Tankless water heaters in RV
Peter Pan
both propane and electric, and don't keep water hot when not being used.
Seems great for houses (this one is sold for vacation houses/cottages), but
I have never seen one in an RV before.
The one I am considering is an electric/propane model, that allows use when
hooked up (electric), and when boondocking (propane). They also have an
optional heat exchanger that can be used in the air box with a furnace
blower air/ducts etc to warm the air in the RV without running the furnace
burner.
It's meant for a fixed installation in a cottage, but if movement won't harm
it, and it's feasible to put in an RV, it sounds almost too good to be true.
Anyone have any thoughts/stories etc on the subject?
GBinNC
<Pete...@NEVERNEVERLANDNOSPAM.sc.rr.com> wrote:
>My Water heater died, and I am looking at the tankless systems that run on
>both propane and electric, and don't keep water hot when not being used.
><snip>
>It's meant for a fixed installation in a cottage, but if movement won't harm
>it, and it's feasible to put in an RV, it sounds almost too good to be true.
>Anyone have any thoughts/stories etc on the subject?
I don't know about for an RV, but I did some fairly extensive research
not long ago on the idea of putting one in my house.
I ultimately decided not to, for a variety of reasons. One of them was
that I didn't like the idea of the burner coming on every time I
wanted to run just a small amount of water to wash my hands or
whatever. Every time you open a hot water faucet, the burner switches
on. And it uses a LOT of propane.
Temperature is "reverse-dependent" on water flow. If you partially
close an open hot water faucet, the water gets hotter; open it again
and the water gets cooler. That anomaly would drive me crazy (well,
okay, crazier <g>).
I also came to the conclusion that it works better if you're a "heavy
water user" -- which seems counter to the norm in RV applications...
GB in NC
one@home.com Wade
"Peter Pan" <Pete...@NEVERNEVERLANDNOSPAM.sc.rr.com> wrote in message
news:8Fk59.3753$iP2.1...@twister.southeast.rr.com...
fired one, only seen on diesel pushers, and it will cost you considerably
more then any propane fired unit.
Wade
one@home.com Wade
"GBinNC" <GBi...@yahoooo.com> wrote in message
news:q5mbluccab777d2qh...@4ax.com...
> On Sun, 11 Aug 2002 03:15:16 GMT, "Peter Pan"
> <Pete...@NEVERNEVERLANDNOSPAM.sc.rr.com> wrote:
>
>> I don't know about for an RV, but I did some fairly extensive research
> not long ago on the idea of putting one in my house.
>
> I ultimately decided not to, for a variety of reasons. One of them was
> that I didn't like the idea of the burner coming on every time I
> wanted to run just a small amount of water to wash my hands or
> whatever. Every time you open a hot water faucet, the burner switches
> on. And it uses a LOT of propane.
>
> Temperature is "reverse-dependent" on water flow. If you partially
> close an open hot water faucet, the water gets hotter; open it again
> and the water gets cooler. That anomaly would drive me crazy (well,
> okay, crazier <g>).
>
temperatures you need what is called the mixing valve to maintain constant
140 degrees, and you are right by itself it is to much trouble, in our case
we have the gas fired boiler that supplies the hot water and heats the pool
via exchanger, as well as central hot water heat for the house.
Wade
Mo
how much hot water (gal/min) it produces.
I checked on these a few years back and the output was low and the elec.
draw was enormous to heat water that quickly.
Mo
"Peter Pan" <Pete...@NEVERNEVERLANDNOSPAM.sc.rr.com> wrote in message
news:8Fk59.3753$iP2.1...@twister.southeast.rr.com...
Peter Pan
water heaters, a propane one for boondocking and high use situations (3.2
GPM max and about $400 bucks), and an electric under sink unit for use when
in a site (1.5 GPM max for the kitchen/bathroom sinks only <but not for the
shower> under $180). Consider the under sink unit to be an in site only
unit, and only active when plugged in and electrical shore or generator
power is available, otherwise, it's inactive. It uses about 29 Amps when in
use. If showering in the RV while in site, the propane one has to be used.
If washing dishes/hands etc while in site, the electric one is used. When
boondocking, only the propane one is used for all uses. If at an RV park,
using their showers, only the electric water heaters for the sinks are
usually used.
My understanding is that a replacement Atwood gas water heater with tank is
about $400, and a hot rodd about $100, so for about $80 more, I can have on
demand rather than tank based hot water.
Like I said, I don't know if it will work OK or not (especially in an RV),
but considering how much I used to spend a year for propane just for heating
water, it seems like it would pay for itself.
Oh, the other piece of information, I fulltime in my RV and would love to
have hot water when needed without heating it 24/7.
"Mo" <mo_drew...@yahoo.com> wrote in message
news:CGm59.127239$Ag2.6...@news2.calgary.shaw.ca...
Tom
I looked at the tankless heaters. The temperature will swing when using a
medium flow rate. The tankless heaters are a solution looking for a problem.
As pointed out, the pilot light keeps the water hot. In my opinion that's a
good thing.
Tom
Chris Bryant
The only tankless water heater I know of which is approved for
RV use is the Precision Temp RV500 - http://www.precisiontemp.com/ .
It is LP only (the electric requirements would be substantial)- but it
does a very good job. It uses a flow sensor and a modulating gas valve
to regulate the temperature of the water independent of flow.
