outside air at night about 10-30 days a year, depending.
My house is brick, with little or no insulation.
Haven't torn off any drywall on the exterior walls, but I know from
drilling the drywall is on furring, maybe 1", not 2x4's.
Never picked up any fluff when drilling.
Surprisingly, my gas bill isn't bad.
But it can absorb a lot of heat during the days of high sun and the
heat migrates in if the nights aren't sufficiently cool.
Better to have the night air working on both sides.
Adds up to 10-30 days a year, depending.
The same was true of my last brick house.
Besides, if it's not too humid, outside air is good.
--Vic
Home Guy
> >> The new furnace is a multispeed brushless DC motor
>
> They are a heck of a lot more efficient than a crappy split cap
> induction motor!!
Sometimes durability and longevity trumps efficiency.
Even if electric heat (on a per-therm basis) is twice the cost of
natural gas, that extra energy used by a PSC motor is beneficially used
by my house in the winter, and my PSC fan is running only maybe 25 to
33% of the time, not 100% of the time. In the summer, when my fan is
running more often, it's running at full speed - something that I would
also ask an ECM motor to do, and for which the ECM motor does not have
as much of an efficiency advantage over a PSC motor.
So I'll pay the net $100 a year in additional energy cost and never have
to worry about my PSC motor failing me for several decades - if ever.
Even after gov't rebates, forking out a minimum $2000 for a new furnace
is going to take years to recover that, with the ECM motor delivering
just $100 a year and the burners / heat-exchanger *maybe* giving me an
additional $200 a year in savings. And by the time I've made those
savings the furnace will be near the end of it's reliable life-span.
Steve
<tra...@optonline.net> wrote in message
news:0d6f9a65-aa35-45a0...@s5g2000yqm.googlegroups.com...
---------------------------------------------------
Running the blower on continuous for A/C here in the deep south will
actually raise the indoor humidity, but during the winter I do ust the
"circ" function on the system control to keep the temperature mor even
between the 3 floors. The "circ" function brings on the blower for 15 - 20
minutes an hour, just to circulate the air in the house.
Steve
"Home Guy" <Ho...@Guy.com> wrote in message news:4D023E48...@Guy.com...
So your saying that the "reliable life span" of the new furnaces is only 6 -
7 years?? This may be true when installed by John Q Homeowner, or the lowest
bidder, however when correctly installed, properly adjusted, and with
correctly sized ductwork, the normal lifespan is 20 - 23 years.
You still cannot buy a new furnace today that *DOESN"T* have electronics
controling it. Furnaces with PSC motors are still available, but only in the
cheapest, lowest efficiency, "builder grade" models.
Maybe thats why your so against the new furnaces... your got the cheapest
POS furnace you could find, you got what you paid for, and now your not
happy with it.
bud--
Some systems for commercial buildings do use all outside air when
economical. They need, if I remember right, 10% outside air when
occupied in any case. Makes it more practical to go to 100%. Duct
control is with "damper motors".
They don't just use outside temperature. They likely use an "enthalpy"
controller, which combines temperature and humidity. If you don't take
in air with humidity that is too high you don't have to worry about
inside humidity, and control on temperature. One I remember had a
temperature "set point" control in the supply air duct, that was a
potentiometer output, which connected to the damper motor that
controlled the amount of outside air that came in.
--
bud--
The Daring Dufas
I've rented old buildings in the past that had an interesting hollow
tile like building block construction for the walls. The material
looks like the red roof tiles and with no heat in the warehouse area,
the temperature never got into the low 30° range, nothing ever froze.
I don't know what the material is but it seems like the designers
knew what they were doing around the turn of the last century. :-)
TDD
cl...@snyder.on.ca
Up here in Central Ontario when it is hot enough that you would want
to draw in the outside air, the humidity is way too high to make it an
acceptable alternative most days.
>
cl...@snyder.on.ca
>cl...@snyder.on.ca wrote:
>
>> >> The new furnace is a multispeed brushless DC motor
>>
>> They are a heck of a lot more efficient than a crappy split cap
>> induction motor!!
>
>Sometimes durability and longevity trumps efficiency.
What kind of motor do you think is in virtually every electric or
hybrid vehicle, and the majority of electric cycles???
ECMs are a lot less trouble prone than brushed DC motors. ONE moving
part, no open commutation, no wear, no sparks, no brushes.
>
>Even if electric heat (on a per-therm basis) is twice the cost of
>natural gas, that extra energy used by a PSC motor is beneficially used
>by my house in the winter, and my PSC fan is running only maybe 25 to
>33% of the time, not 100% of the time. In the summer, when my fan is
>running more often, it's running at full speed - something that I would
>also ask an ECM motor to do, and for which the ECM motor does not have
>as much of an efficiency advantage over a PSC motor.
Still has enough of an advantage that I wouls choose the ECM over the
PCM even if I did not choose to run the fan on low constantly.
Hey, it's your choice.
I feel I made an informed choice, and I'm more than happy with the
choice I made. You want to run with 1930's technology, that's fine
with me. I won't twist your arm.
But I also will not agree that the old stuff is always better
>
>So I'll pay the net $100 a year in additional energy cost and never have
>to worry about my PSC motor failing me for several decades - if ever.
>
>Even after gov't rebates, forking out a minimum $2000 for a new furnace
>is going to take years to recover that, with the ECM motor delivering
>just $100 a year and the burners / heat-exchanger *maybe* giving me an
>additional $200 a year in savings. And by the time I've made those
>savings the furnace will be near the end of it's reliable life-span.
That's fine as long as your old furnace lasts. I wouldn't go out and
spend $2000 (or more) for a new furnace just to get an ECM fan. But I
sure wouldn't cheap out and buy a furnace with a PSC fan motor when
the time comes to change the furnace
ransley
You keep omitting the most important reason for getting one, comfort.
It will in low speed remove near 50% more moisture. You can at low
speed run it to dehumidify with out cooling much. Great on those 70f
days when its 75 inside and real humid. it can be run by Humidistat,
just what alot of areas near water need often. Or to even out heat or
Ac in a poorly ducted house. You dont like them so dont buy one.
Home Guy
> So your saying that the "reliable life span" of the new furnaces
> is only 6 - 7 years??
What-ever they are, they're not going to last as long as the ones being
made 30 and 40 years ago - many of which are still functional even if
they've been replaced by new garbage.
> however when correctly installed, properly adjusted, and with
> correctly sized ductwork
Don't give me that "correctly installed" crap.
A furnace is a box where you connect wires and ducting and turn the
friggin thing on. It's a glorified barbeque.
Any new furnace that can't be plugged into any existing house's ductwork
and work correctly is a piece of shit.
As bad as the existing ductwork is or can be, you shouldn't have to tear
it down and re-do it just to satisfy the hyper-sensitive requirements of
a new furnace or it's delicate, wimpy ECM blower motor.
> the normal lifespan is 20 - 23 years.
Pathetic.
> You still cannot buy a new furnace today that *DOESN"T* have
> electronics controling it.
If you mean electronics *inside* it, it's that very fact that I'm
bitching about. Just because you can't buy one that doesn't have a
frakken motherboard in it doesn't mean you can't bitch and complain how
unnecessary it is to have it.
> Maybe thats why your so against the new furnaces... your got
> the cheapest POS furnace you could find,
My furnace is 36 years old and is original to the house when it was
built in 1976 which I bought 11 years ago. I have no idea where this
furnace ranked in the marketplace at the time, but obviously they made
quality stuff back then, before the industry went into the toilet in the
last 10 - 20 years.
> and now your not happy with it.
I'm very happy with it, and if I ever have to replace it, I'm going to
modify any new furnace I get by swapping it's ECM motor for a PSC one,
and remove the electronic ignition and replace it with a standing pilot,
and rip all the electronic flame and other sensors out of it, along with
the frakkin motherboard.
Home Guy
> Up here in Central Ontario when it is hot enough that you would
> want to draw in the outside air, the humidity is way too high
> to make it an acceptable alternative most days.
Down here in south-western ontario that is not usually the case.
Home Guy
> You keep omitting the most important reason for getting one,
> comfort. It will in low speed remove near 50% more moisture.
Gee, I wonder what that liquid is that runs out of a pipe coming from my
A frame above my furnace and into the floor drain beside my furnace. ?
Ever see a dehumidifier that doesn't get enough air-flow? See how much
frost accumulates on it? See how that frost doesn't melt and turn into
flowing water until you turn the unit off?
An evaporator coil that doesn't get cold enough to sweat when your
blower fan is running full speed means that you're AC unit is too small
capacity or has lost freon.
And you don't want it to get so cold that you start a frost build-up
either.
cl...@snyder.on.ca
"ON THE DAYS WHEN YOU REALLY NEED IT"
cl...@snyder.on.ca
You better start following the furnace guys around and stockpile
useable "old school" furnaces - you'll have a hell of a time modifying
the new ones to take the old parts!!
tra...@optonline.net
> "Home Guy" <H...@Guy.com> wrote in messagenews:4D023E48...@Guy.com...
I don't know what you consider "cheapest, lowest efficiency", but I'm
looking at
quotes for a Rheem 120K BTU, 95% efficient furnace that meets the govt
high
efficiency standards for the tax credit. And it has a single speed
PSC motor.
Can also get the same furnace and AC system from Trane, for $800
more.
