Attic Fans w/ attic furnace & water heater
Paul J. Lindsey
I'm researching attic fans to reduce my cooling bills. An installation
manual that I read at Home Depot said that if you had a gas furnace in your
attic, you needed an interlock switch so that the fan would shut-off when
the furnace came on. I'm guessing that it's so the combustion gases go up
the flue, not into the attic (carbon monoxide danger). Is this correct? I
also have a gas water heater in my attic, so I suspect I need an interlock
for it also.
Anyone know exactly what these are (some sort of relay)? and where to get
them?
Nels
Sorry for getting off the subject here, but...you have a water heater in your
*attic*!? I hope you have good homeowner's insurance.
Concerned and a bit worried for you,
Nelson
Plindsey
On Aug 09, 1996 18:44:03 in article <Re: Attic Fans w/ attic furnace &
the water heater is installed with both a drainage line from the relief
valve and a 4 inch deep drain pan with a drainage connection. Both
drainage line tee together and are routed outside the house. I thought it
was a strange place to put the water heater too, until I verified the
piping. Actually, you're more likely to get a leak from the water lines
going to a washing machine. I had a rubber hose rupture about six months
ago. Luckily, the washing machine was in the garage and I was home (but a
different home than now). I replaced the washing machine hoses with
braided steel. A pair of braided stel hoses were only about $12 more than
plain rubber ones. I think that braided steel lines should be standard on
those two story houses that have an upstairs laundry room.
About the water heater, I still not sure how I'm going to install a gas
water heater interlock for the attic fans. A gas water heater uses no
external power supply. Maybe a thermostatic switch at the top ot the
heater (under the draft hood) could be used to interrup power to the attic
fans. I'd like to keep it low voltage and use a relay to control the 115v
power though. I'm going to talk to a heating contractor next week.
r/ Paul
Michel Gagnon
Dans l'article (In article) <320BDB...@netins.net>, nel...@netins.net
a dit ceci (said) :
>Paul J. Lindsey wrote:
>>
>> I'm researching attic fans to reduce my cooling bills. An installation
>> manual that I read at Home Depot said that if you had a gas furnace in your
>> attic, you needed an interlock switch so that the fan would shut-off when
>> the furnace came on. I'm guessing that it's so the combustion gases go up
>> the flue, not into the attic (carbon monoxide danger). Is this correct? I
>> also have a gas water heater in my attic, so I suspect I need an interlock
>> for it also.
>>
>> Anyone know exactly what these are (some sort of relay)? and where to get
>> them?
>
>
In theory, you would also need an interlock for the gas water heater. Most
good electrical stores would carry that kind of equipment. It is a relay
that would shut off power when there is some reduction in gas pressure
(hence : flow) in the gas pipe leading to your gas water heater.
Another simple idea would be to install a timer on the gas water heater.
This could be installed so that your water heater does not work in the
afternoon and during the night...
Another almost as simple idea would be to install two fans in a push-pull
type of arrangement. The fans would be of the same size and on the same
switch ; one taking in fresh air from the soffits and the other pulling it
out from the top.
Finally, if I were in your situation, I would isolate your water heater :
i.e. build a full enclosure around it, and install a 2, 3 or 4-in
air-supply pipe (depending on distance) to that room. That way, you would
cool the rest of the attic with your fan, and the water heater would be at
normal pressure.
P.S. Indeed, in Québec, water heater or furnace in the attic would have to
work with anti-freeze!
--
Michel Gagnon
mga...@total.net
Montréal (Québec, Canada)
Michael Lamb
Hi Paul and Michel,
My advice is DON'T DO IT!!! Attic power vents are at BEST a waste of money. If you want
lower cooling bills, air seal and insulate the attic floor. Paul, if you are in Canada
too, make it R-60.
Insulation works better, lasts longer, and doesn't use electricity. If you installed two
of these fan-things you can expect a higher electric bill. Research has proven that
attic fans use more electricity than they save in cooling bills. Fans are only
recommended when ALL other measures have failed.
No fan(s) also eliminates the need for interlocks (which are not easy to get to work
right anyway).
By the way, there is no such thing as a GAS water heater timer. A long time ago I
remember someone offering them, but as I recall they didn't work very well and were
quite expensive. They wouldn't make economic sense anyway. Gas is too cheap a fuel.
So, forget the fan(s)--air seal and insulate instead. Send me your mailing address and
I'll mail you some pubs on how to do this. This goes for anyone else who reads this
posting. What the heck, it's free!
ML .)