While I don't agree with Home Guy on everything, I do agree that in
many cases
the extra cost of models with an ECM blower aren't worth it. That's
from two standpoints.
First is that those models only save on the blower electricity. And
then independent
studies have shown that you get the 40% electricity savings if the
duct work is ideal.
If it's good, you get like 25%. If it's typical it's more like 15
-20%. And if it's poor
ducting, you get 10% to -10%. So, for maybe a 15-20% savings, you
have a significantly
higher initial outlay, plus exposure to higher repair costs if the
blower motor or it's added
drive electronics fails.
I can see going with the variable ECM motor if you want to run the
blower 24/7. Or if you
highly value that it starts up quietly, can run at low speed longer to
even out heat better with
a two stage furnace on mild heating days. Or can run on slow speed
with AC to dehumidify better.
But none of those are that important to me.
>
> Maybe thats why your so against the new furnaces... your got the cheapest
> POS furnace you could find, you got what you paid for, and now your not
> happy with it.- Hide quoted text -
Home Guy
> While I don't agree with Home Guy on everything, I do agree that
> in many cases the extra cost of models with an ECM blower aren't
> worth it.
I'm guessing that it's increasingly high targets for energy efficiency
(combustion and electrical) set by gov't regulations is the reason why
we're seeing the use of ECM blower motors in consumer HVAC equipment,
just as we see the same when it comes to saftey equipment (air bags, ABS
brakes, CAFE and emissions standards) in cars. Probably the same reason
for electronic ignition vs standing pilot as well.
I can't believe that we'd see widespread use of ECM motors under true
free-market-driven conditions (ie - with no gov't efficiency mandates or
constraints).
Steve
"Home Guy" <Ho...@Guy.com> wrote in message news:4D0399DA...@Guy.com...
A lot of us don't live where they have 9 months of winter sports, and
humidity control is a huge issue. Where I am, we run A/C from March 1st
until November 1st with average summer temps of 90F with 75% to 85% RH
you can *DO* what you want, you can be as ignorant as you want....thats your
problem.
I do this for a living, and I *KNOW* first hand what the benefits of the new
systems are, and how much my customers utility bills have dropped, as well
as their comfort level increasing.
You can *TRY* to re-engineer a new furnace by taking out the electronics,
ECM motor, and electronic ignition... Just remember that as soon as you
screw with it, you have voided the warranty, as well as the UL ratings and
if you burn your house down, your insurance company will deny the claim.
Maybe you should get a job in the engineering department with the equipment
manufacturers.
The Daring Dufas
Steve, you can verify something for me because you do more of this work
than I do. I've noticed a dramatic drop in price for the ECM motors over
a period of time and I assume it's because millions of the things are
being produced now, economies of scale. I'm seeing an ECM replacement
for PSC motors offered like the Genteq EverGreen and I'm wondering if
you've converted any air handlers for customers or have considered it?
TDD
Home Guy
> I'm seeing an ECM replacement for PSC motors offered like the Genteq
> EverGreen
I think that's still made by GE
> and I'm wondering if you've converted any air handlers for
> customers or have considered it?
At least tell us what the over-the-counter (cash and carry) price is for
an ECM drop-in replacment 1/4 hp NEMA-48 1700 rpm PSC motor.
Steve
"The Daring Dufas" <the-dari...@stinky.net> wrote in message
news:ie0m4t$tcs$1...@news.eternal-september.org...
The equipment I install, already has ECM motors in it. the stuff with ECM
motors in it has a 10 year parts warranty, and the heat pumps have either a
5 year or 10 year unit replacement warranty.
I don't know why I would install an air handler with a PSC motor in it when
there is only a small difference in price for the ECM, and the PSC only has
a 5 year parts warranty, period.
Steve
"Home Guy" <Ho...@Guy.com> wrote in message news:4D03E432...@Guy.com...
They are not interchangeable.
Home Guy
>
> > I'm seeing an ECM replacement for PSC motors offered like the
> > Genteq EverGreen
> > customers or have considered it?
------------------
http://www.aosmithmotors.com/uploadedFiles/Website/Products/Distribution_HVAC-R_Motors/6850_Web_9-10.pdf
The Comfort Select FB motor is a brushless, direct current (BLDC),
permanent magnet, electronically commutated motor (ECM). The motor is
controlled by integrated electronics providing high efficiency, advanced
motor protection, and has the same performance characteristics as a PSC
motor. The Comfort Select~FB motor is designed as a direct replacement
or retrofit product for a PSC motor.
------------------
This brochure is confusing, because on the last page it lists 5
different HP sizes, while seeming to indicate the availability in only 2
HP sizes (1/2 and 1 hp) which is strange since I wouldn't think that a
residential furnace would need anything larger than 1/3 hp.
The power consumption of the 1/2 hp unit (6.3 A at 115 V) seems
excessive.
Example retail pricing:
------------------------
http://www.alpinehomeair.com/viewproduct.cfm?productID=453062575
Upgrade your furnace or air handler to a high efficiency, variable speed
blower motor without having to make complex changes to your system. The
RESCUE EcoTech™ motor drops into existing PSC (multi-speed)
induction-blower applications, without making complex wiring
modifications or changes to the system controls. Just connect the leads,
and you’re done! No 24-volt signal leads or setup required – it’s plug
and play.
With the increased efficiency and available low circulation of this
motor, you will be free to cycle air continuously without a significant
increase in utility bills. Continuous fan operation supports improved
filtration, helping to clear the air of dust and allergens – all the
while making your home more comfortable by working to reduce temperature
variations throughout the home.
The RESCUE EcoTech motor’s advanced design also features active airflow
management, which allows the motor to compensate for static pressure
changes to help maintain airflow. This means that as vents are closed or
the filter becomes full, the motor will attempt to maintain the same
airflow, helping to keep the system operating efficiently and the home
comfortable.
Standard Features
* Easy Installation - Drops into existing PSC (multi-speed) direct drive
induction-blower applications without making wiring modifications or
changes to the system controls.
* Quiet, Efficient Circulation Speed - The advanced motor design
provides a low, 600 rpm circulation speed, so you can cycle air
continuously without the noise, draft or electricity cost of a PSC
motor.
* Money Saving Efficiency - Save money on your electric bill just by
replacing the existing PSC blower motor in your furnace or air handler.
Product Specifications
Volts 115 VAC
Blower Motor Horse Power 1/2 HP
Rotational speed in revolutions per minute 1140 RPM
Number of Blower Speeds 5
Motor Warranty 2 Years
Your Price: $323.99
Emerson EcoTech Estimated Electricity Savings:
http://www.alpinehomeair.com/_viewresource.cfm?ID=2327
---------------------------
They estimate annual savings of either $38 (fan runs only during heating
or cooling) or $106 (fan runs continuously). This is for the 1/3 hp
model, based on 14 cents /kwh.
This place:
http://www.patriot-supply.com/products/showitem.cfm/196266
Also lists the 1/2 hp Emerson 5530ET motor for $323.
The Emerson 5520ET is listed as 1/3 hp by some sellers and 1/4 hp by
others. It's priced at about $300.
This is a brochure for the Fasco / Evergreen Motor:
www.fasco.com/fasco/documents/NewsletterJanuary2010.pdf
-----------------
Fasco is proud to introduce the new Evergreen motor: the world’s first
universal aftermarket Electronically Commutated Motor (ECM) specifically
designed to save energy in residential heating and cooling
applications. Like compact-fluorescent replacement bulbs now offer an
energy-saving alternative to traditional incandescent lightbulbs, the
new Evergreen motor is a new high-efficiency alternative for standard
replacement motors.
It uses proven ECM technology to save energy… and money…every time a
residential HVAC system is in use.
On average, consumers can expect to save over 25% on annual motor
operating costs – or about $60 in annual heating and cooling operation
based on 10¢/kWh. Even better, consumers can also expect to use up to
74% fewer watts with an Evergreen motor when they run their fans between
heating and
cooing cycles.
-----------------
So basically you're going to spend $300 and probably save $100 a year in
electricity if you're lucky, and probably only if you can get an actual
1/4 or 1/3 hp unit - not a 1/2 hp one.
The Daring Dufas
From looking at the information, I understand that the 1/2hp ECM motor
is the replacement for 1/3 through 1/2hp PSC motors and the 1hp ECM is
the replacement for the 3/4 through 1hp motors. The ECM motors are
adaptable according to the literature and have the programming to learn
how to operate much like an automotive engine control unit. It's very
interesting what has been done with these new motors. It reminds me of
the way switching power supplies have taken over the work once done by
less efficient shunt regulated power supplies.
TDD
Home Guy
> From looking at the information, I understand that the 1/2hp ECM
> motor is the replacement for 1/3 through 1/2hp PSC motors and the
> 1hp ECM is the replacement for the 3/4 through 1hp motors.
Would you even use a 1/2 hp ECM motor for a home furnace? You certainly
wouldn't save any money if you were replacing a 1/4 hp single-speed PSC
motor with these 1/2 hp ECM units.
> The ECM motors are adaptable according to the literature and
> have the programming to learn how to operate
How exactly do they do that?
How does a motor know how much CFM the fan is moving?
Are there pressure or flow sensors mounted in the duct work for that?
How would you use one of those replacement motors when you have an
ordinary single-speed PSC motor in a 25+ year old furnace?
Can you apply 115 vac directly to those motors to the appropriate set of
wires to make them operate - to hell with this learning crap?
I don't get this learning crap anyways. What is an ECM motor supposed
to learn? Don't you just want it to turn at a given RPM? Why all the
fuss about finessing the CFM?
If the controller can make the unit start at low RPM and then speed up,
that's great. Do it. Why worry about CFM? If the house isin't
reaching the thermostat set-point fast enough, then speed up the motor,
or turn up the burners.
To me, the feedback the motor controller should get is the difference
between actual house temperature and the thermostat set-point
temperature. The smaller that difference, the slower the motor needs to
turn and the less BTU's the furnace needs to put out. What the actual
CFM is is neither here nor there. If the occupants want to over-ride
the motor RPM to get ambient circulation, then fine, given them the
option for low and medium speed constant circulation mode based on motor
RPM - not on some sort of "learning" crap.
tra...@optonline.net
> "Home Guy" <H...@Guy.com> wrote in messagenews:4D0399DA...@Guy.com...
> > trad...@optonline.net wrote:
>
> >> While I don't agree with Home Guy on everything, I do agree that
> >> in many cases the extra cost of models with an ECM blower aren't
> >> worth it.
>
> > I'm guessing that it's increasingly high targets for energy efficiency
> > (combustion and electrical) set by gov't regulations is the reason why
> > we're seeing the use of ECM blower motors in consumer HVAC equipment,
> > just as we see the same when it comes to saftey equipment (air bags, ABS
> > brakes, CAFE and emissions standards) in cars. Probably the same reason
> > for electronic ignition vs standing pilot as well.
>
> > I can't believe that we'd see widespread use of ECM motors under true
> > free-market-driven conditions (ie - with no gov't efficiency mandates or
> > constraints).
>
> A lot of us don't live where they have 9 months of winter sports, and
> humidity control is a huge issue. Where I am, we run A/C from March 1st
> until November 1st with average summer temps of 90F with 75% to 85% RH
> you can *DO* what you want, you can be as ignorant as you want....thats your
> problem.
I'd say it's ignorant to assume everyone that's looking at a new HVAC
system
lives in the same climate that you do. I'm in coastal NJ and the
existing 26 year
old system handles the humidity just fine. If it's hot enough to be
running frequently,
no humidity problem. If it;s one of those few days where it's not hot
enough to be
running and it's getting humid inside, I lower the thermostat one
degree and in 30-45
minutes, you can feel the humidity has decreased and it's
comfortable. And that's
with an inefficient system with a single speed blower.
>
> I do this for a living, and I *KNOW* first hand what the benefits of the new
> systems are, and how much my customers utility bills have dropped, as well
> as their comfort level increasing.
My utility bills are gonna drop too when I swap out that 26 year old
system and
go to a high efficiency system with a PSC blower.
>
> You can *TRY* to re-engineer a new furnace by taking out the electronics,
> ECM motor, and electronic ignition... Just remember that as soon as you
> screw with it, you have voided the warranty, as well as the UL ratings and
> if you burn your house down, your insurance company will deny the claim.
>
> Maybe you should get a job in the engineering department with the equipment
> manufacturers.- Hide quoted text -
>
That part I agree with. But there is no need to take out an ECM
motor. You just
buy a high efficiency system that doesn't have one in it.
Steve
<tra...@optonline.net> wrote in message
news:35ea0f44-2f1c-4357...@b25g2000vbz.googlegroups.com...
---------------------------------------------
All of the high efficiency have ECM blower motors, the only ones that have
PSC blower motors are the basic, low end, 13 SEER systems..... that would be
the "spec house", and landlord specials.
>
> You can *TRY* to re-engineer a new furnace by taking out the electronics,
> ECM motor, and electronic ignition... Just remember that as soon as you
> screw with it, you have voided the warranty, as well as the UL ratings and
> if you burn your house down, your insurance company will deny the claim.
>
> Maybe you should get a job in the engineering department with the
> equipment
> manufacturers.- Hide quoted text -
>
That part I agree with. But there is no need to take out an ECM
motor. You just
buy a high efficiency system that doesn't have one in it.
You cannot get a "high" efficiency system without an ECM motor in it. Only
the basic, entry level 13 SEER systems have PSC motors in them.
FWIW, the latest technologies in residential heating and cooling systems are
using serial controlled, Variable Frequency inverter drives that literally
vary the systems output from 40% to 115% of its rated capacity depending on
demand. Even the compressor is variable speed..... This is where residential
heating cooling systems are headed. Your not going to have a choice in
refrigerants for air conditioning either.
These changes have been in the works for over 20 years.... I just gotta
wonder why a select few are bitching about it now.
k...@att.bizzzzzzzzzzzz
Switching power supplies are a replacement for many linear *series* (not
shunt) regulators. Series regulators have the active device in series with
the load. Shunt regulators have their regulating element in parallel (shunt)
with the load.
Series Regulator
(pass element) Shunt Regulator
____
| | ___
+-----+-| |-+-----+ +----+|_R_|-+--+------+
| |____| | | |/ |
/+\ | .-. /+\ Zener - .-.
(Vin) | | |Load (Vin) (Shunt) /A | |Load
\-/ === | | \-/ | | |
| GND '-' | | '-'
| | | === |
=== | === GND |
GND === GND ===
GND GND
(created by AACircuit v1.28.6 beta 04/19/05 www.tech-chat.de)
The Daring Dufas
I'm sorry, I should have written linear, I stand corrected. I've
worked on enough of the darn things. It used to be everything had
a linear regulator and heavy transformer but the power supplies
were simple and reliable. The 78xx series regulators and LM317's
make it so easy to put together a regulated supply for a project.
I was working in TV shops back in the 70's when RCA, if I recall
correctly, came out with a TV set that used the flyback transformer
as a newfangled power supply for the whole set. The company rep had
one of the new "all solid state" sets hooked to a variac transformer
which he used to run the voltage up and down. We were all impressed
by the fact that the set would show a clear but slightly shrunken
picture when the power to the set was turned down to 80 volts AC.
I knew then that things were know going to get very interesting in
the field of consumer electronics. Most of the sets we were working on
had hybrid circuitry using transistors and IC chips for low power and
low voltage then tubes for the high voltage horizontal output stage.
I remember when a horizontal output tube was under $5.00 and a
horizontal output transistor was $25.00 or more. Gasoline was also
30 cents a gallon back then. Gosh darnit! I think I'm getting old. :-)
I just had a flashback to the good old Radio Shack 12 volt DC power
supplies the company sold for powering up a car or CB radio out of
a vehicle. The early units used a TO-3 power transistor and a zener
diode as a voltage reference in the circuitry. The latter versions
used the LM317 and 78xx series regulators. I get the same power now
from a wall wort that feels so light for the power it will supply.
Oh yea, some of those Radio Shack power supplies were unregulated. :-)
TDD
Oscar_Lives
"Home Guy" <Ho...@Guy.com> wrote in message news:4D02ED42...@Guy.com...
> Steve full-quoted:
>
>> So your saying that the "reliable life span" of the new furnaces
>> is only 6 - 7 years??
>
> What-ever they are, they're not going to last as long as the ones being
> made 30 and 40 years ago - many of which are still functional even if
> they've been replaced by new garbage.
>
>> however when correctly installed, properly adjusted, and with
>> correctly sized ductwork
>
> Don't give me that "correctly installed" crap.
>
> A furnace is a box where you connect wires and ducting and turn the
> friggin thing on. It's a glorified barbeque.
>
> Any new furnace that can't be plugged into any existing house's ductwork
> and work correctly is a piece of shit.
>
> As bad as the existing ductwork is or can be, you shouldn't have to tear
> it down and re-do it just to satisfy the hyper-sensitive requirements of
> a new furnace or it's delicate, wimpy ECM blower motor.
>
This has got to be a spammer. No one is that stupid.
What a fricken dumbass!
cl...@snyder.on.ca
>The Daring Dufas wrote:
>
>> From looking at the information, I understand that the 1/2hp ECM
>> motor is the replacement for 1/3 through 1/2hp PSC motors and the
>> 1hp ECM is the replacement for the 3/4 through 1hp motors.
>
>Would you even use a 1/2 hp ECM motor for a home furnace? You certainly
>wouldn't save any money if you were replacing a 1/4 hp single-speed PSC
>motor with these 1/2 hp ECM units.
It's been a long time since I've seen a 1/4hp residential blower motor
1/3 seems to be pretty well standard for heating, with 1/2 HP being
very common with A/C
>
>> The ECM motors are adaptable according to the literature and
>> have the programming to learn how to operate
>
>How exactly do they do that?
>
>How does a motor know how much CFM the fan is moving?
It knows how fast it is turning and how much current it is drawing.
The current draw is a direct function of the load on the motor, which
decreases as the flow decreases
>
>Are there pressure or flow sensors mounted in the duct work for that?
>
>How would you use one of those replacement motors when you have an
>ordinary single-speed PSC motor in a 25+ year old furnace?
If you have a belt drive blower you will need to replace it with a
direct drive blower, or cobble together some kind of mount and pulley
setup.
>
>Can you apply 115 vac directly to those motors to the appropriate set of
>wires to make them operate - to hell with this learning crap?
That's all you do - the
learning" is built in.
>
>I don't get this learning crap anyways. What is an ECM motor supposed
>to learn? Don't you just want it to turn at a given RPM? Why all the
>fuss about finessing the CFM?
For more economy of operation. Turning the fan too fast can just draw
more power, without moving any more air.
>
>If the controller can make the unit start at low RPM and then speed up,
>that's great. Do it. Why worry about CFM? If the house isin't
>reaching the thermostat set-point fast enough, then speed up the motor,
>or turn up the burners.
That's fine if you are not trying to enhance efficiency.
>
>To me, the feedback the motor controller should get is the difference
>between actual house temperature and the thermostat set-point
>temperature. The smaller that difference, the slower the motor needs to
>turn and the less BTU's the furnace needs to put out.
Moving less air does not provide fewer BTUs - it just makes the air
hotter. Adjusting the amount of flame is what the motherboard you have
been cuesing for the last week or two can do. Mine is a 2 stage
burner, but there are "modulating" burners as well, that CAN control
the amount of heat produced, according to the number of BTUs required
(delta between current and desired temperatures)
> What the actual
>CFM is is neither here nor there. If the occupants want to over-ride
>the motor RPM to get ambient circulation, then fine, given them the
>option for low and medium speed constant circulation mode based on motor
>RPM - not on some sort of "learning" crap.
You just don't (and won't - ever, by the looks of things) get it.
cl...@snyder.on.ca
And the switch mode regulator can take the place of both. It is
GENERALLY used in a series configuration because it is more efficient
that way.
k...@att.bizzzzzzzzzzzz
Switching shunt regulators are exceedingly rare because the gain generally
isn't worth the cost. Another topology almost always wins.
The Daring Dufas
I came across a ferroresonant transformer power supply in a piece of
gear a friend had and he was mystified by the darn thing and why it
wasn't working. I obtained a replacement oil filled capacitor from an
electric motor rewind shop and got the equipment working again. He had
worked with all manner of DC voltage regulators but had never seen an
AC voltage regulator. I guess it helps to broaden your horizons in a
search for knowledge. :-)
TDD
k...@att.bizzzzzzzzzzzz
<the-dari...@stinky.net> wrote:
They also are not often used anymore because it's cheaper to use a switcher of
some sort. Iron is expensive. Silicon is cheap.
The Daring Dufas
I have a notion that the constant voltage transformer is a lot less
susceptible to voltage spikes and lightening strikes than a switcher.
I've installed a lot of them to protect phone systems power supplies.
The things work well as AC line filters and isolators.
TDD
Daniel who wants to know
>
> The power consumption of the 1/2 hp unit (6.3 A at 115 V) seems
> excessive.
>
That is amperage draw not power consumption.
The GE ECM units don't have any PFC so they have the same roughly .6 power
factor as any old computer power supply that just has a diode bridge and
capacitor at the input. That 6.3x120x.6 is roughly 454 watts. Since 1hp is
746 watts that puts the efficiency at about 82%
Daniel who wants to know
news:36fag6peafqeme4pl...@4ax.com...
>
> Moving less air does not provide fewer BTUs - it just makes the air
> hotter. Adjusting the amount of flame is what the motherboard you have
> been cuesing for the last week or two can do. Mine is a 2 stage
> burner, but there are "modulating" burners as well, that CAN control
> the amount of heat produced, according to the number of BTUs required
> (delta between current and desired temperatures)
>
The fun part is on an induced draft furnace with an in-shot burner set you
can't reduce the gas flow without also slowing down the inducer motor so
modulating furnaces and I assume your 2 stage have a small ECM for the
inducer too that varies speed/flow to match the fuel flow.
cl...@snyder.on.ca
<k...@att.bizzzzzzzzzzzz> wrote:
One place switching shunt regulators ARE used is on permanent magnet
brushless "alternators" on small engines and some motorcycles.
With per-mag "alternators" or "dynamos" the output cannot be
controlled, so shunt regulators are used. Linear shunt regulators have
proven rather short-lived in some apps, so the higher-end units have
gone to switch-mode regs.
cl...@snyder.on.ca
<k...@att.bizzzzzzzzzzzz> wrote:
>>
>>I came across a ferroresonant transformer power supply in a piece of
>>gear a friend had and he was mystified by the darn thing and why it
>>wasn't working. I obtained a replacement oil filled capacitor from an
>>electric motor rewind shop and got the equipment working again. He had
>>worked with all manner of DC voltage regulators but had never seen an
>>AC voltage regulator. I guess it helps to broaden your horizons in a
>>search for knowledge. :-)
>
>They also are not often used anymore because it's cheaper to use a switcher of
>some sort. Iron is expensive. Silicon is cheap.
Pound for pound iron is a LOT cheaper than the copper that is also
required - and MUCH cheaper than silicon.
It's just you need so much LESS silicon to do the job - and less iron
and copper when the frequency is in the khz or mhz range.
k...@att.bizzzzzzzzzzzz
>On Sun, 12 Dec 2010 19:52:10 -0600, "k...@att.bizzzzzzzzzzzz"
><k...@att.bizzzzzzzzzzzz> wrote:
>
>>>
>>>I came across a ferroresonant transformer power supply in a piece of
>>>gear a friend had and he was mystified by the darn thing and why it
>>>wasn't working. I obtained a replacement oil filled capacitor from an
>>>electric motor rewind shop and got the equipment working again. He had
>>>worked with all manner of DC voltage regulators but had never seen an
>>>AC voltage regulator. I guess it helps to broaden your horizons in a
>>>search for knowledge. :-)
>>
>>They also are not often used anymore because it's cheaper to use a switcher of
>>some sort. Iron is expensive. Silicon is cheap.
> Pound for pound iron is a LOT cheaper than the copper that is also
>required - and MUCH cheaper than silicon.
Which, of course, is a *silly* argument.
>It's just you need so much LESS silicon to do the job - and less iron
>and copper when the frequency is in the khz or mhz range.
Ran across one lately that runs at 180MHz so the (isolation) transformer could
be integrated on the chip.
Home Guy
> It's been a long time since I've seen a 1/4hp residential blower
> motor 1/3 seems to be pretty well standard for heating, with 1/2
> HP being very common with A/C
You might be right.
The motor in my furnace is this:
Emerson SA55NXTE-4513
1/3 HP, 1725 RPM, 5.4 A
It's got a 5" pulley wheel on it, driving a fan with a 7" pulley wheel.
> >How does a motor know how much CFM the fan is moving?
>
> It knows how fast it is turning and how much current it is
> drawing.
But the motor can't possibly know how many CFM of air is being moved
with each turn of the fan rotor.
> The current draw is a direct function of the load on the motor,
> which decreases as the flow decreases
Actually, once you get the air in the house moving, you should also see
a reduction in load. Also, I'm guessing that load will not increase
linearly with air-speed or CFM.
> > I don't get this learning crap anyways. What is an ECM motor
> > supposed to learn? Don't you just want it to turn at a given
> > RPM? Why all the fuss about finessing the CFM?
>
> For more economy of operation. Turning the fan too fast can just
> draw more power, without moving any more air.
If my existing motor is turning at 1725 RPM, and if I'm satisfied by the
breeze generated by that RPM, then I sure as hell wouldn't want an ECM
motor making it's own decisions about what RPM *it* wants to operate at.
The point of an ECM motor is that its supposed to be more efficient than
a PSC motor at ALL rpm's. So if I drop in an ECM motor and wire it up
for single-speed operation, I sure as hell would want that speed to be a
constant 1725 RPM.
> > If the controller can make the unit start at low RPM and then
> > speed up, that's great. Do it. Why worry about CFM? If the
> > house isin't reaching the thermostat set-point fast enough,
> > then speed up the motor, or turn up the burners.
>
> That's fine if you are not trying to enhance efficiency.
All you ECM-motor apologists are saying that ECM motors are *always*
more efficient than PSC motors regardless what RPM they operate at. So
now you're backtracking by saying that there's no savings when you
replace a PSC motor with ECM if you force the ECM motor to operate at
same, constant RPM that the PSC motor did.
What you're saying is that I'm supposed to allow the ECM motor to
"learn" and to reduce it's RPM.
That's no different than if I were to replace my 1/3 hp motor with 1/4
hp and put a smaller pulley on the motor vs what I have now. I will use
less electricity and the fan speed will be reduced.
cl...@snyder.on.ca
>cl...@snyder.on.ca unnecessarily full-quoted:
>
>> It's been a long time since I've seen a 1/4hp residential blower
>> motor 1/3 seems to be pretty well standard for heating, with 1/2
>> HP being very common with A/C
>
>You might be right.
>
>The motor in my furnace is this:
>
>Emerson SA55NXTE-4513
>1/3 HP, 1725 RPM, 5.4 A
>
>It's got a 5" pulley wheel on it, driving a fan with a 7" pulley wheel.
>
>> >How does a motor know how much CFM the fan is moving?
>>
>> It knows how fast it is turning and how much current it is
>> drawing.
>
>But the motor can't possibly know how many CFM of air is being moved
>with each turn of the fan rotor.
It doesn't have to - it's a relative thing - the motor adjusts itself
by RPM and current to the most efficient point - at least that's what
I gathered. If it runs too fast so the fan is "throttled" the current
drops for the speed it is running at, so the motor can slow down 'till
the current/rpm ratio ballances out.
>
>> The current draw is a direct function of the load on the motor,
>> which decreases as the flow decreases
>
>Actually, once you get the air in the house moving, you should also see
>a reduction in load. Also, I'm guessing that load will not increase
>linearly with air-speed or CFM.
You are right - partly. The inertia of the air is not much af a
factor, what with air being compressible and all, so there is not much
change in power required from "startup" to "air moving" - but the load
is not necessarily linear with air-speed or air flow. The
counterintuitive thing is the load DROPS when the back-pressure
increases. (partly because the actual air movement drops and partly
because of the way air behaves in a centrifugal blower (any fluid,
actually - look at cavitation in a water pump)
>
>> > I don't get this learning crap anyways. What is an ECM motor
>> > supposed to learn? Don't you just want it to turn at a given
>> > RPM? Why all the fuss about finessing the CFM?
>>
>> For more economy of operation. Turning the fan too fast can just
>> draw more power, without moving any more air.
>
>If my existing motor is turning at 1725 RPM, and if I'm satisfied by the
>breeze generated by that RPM, then I sure as hell wouldn't want an ECM
>motor making it's own decisions about what RPM *it* wants to operate at.
>
>The point of an ECM motor is that its supposed to be more efficient than
>a PSC motor at ALL rpm's. So if I drop in an ECM motor and wire it up
>for single-speed operation, I sure as hell would want that speed to be a
>constant 1725 RPM.
And it would be if that is the right speed - but it MIGHT move just as
much air at 1500, or 1375. It might actually move marginally MORE air
at a lower speed, because the blower itself may be more efficient at a
lower speed.
>
>> > If the controller can make the unit start at low RPM and then
>> > speed up, that's great. Do it. Why worry about CFM? If the
>> > house isin't reaching the thermostat set-point fast enough,
>> > then speed up the motor, or turn up the burners.
>>
>> That's fine if you are not trying to enhance efficiency.
>
>All you ECM-motor apologists are saying that ECM motors are *always*
>more efficient than PSC motors regardless what RPM they operate at. So
>now you're backtracking by saying that there's no savings when you
>replace a PSC motor with ECM if you force the ECM motor to operate at
>same, constant RPM that the PSC motor did.
No, not saying that. It will be somewhat more efficent at the same
speed, but may be considerably more efficient, while movong the same
amount of air, at a lower speed.
>
>What you're saying is that I'm supposed to allow the ECM motor to
>"learn" and to reduce it's RPM.
>
>That's no different than if I were to replace my 1/3 hp motor with 1/4
>hp and put a smaller pulley on the motor vs what I have now. I will use
>less electricity and the fan speed will be reduced.
And , depending on your furnace and setup, it may actually be more
effective that way.(as well as more efficient)
Home Guy
> > But the motor can't possibly know how many CFM of air is being
> > moved with each turn of the fan rotor.
> It doesn't have to - it's a relative thing - the motor adjusts
> itself by RPM and current to the most efficient point -
> at least that's what I gathered.
Sure, the motor can know a lot about it's own current useage as a
function of it's own RPM.
But it can't know anything about RPM and fan CFM - without getting
feedback from air-flow / air-pressure sensors mounted in the ductwork.
ECM motors can't reduce their RPM to, say, 1600 RPM and magically give
me the same CFM as my motor running at 1750 RPM - both given the same
fan to turn in the same duct system.
> > The point of an ECM motor is that its supposed to be more
> > efficient than a PSC motor at ALL rpm's. So if I drop in
> > an ECM motor and wire it up for single-speed operation, I
> > sure as hell would want that speed to be a constant 1725 RPM.
>
> And it would be if that is the right speed
Who says what the right speed is?
> - but it MIGHT move just as much air at 1500, or 1375.
> It might actually move marginally MORE air at a lower
> speed, because the blower itself may be more efficient
> at a lower speed.
Ok, you need to step back and re-think this.
Within a normal range of operation, there is no way that I can turn a
given fan at a slower speed and yet get more CFM being moved by that
fan.
Again, you think that ECM motors can magically make a given fan move
more (or even the same) CFM at a slower rotational speed than a PSC
motor at the same speed. You're going to have to explain the physics
behind such a phenomena.
cl...@snyder.on.ca
>cl...@snyder.on.ca wrote:
>
>> > But the motor can't possibly know how many CFM of air is being
>> > moved with each turn of the fan rotor.
>
>> It doesn't have to - it's a relative thing - the motor adjusts
>> itself by RPM and current to the most efficient point -
>> at least that's what I gathered.
>
>Sure, the motor can know a lot about it's own current useage as a
>function of it's own RPM.
>
>But it can't know anything about RPM and fan CFM - without getting
>feedback from air-flow / air-pressure sensors mounted in the ductwork.
>
>ECM motors can't reduce their RPM to, say, 1600 RPM and magically give
>me the same CFM as my motor running at 1750 RPM - both given the same
>fan to turn in the same duct system.
>
>> > The point of an ECM motor is that its supposed to be more
>> > efficient than a PSC motor at ALL rpm's. So if I drop in
>> > an ECM motor and wire it up for single-speed operation, I
>> > sure as hell would want that speed to be a constant 1725 RPM.
>>
>> And it would be if that is the right speed
>
>Who says what the right speed is?
The right speed is the speed that 1) - moves the most air with the
least power or 2) allows the most heat to be extracted from the heat
exchanger by optimizing the air flow.
Moving more air does not necessarily translate to providing more heat.
>
>> - but it MIGHT move just as much air at 1500, or 1375.
>> It might actually move marginally MORE air at a lower
>> speed, because the blower itself may be more efficient
>> at a lower speed.
>
>Ok, you need to step back and re-think this.
>
>Within a normal range of operation, there is no way that I can turn a
>given fan at a slower speed and yet get more CFM being moved by that
>fan.
Counterintuitive, yes - but if YOUR fan is turning too fast, turning
it slower CAN provide the same or even higher air flow - and use less
power to do it.
>
>Again, you think that ECM motors can magically make a given fan move
>more (or even the same) CFM at a slower rotational speed than a PSC
>motor at the same speed. You're going to have to explain the physics
>behind such a phenomena.
I didn't say that. If you could slow down the PSC motor you could
have the same effect.. You could use a brushed DC motor and variable
voltage to get the same effect - but ECM motors are less maintenance
intensive, longer lived, and (can be)more efficient.
Home Guy
> >Who says what the right speed is?
>
> The right speed is the speed that 1) - moves the most air with the
> least power or 2) allows the most heat to be extracted from the
> heat exchanger by optimizing the air flow.
A drop-in replacement ECM motor that's replacing a single-speed PSC
motor can't know how much air it's moving, because it doesn't know the
size of the fan it's turning nor does it have duct-mounted sensors to
tell it the CFM of air being pushed through the ducts.
A drop-in replacement ECM motor can't know anything about how much heat
is being extracted by the heat exchanger, because it doesn't have
temperature sensors telling it the input and output furnace air
temperature.
A drop-in replacement ECM motor can "learn" it's energy-useage vs RPM
curve is once it's been installed into a given home's furnace, but that
doesn't mean that the most efficient RPM will be satisfactory for the
comfort or desire of the home owner.
> Moving more air does not necessarily translate to providing
> more heat.
A drop-in replacement ECM motor will not be getting any feedback from
any temperature sensors, so that point is moot.
> > Within a normal range of operation, there is no way that I
> > can turn a given fan at a slower speed and yet get more
> > CFM being moved by that fan.
>
> Counterintuitive, yes - but if YOUR fan is turning too fast
You actually believe that a 1/3 HP motor running at 1750 rpm though a
reduction pulley is going to be turning the furnace fan too fast - to
the point that it's actually pushing *less* CFM through a "normal"
home's duct system as compared to if it was turning slower?
I said given a normal range of operation - not given some ridiculously
high RPM.
> > Again, you think that ECM motors can magically make a given
> > fan move more (or even the same) CFM at a slower rotational
> > speed than a PSC motor at the same speed. You're going to
> > have to explain the physics behind such a phenomena.
> I didn't say that. If you could slow down the PSC motor you
> could have the same effect.
What effect?
If I slow down any motor, the fan will turn more slowly, and I will get
less CFM.
You keep wanting to insist that in every case where there is a PSC
motor, that it's almost certainly turning it's fan faster than it needs
to, or faster than the home-owner wants.
Just because an ECM motor *can* run slower than a PSC motor doesn't mean
that the resulting CFM is what the home-owner wants.
> but ECM motors are less maintenance intensive, longer lived,
> and (can be)more efficient.
Tell me why an ECM motor is longer lived - given that we've really only
had them in consumer furnaces for the past 10, 15 years max.
PSC motors don't have brushes, nor do they have sensitive electronics
that are vulnerable to power surges and nearby lightning strikes, nor do
they care much about pushing air though high-resistance ductwork.
What is it about the construction of a PSC motor can you point to as
being more sensitive or less durable or more prone to failure vs an ECM
motor?
cl...@snyder.on.ca
>> > Again, you think that ECM motors can magically make a given
>> > fan move more (or even the same) CFM at a slower rotational
>> > speed than a PSC motor at the same speed. You're going to
>> > have to explain the physics behind such a phenomena.
>
>> I didn't say that. If you could slow down the PSC motor you
>> could have the same effect.
>
>What effect?
>
>If I slow down any motor, the fan will turn more slowly, and I will get
>less CFM.
That is not NECESSARILY true.
>
>You keep wanting to insist that in every case where there is a PSC
>motor, that it's almost certainly turning it's fan faster than it needs
>to, or faster than the home-owner wants.
I didn't say in EVERY case
>
>Just because an ECM motor *can* run slower than a PSC motor doesn't mean
>that the resulting CFM is what the home-owner wants.
And the homeowner is often too stupid to realise that what the FURNACE
wants is more important than what he thinks he wants, in some
instances.
>
>> but ECM motors are less maintenance intensive, longer lived,
>> and (can be)more efficient.
>
>Tell me why an ECM motor is longer lived - given that we've really only
>had them in consumer furnaces for the past 10, 15 years max.
Lets see. How long have electronically commutated motors been in
common use elsewhere????
DC "muffin" fans have been in use in computer power supplies since
before the IBM PC came on the market some 30 years ago. If the
bearings don't seize up they run virtually forever.
And the ECM, or "Smart Motor" was first marketted for furnace use by
general electric in 1969.
That's FORTY TWO YEARS of history.
>
>PSC motors don't have brushes, nor do they have sensitive electronics
>that are vulnerable to power surges and nearby lightning strikes, nor do
>they care much about pushing air though high-resistance ductwork.
>
And nor are they anything approaching anyone's definition of
efficient.
>What is it about the construction of a PSC motor can you point to as
>being more sensitive or less durable or more prone to failure vs an ECM
>motor?
Because of lower efficiency they tend to run hotter.
Installed PSC motor efficiency is generally in the 12-45% range, which
means a LOT of heat is produced. ECM motors generally run 65 to 72%
efficiency as installed.. That means a LOT LESS HEAT.
Add to this the FACT that a majority of the heat in a PSC motor is
produced in the rotor, whech means a lot of heat is transferred out of
the motor through the shaft and bearings. This reduces bearing life
and stresses bearing lubrication.
I'm not saying PSC motors are failing at extremely high rates - but I
have had them fail in signiificantly less than 20 years, and I reject
yout hypotheses that ECM motors are either "puny", short lived, or
intrinsically trouble prone.
I just saw a few weeks ago a ECM less tham 4 inches in diameter and
less than 4 inches long that will put out 14 HP.
In the 20-200 HP range, Brushless DC motors (ecms) are actually less
costly than brush DC motors or any other variable/controlable speed AC
motors and are extensively used in industrial applications
Steve
"Home Guy" <Ho...@Guy.com> wrote in message news:4D06E5BE...@Guy.com...
Furnaces with ECM motors generally have a larger blower wheel and housing so
they can turn slower and move the required volume of air. Air volume and
velocity is set up for specific amount of heat temperature rise in furnaces
and 400cfm per ton for heat pumps and air conditioning. Also because the ECM
motors are turning slower, there is a whole lot less blower noise, but the
ductwork has to be correctly sized. If everything is right with the world,
the system is correctly designed, sized, and installed, it should have
minimal energy usage, be nearly silent, no drafts, and no more than 1F temp
difference between any 2 rooms.
If you want to continue screwing with your furnace, have at it...... just as
soon as you get done using the hand crank to start your car.
The Daring Dufas
ECM motors are being marketed to replace common evaporator fan motors in
commercial refrigeration. Those refrigerated cases you see in the
grocery store are getting ECM fan motors.
TDD
The Daring Dufas
Hey, I could hand crank my 1967 Renault 10 with the screw jack handle. :-)
TDD
Home Guy
> > If I slow down any motor, the fan will turn more slowly, and I
> > will get less CFM.
>
> That is not NECESSARILY true.
Unless you can show where someone has made some blower CFM measurements
in a real house, then you have no real evidense to support that
paradoxical statement.
And in any case, an ECM motor has no way to know how much CFM is being
moved by the fan its running, especially as a drop-in replacement for a
PSC motor.
And I bet that modern furnaces that come with ECM motors also don't know
how much CFM they're actually pushing. They probably only know
indirectly by monitoring return-air and output-air temperature
difference. Do any of them have an integrated wind-speed sensor?
> > You keep wanting to insist that in every case where there is
> > a PSC motor, that it's almost certainly turning it's fan
> > faster than it needs to, or faster than the home-owner
> > wants.
>
> I didn't say in EVERY case
Then put a number on it.
> > Just because an ECM motor *can* run slower than a PSC motor
> > doesn't mean that the resulting CFM is what the home-owner
> > wants.
>
> And the homeowner is often too stupid to realise that what the
> FURNACE wants is more important than what he thinks he wants,
> in some instances.
The home-owner is "often" too stupid ... in some instances. ?
That's a mixed message. You want to say that some arbitrarily large
fraction of home-owners would (or are) choosing a fan-speed that too
high (you'd have to show me how they have any real control over that,
btw) then you back away by saying "in some instances".
You are showing a strange bias against homeowners that is affecting your
ability to think rationally about this.
> > Tell me why an ECM motor is longer lived - given that we've
> > really only had them in consumer furnaces for the past 10,
> > 15 years max.
>
> Lets see. How long have electronically commutated motors been
> in common use elsewhere????
Yes, let's compare these other situations, where micro-power DC motors
have been used:
> DC "muffin" fans have been in use in computer power supplies
> since before the IBM PC came on the market some 30 years ago.
> If the bearings don't seize up they run virtually forever.
So you think that these tiny, micro-power DC motors make for a good
analogy when we're talking about the furnace fan motor market eh?
> And the ECM, or "Smart Motor" was first marketted for furnace
> use by general electric in 1969.
> That's FORTY TWO YEARS of history.
Tell me how many consumer furnaces were available in 1985 with ECM
motors.
And you haven't told me anything to support your claim that ECM motors
last longer.
Saying that the first ECM motor was made a hundred years ago, or that GE
supposedly actually sold a furnace with an ECM motor in 1969 (which
maybe they withdrew from the market a few years later ?) is not an
answer to why ECM motors last longer (your claim).
> > PSC motors don't have brushes, nor do they have sensitive
> > electronics that are vulnerable to power surges and nearby
> > lightning strikes, nor do they care much about pushing air
> > though high-resistance ductwork.
>
> And nor are they anything approaching anyone's definition of
> efficient.
Don't change the subject. We're talking about longevity, not
efficiency.
> > What is it about the construction of a PSC motor can you
> > point to as being more sensitive or less durable or more
> > prone to failure vs an ECM motor?
>
> Because of lower efficiency they tend to run hotter.
Yes, they run hotter. They are also constantly cooled by the airflow
generated by the fan.
Tell me which motor is more likely to survive constant use in a
high-resistance duct system? Or survive a fan bearing that gets
gummed-up over time? Or a filter that's not properly cared for? Or a
power spike or brown-out on the AC grid?
> Installed PSC motor efficiency is generally in the 12-45% range,
That depends on how many PSC motors are multi-speed vs single speed.
And you can get high-efficienty PSC motors in the range of 62%, as
claimed here:
http://www.nailor.com/pdf/ecm_1.pdf
And I suggest you also read this:
http://energyexperts.org/EnergySolutionsDatabase/ResourceDetail.aspx?id=2613
Any furnace that has a shaded-pole variable-speed fan motor does have
horrible efficiency, and perhaps some people here are confusing
shaded-pole motors with PSC motors in these discussions about motor
efficiency.
It's clear that when we're talking about 1/4 and 1/3 hp single-speed PSC
motors, efficiencies up to 60 - 65% are obviously the norm, and bring us
much closer to ECM motor efficiency than most people think possible.
> I reject yout hypotheses that ECM motors are either "puny", short
> lived, or intrinsically trouble prone.
It's clear that some furnace makers are using puny or wimpy ECM motors
in their furnaces. But none of the HVAC regulars reading this will
chime in and agree.
ECM motors have sophisticated electronics that PSC motors don't have.
When-ever you include additional components into any system or device,
you have more points of failure. You stubbornly refuse to believe that
the electronics in an ECM motor represents an addition point-of-failure
that PSC motors simply don't have.
Steve
"Home Guy" <Ho...@Guy.com> wrote in message news:4D07828E...@Guy.com...
Ok homer, so when are you going to start you new job with the manufacturers
and/or governing bodies to redesign and reclassify furnaces so that you can
turn a multi billion dollar industry back in time 20 years??
cl...@snyder.on.ca
>
>The home-owner is "often" too stupid ... in some instances. ?
>
At least ONE.
I'm done. You are too stupid to be teachable.
tra...@optonline.net
> On Tue, 14 Dec 2010 09:43:26 -0500, Home Guy <H...@Guy.com> wrote:
>
> >The home-owner is "often" too stupid ... in some instances. ?
>
> At least ONE.
> I'm done. You are too stupid to be teachable.
Excuse me, but I think the points Home Guy are raising are perfectly
valid and you
can't just dismiss them. You claimed that slowing down a fan motor may
not lead to
less airflow. I agree, thatis possible, IF the fan is turning so
fast that it's no longer
moving air, ie cavitation has occured. But that isn't the abnormal
case we're discussing now, is it?
We're talking about a normally operating home forced air funace or AC.
Also, HG raised a perfectly valid question of how a drop in
replacement ECM motor
could learn anything about air flow. It can't directly measure the
CFM being moved.
He asked a question I'd like to know the answer to, which is in new
furnaces with ECM,
do they have air flow sensors?
Also, to add to HG's case, I think all the hoopla about constantly
circulating air 24/7 is
a bunch of BS. Why? Let;s look at my house, which I'd say is
typical. Furnace is in
the basement, returns are uninsulated and some to upstairs even flow
through outside walls.
Those ducts have no insulation, because the wall cavity is used for
the ducts and the insulation
that the normal cavities would have is absent. Also, typical ducting
is far from perfect,
with leaks in botht the returns and supply commong.
So, now I'm to believe that running a blower 24/7
when it's 20F outside, drawing the air through the cold basement, the
cold furnace that is not
fired up, through ducts that are in outside wall, etc, is a smart
thing? I don't care how much
you think you save in an ECM motor. Even if the energy to run the
blower is free, the rest of
the above equation spells loss to me.
cl...@snyder.on.ca
>On Dec 14, 12:44 pm, cl...@snyder.on.ca wrote:
>> On Tue, 14 Dec 2010 09:43:26 -0500, Home Guy <H...@Guy.com> wrote:
>>
>> >The home-owner is "often" too stupid ... in some instances. ?
>>
>> At least ONE.
>> I'm done. You are too stupid to be teachable.
>
>Excuse me, but I think the points Home Guy are raising are perfectly
>valid and you
>can't just dismiss them. You claimed that slowing down a fan motor may
>not lead to
> less airflow. I agree, thatis possible, IF the fan is turning so
>fast that it's no longer
> moving air, ie cavitation has occured. But that isn't the abnormal
>case we're discussing now, is it?
It is an all too common occurence when guys who do not understand what
is happening try to "fix" their furnace.
>We're talking about a normally operating home forced air funace or AC.
>
Which someone has screwed around with
>Also, HG raised a perfectly valid question of how a drop in
>replacement ECM motor
>could learn anything about air flow. It can't directly measure the
>CFM being moved.
>He asked a question I'd like to know the answer to, which is in new
>furnaces with ECM,
>do they have air flow sensors?
In most cases, if not all, no.
>
>Also, to add to HG's case, I think all the hoopla about constantly
>circulating air 24/7 is
>a bunch of BS. Why? Let;s look at my house, which I'd say is
>typical. Furnace is in
>the basement, returns are uninsulated and some to upstairs even flow
>through outside walls.
>Those ducts have no insulation, because the wall cavity is used for
>the ducts and the insulation
>that the normal cavities would have is absent. Also, typical ducting
>is far from perfect,
>with leaks in botht the returns and supply commong.
>
>So, now I'm to believe that running a blower 24/7
>when it's 20F outside, drawing the air through the cold basement,
Not all basements are cold. A very large percentage of urban
basements are heated, finished living space.
> the
>cold furnace that is not
>fired up, through ducts that are in outside wall, etc, is a smart
>thing? I don't care how much
>you think you save in an ECM motor. Even if the energy to run the
>blower is free, the rest of
>the above equation spells loss to me.
To you it might be.
To me, and many others, it is not.
And I've checked the air temp from the heat outlets on the outside
walls of my house - they are room temperature or better with the
burner not firing
I've stood up for HG on many issues - but he'll never get it. The days
of the model "T" are long gone - and the day of the standing pilot
light, atnospheric burner, PSC fan gas furnace are pretty well gone
too.
Taking all the "advancements" off of today's equipment will not make
it a) last longer b) work better c) cost less long term or d) run
better.
He first argues for resizing the jet - which I agreed with him about,
and adjusting the air dampers, which I also agreed with him on, then
he starts talking about putting the gas valve "between settings" -
referring to the 3 position gas valve as "variable", and adjusting the
flame by adjusting the gas shutoff valve on the 1" iron pipe feeding
the furnace. Sure he can reduce the flame that way - but it is sure
not the right, or even an adviseable way to do it.
Vic Smith
>
> Not all basements are cold. A very large percentage of urban
>basements are heated, finished living space.
We've beaten to death "modifying" furnaces to improve efficiency.
It can be done with older furnaces because they just weren't designed
with efficiency as a high priority. The priority was quick heat on
demand.
I wouldn't try modifying a modern "efficient" furnace.
Correct sizing is what you want, so more heat goes through the heat
exchanger and less up the stack.
Beyond that - and insulation - I've found the best way to reduce gas
use is to not heat where it isn't needed.
Working vents are important, as are just closing/opening doors.
All depends on where the thermostat is, and that can be moved if it
makes sense to your needs.
I like the idea of zoned heat, though I have no experience with it.
I just close or open vents and doors depending on what current needs
are.
--Vic
tra...@optonline.net
> On Tue, 14 Dec 2010 11:26:48 -0800 (PST), trad...@optonline.net wrote:
> >On Dec 14, 12:44 pm, cl...@snyder.on.ca wrote:
> >> On Tue, 14 Dec 2010 09:43:26 -0500, Home Guy <H...@Guy.com> wrote:
>
> >> >The home-owner is "often" too stupid ... in some instances. ?
>
> >> At least ONE.
> >> I'm done. You are too stupid to be teachable.
>
> >Excuse me, but I think the points Home Guy are raising are perfectly
> >valid and you
> >can't just dismiss them. You claimed that slowing down a fan motor may
> >not lead to
> > less airflow. I agree, thatis possible, IF the fan is turning so
> >fast that it's no longer
> > moving air, ie cavitation has occured. But that isn't the abnormal
> >case we're discussing now, is it?
>
> It is an all too common occurence when guys who do not understand what
> is happening try to "fix" their furnace.
But here's the problem. You claimed that slowing down a blower
doesn't necessarily
reduce the air flow. If you were taking about the pathological case
where the blower
can't move air because it's cavitating, they you should have pointed
that out. Because
if that's the case, there is a problem that needs to be fixed with the
system that has
nothing to do with an ECM vs conventional motor. To do otherwise is
just to spread FUD.
>We're talking about a normally operating home forced air funace or AC.
>
> Which someone has screwed around with>
Who said anyone was screwing around with anything? In the current
discussion, all I saw
was Home Guy asking some very relevant questions about ECM motors,
including those
installed in modern furnaces at the factory.
>Also, HG raised a perfectly valid question of how a drop in
> >replacement ECM motor
> >could learn anything about air flow. It can't directly measure the
> >CFM being moved.
> >He asked a question I'd like to know the answer to, which is in new
> >furnaces with ECM,
> >do they have air flow sensors?
>
> In most cases, if not all, no.
>
>
So then Home Guy's point remains valid. Apparently the motor can't
know
how much air is actually flowing. Sounds more and more like it's
just a multi-
speed motor that will be more efficient in most applications, ie those
with typical
or better ducting. In the typical install, that equates to using 20%
less energy.
Now, if we don't intend to run our blower 24/7, instead using it only
when actually
heating or cooling, how much will that amount to?
The question of course remains if cost is the only issue, with
typical use, will you save enough in electricity to recover the cost?
I'm looking
at quotes where it's $1000 more for a 95%efficiency furnace with a two
stage
burner and variable speed ECM blower, compared to one without those
features.
Clearly all that cost isn't due to the blower
but it comes with it, without choice. Combine that with the exposure
to increased
repair cost for the ECM and drive electronics and I'm not sure of the
value proposition.
If you have issues other than saving energy that the variable speed
drive will help with
then it's another story. But for me, I don't see that extra value.
>
> >Also, to add to HG's case, I think all the hoopla about constantly
> >circulating air 24/7 is
> >a bunch of BS. Why? Let;s look at my house, which I'd say is
> >typical. Furnace is in
> >the basement, returns are uninsulated and some to upstairs even flow
> >through outside walls.
> >Those ducts have no insulation, because the wall cavity is used for
> >the ducts and the insulation
> >that the normal cavities would have is absent. Also, typical ducting
> >is far from perfect,
> >with leaks in botht the returns and supply commong.
>
> >So, now I'm to believe that running a blower 24/7
> >when it's 20F outside, drawing the air through the cold basement,
>
> Not all basements are cold. A very large percentage of urban
> basements are heated, finished living space.
Around here, NJ/NYC area, I'd say the majority are not. My house
isn't. And
I see plenty of new construction where they have dual zone systems,
putting
one furnace in an unfinished basement, the other in the attic, which
is even
worse if you keep air moving 24/7.
Also, not one person that's hawking the wonders of variable speed
blowers even
mentions the above points. It's obvious I don't have a finished
basement and not
one contractor said a word about it. All of them are spouting mostly
what we call
marketing BS. Like the variable speed blower in a 5 ton AC is gonna
use the same
electricity as a 40W bulb. That the furnace which is still rated at
95% AFUE, just
like the single stage, is now going to be way more efficient. Both of
those are fiction.
There's some truth that the furnace will be slightly more efficient
when firing at 70%,
but from physics and what I've been able to gather, it's a small
percentage, a couple
percent at best. And around here, it's gonna be firing at 70% in the
Fall and Spring,
when I use the smallest amount of energy anyway. So the gas usage
difference is very slight.
>
> > the
> >cold furnace that is not
> >fired up, through ducts that are in outside wall, etc, is a smart
> >thing? I don't care how much
> >you think you save in an ECM motor. Even if the energy to run the
> >blower is free, the rest of
> >the above equation spells loss to me.
>
> To you it might be.
> To me, and many others, it is not.
You dismissed all the above on the basis that there are lots of
finished basements,
so the heat lost by constantly pumping hot air through cold basements,
garages,
attics etc isn't an issue. I say it is.
>
> And I've checked the air temp from the heat outlets on the outside
> walls of my house - they are room temperature or better with the
> burner not firing
Explain to us how it's possible to send air through typical ducts in
the outside walls
of homes when it's 20 outside and not have them lose heat. Maybe
you've re-written
the laws of physics. Actually it sounds like you have, since you say
the air coming
out is room temp or better with the burner off. How is it possible
to gain heat?
>
> I've stood up for HG on many issues - but he'll never get it. The days
> of the model "T" are long gone - and the day of the standing pilot
> light, atnospheric burner, PSC fan gas furnace are pretty well gone
> too.
> Taking all the "advancements" off of today's equipment will not make
> it a) last longer b) work better c) cost less long term or d) run
> better.
>
> He first argues for resizing the jet - which I agreed with him about,
> and adjusting the air dampers, which I also agreed with him on, then
> he starts talking about putting the gas valve "between settings" -
> referring to the 3 position gas valve as "variable", and adjusting the
> flame by adjusting the gas shutoff valve on the 1" iron pipe feeding
> the furnace. Sure he can reduce the flame that way - but it is sure
> not the right, or even an adviseable way to do it.- Hide quoted text -
>
I can take the two stage complexity and the ECM out by simply choosing
to not buy it and still get a 95% AFUE furnace. And as to repair
cost, he
has a valid issue. Are you going to claim that the replacement cost
of the
ECM motor or drive electronics is the same as a conventional motor?
I've
seen plenty of stories here over the years of people paying $800 to
replace them.
If a plain old motor goes, I can replace it for $100. Does that mean
all the technology in today's furnaces isn't justified? No, but IMO
you can't lump
it all together. It's like buying a new car that has headlights that
autmatically
adjust and react to the cars pitch up or down at any given moment, to
maintain
them perfectly pointed evenly ahead. A nifty
feature? Yes. But when that system goes out, it sure isn't gonna
cost the
same to fix as a conventional headlamp system.
Oscar_Lives
<cl...@snyder.on.ca> wrote in message news:36bfg656h6jckhuor...@4ax.com...
THANKS. Now go away and STOP CROSS-POSTING.
Home Guy
> But here's the problem. You claimed that slowing down a blower
> doesn't necessarily reduce the air flow.
Mr. Snyder appears to have painted himself into a corner over the finer
details of the operation of ECM motors and seems to just want to walk
away from this conversation instead of admitting he's wrong or
mis-informed.
> I'm looking at quotes where it's $1000 more for a 95%efficiency
> furnace with a two stage burner and variable speed ECM blower,
> compared to one without those features.
There are several nation-wide HVAC retailers with websites listing
prices for furnaces. I was looking at one a few days ago, and they
listed various Goodman furnaces with various efficiences (from
non-condensing to condensing, etc) and the price for the furnaces ranged
from $750 to $1500 if I remember correctly.
Have a look at these retailers / wholesalers:
http://www.alpinehomeair.com/kitbuilder_new/
http://www.thefurnaceoutlet.com
http://www.gsistore.com/
http://www.acwholesalers.com/Goodman_Gas_Furnaces_s/160.htm
https://www.freemanliquidators.com/productcart/pc/HVAC-c2.htm
http://www.ductworks.net/xcart/home.php?js=y
http://www.theacoutlet.com/index.php
See if the furnaces you've been quoted on are carried on any of the
above sites to get an idea of just how much your local contractor is
over-charging you for the hardware.
I have a hunch that just like roofer's who over-charge you for the
shingles, you'll pay a 50% premium for the hardware when you buy an
entire package (furnace + installation) from a local contractor.
Your $1000 difference in the cost of a furnace with and without 95% /
2-stage / ECM is insane. Most 90+ furnaces seem to cost around $1000
judging by what I see on those sites.
See what your contractors say about just installing the furnace that you
buy on-line. See if they balk and weazel their way out of doing that.
> So, now I'm to believe that running a blower 24/7 when it's
> 20F outside, drawing the air through the cold basement,
Your point about running the fan 24/7 is lost on a lot of people.
Your house loses heat through the walls, windows, and ceiling. Doesn't
matter how much you insulate - the walls, windows, doors and ceiling are
the containment envelope for the heat in your house. You're not going
to loose heat through the wires or the plumbing.
And it's not just the basement walls (that's a red herring).
By running your fan 24/7, you're constantly forcing interior air to pass
against the walls, ceiling, windows and doors, where the air will do
it's best to either pick up heat (in the summer) or dump heat (in the
winter) against those surfaces and tranfer heat to (or from) the
outside. It's in the winter that this heat transfer is particularly of
interested to us.
What you want is to achieve a still-air condition where there is no air
motion inside your house. This condition will result in the least
amount of heat being drawn off the interior objects (furnature, interior
walls, floors, etc) and deposited against your exterior walls, windows,
doors, etc. But with a forced-air system, you have no choice but to
move air around and cause a breeze.
So while running a furnace 24/7 with the furnace dumping exactly as much
heat into the house as the house is losing to the outside is (in theory)
the most efficient way to operate, the very act of moving the air around
inside your house is contributing to heat loss to the outside world. So
it's probably the case that a furnace duty cycle less than 100% is more
efficient at heating your house while conserving interior heat at the
same time. I'm thinking more like 70% is probably where you want to be,
and certainly to NOT run your fan at any time when your furnace is not
on.
Steve
"Home Guy" <Ho...@Guy.com> wrote in message news:4D082E53...@Guy.com...
Legitmate contractors will not install *ANY* equipment that the customer has
purchased off the internet for 2 reasons.....
1) Manufacturers warranty is null and void for any and all equipment
purchased off the internet.
2) Legitmate contractors cannot and will not assume *ANY* liability for said
equipment.
I charge what I do, because thats what it takes to keep my companys doors
open, and still make a small profit after all of the costs, expenses,
salaries, and taxes are paid. Here's a hint.....
"The bitter taste of a poor quality installation will linger far longer than
the initial sweetness of a low price."
The Daring Dufas
The finest equipment in the world is worthless if installed improperly.
I'm sure you've come across heartbreaking installations of expensive
systems that some hack put in and you have to break the bad news to a
very nice customer.
TDD
Steve
"The Daring Dufas" <the-dari...@stinky.net> wrote in message
news:ie9edf$bf7$1...@news.eternal-september.org...
The especially bad (dangerous) ones, I take pics of and forward to the city
code enforcement and/or county planners office, and the state fire marshal.
The Daring Dufas
I was at a deposition last week where the defendants attorney was
quizzing me about my training and where I got it. Nobody can supply
the training I've had. I started out repairing window units in the
early 1970's and self taught from there. My friends with all the
wallpaper come to me and ask me about this and that because I've
usually seen it. "Experience is a fools best teacher." Emerson. :-)
TDD
Home Guy
> > See what your contractors say about just installing the furnace
> > that you buy on-line. See if they balk and weazel their way out
> > of doing that.
>
> Legitmate contractors will not install *ANY* equipment that the
> customer has purchased off the internet for 2 reasons.....
>
> 1) Manufacturers warranty is null and void for any and all
> equipment purchased off the internet.
Where exactly is that written? Nice to see how you try to spread FUD
over this.
The manufacturer has no way to know exactly how a given furnace was
purchased, and it doesn't matter in any way, shape or form how a
new-in-box furnace makes it's way through the wholesale-retail chain to
the customer's basement.
Once there, installation by a "professional" contractor should satisfy
all the critera for the factory warranty.
> 2) Legitmate contractors cannot and will not assume *ANY* liability
> for said equipment.
The customer would not ask the contractor to assume any liability for
the equipment, only for the proper installation of said equipment, which
should be totally acceptible to you since you are installing perfectly
good equipment, perhaps exactly the same equipment that you sell to
other customers.
> I charge what I do, because thats what it takes to keep my companys
> doors open, and still make a small profit after all of the costs,
> expenses, salaries, and taxes are paid.
Your cost structure is your problem.
It must be emarassing to you when a customer finds out how much you
over-charge him for the same furnace that he can buy himself from these
various vendors.
> Here's a hint.....
> "The bitter taste of a poor quality installation
I'm separating purchase of the equipment from it's installation.
There is no rational argument that you can make against a home-owner
sourcing and purchasing the furnace for himself, and then contracting
you or some other HVAC company to install it.
Because at the end of the day, that's all you guys really do -
installation. You don't make the furnace, it just passes through your
hands on the way from the factory to the customer. So don't give us any
bull-crap that the customer *has to* buy it from you. That's a very
unprofessional way to operate.
Home Guy
> The finest equipment in the world is worthless if installed
> improperly.
You totally missed the point.
What's wrong with the customer buying a new furnace through one of those
national retailers / wholesalers, and then contracting a local HVAC
company to install it?
How would that result in improper installation?
The customer would save the 50%+ markup charged by the local HVAC
company for the furnace.