--
Chris Bryant
Bryant RV Services- http://www.bryantrv.com
Neon John
<Pete...@NEVERNEVERLANDNOSPAM.sc.rr.com> wrote:
>Maybe I should have been a tad bit clearer. There are actually two on demand
>water heaters, a propane one for boondocking and high use situations (3.2
>GPM max and about $400 bucks), and an electric under sink unit for use when
>in a site (1.5 GPM max for the kitchen/bathroom sinks only <but not for the
>shower> under $180). Consider the under sink unit to be an in site only
>unit, and only active when plugged in and electrical shore or generator
>power is available, otherwise, it's inactive. It uses about 29 Amps when in
>use. If showering in the RV while in site, the propane one has to be used.
>If washing dishes/hands etc while in site, the electric one is used. When
>boondocking, only the propane one is used for all uses. If at an RV park,
>using their showers, only the electric water heaters for the sinks are
>usually used.
I'm a big fan of tankless heaters and own a number of them. A few thoughts.
I use the electric tankless heaters in the bathrooms and handwashing sinks in
my restaurant so that there will be instant hot water. These little heaters
draw about 28 amps at >> 240 volts <<. Even with that considerable electrical
draw the heaters really don't do that good a job in the winter when the
incoming water is cold. The heater has a cold weather orifice that restricts
flow to a bit under 1 gpm - annoyingly low. One CAN wash his hands in this
small bit of water but I'd not want to attempt anything more extensive.
In an RV this sort of unit could only be used with 50 amp hookup or from a
large generator. I would not consider that to be practical unless you spend
all your time in parks with 50 amp service.
For my main source of hot water in my restaurant and attached apartment I have
installed this unit:
http://www.tanklesswaterheaters.com/palomaph24m.html
You'll notice that even with an energy input of 178,000 btu, this heater can
heat just under 3 gpm to a 100 deg rise. This ranges from adequate in the
winter to great in the summer. This unit is physically about the size of a 30
gallon drum - much too large for an RV.
Paloma makes several smaller units. I previously had this model:
http://www.tanklesswaterheaters.com/palomaph12m.html
In the restaurant and currently have one in my cabin and another in my parents
house. This heater is adequate for residential use if you use a water saver
shower head but cannot supply enough water in the winter for a good high
volume shower. This unit is a little larger than a 5 gallon gas can - still
too large for an RV.
This unit might work in an RV:
http://www.tanklesswaterheaters.com/palomaph16fs.html
but it does require 120 vac to operate.
Paloma used to make a small unit designed for marine and RV use (I've seen
them on house boats) but I can't find a listing for it anymore. Judging from
the size of the burner in the ones I've seen vs the units I own, I doubt that
it could supply enough hot water for a comfortable shower in the winter and
would probably push things in summer.
>My understanding is that a replacement Atwood gas water heater with tank is
>about $400, and a hot rodd about $100, so for about $80 more, I can have on
>demand rather than tank based hot water.
>Like I said, I don't know if it will work OK or not (especially in an RV),
>but considering how much I used to spend a year for propane just for heating
>water, it seems like it would pay for itself.
>Oh, the other piece of information, I fulltime in my RV and would love to
>have hot water when needed without heating it 24/7.
I've wanted a tankless solution in my rig since they work so well in my
facilities but so far I have not found a practical solution.
John
---
John De Armond
johngdDO...@bellsouth.net
http://personal.bellsouth.net/~johngd
Cleveland, Occupied TN
Neon John
><< Save money by buying the least expensive water heater that will fit. >>
>
>I looked at the tankless heaters. The temperature will swing when using a
>medium flow rate.
No. At least that's not the case with a quality heater. The Palomas all have
proportioning valves that vary the firing rate with water flow. Very good
temperature regulation. Paloma is the only brand I have personal experience
with. According to what I read on the web, some other brands with electronic
controls do the same thing. Only the cheap heaters fire at one fixed rate.
>The tankless heaters are a solution looking for a problem.
Well, I don't know if these qualify as "problems" or not but I have several
items that the tankless heater addressed. One, I like to take long, hot
showers on occasion. Two, I like to be able to shower or bathe during or
after I run a few loads of clothes in the washer. Three, I like to use hot
water with my pressure washer when I'm washing an engine compartment,
degreasing car parts, etc. At 5 gpm, a 40 gallon tank is drained in 8 minutes
or so. Four, in my restaurant I have sinks that hold 50 gallons of water
each. My dishwasher needs to fill both with hot water for each batch of
dishes. A tank heater capable of supplying that much hot water at once is
very expensive, is far too large to fit in the space available and has a
relatively huge quiescent energy loss. Five, At my cabin, which I don't visit
very often anymore, it would be foolish to keep a water heater on all the
time. Yet I usually get there late and immediately want to take a shower. I
do NOT want to wait for a tank heater to heat up. Six, My mother's antique
shop is similar - very seldom is the shower in the back used but when it is,
no one wants to wait for a tank heater to do its thing. Seven, If I ever buy
an RV with a shower large enough to use, I'll want to take long hot showers
there too.
Now I suppose we can quibble on the definition of "problems" but these were
certainly problems to me, problems that the tankless heaters solved.
>As pointed out, the pilot light keeps the water hot. In my opinion that's a
>good thing.
Yep, and a pilot light will suck down a tank of propane in literally days, at
least mine will. The tiny, almost invisible standby pilot (a larger pilot
lights when water flows) in my Paloma uses almost no gas.
If you're happy with a whimpy RV water heater, then it is serving your needs.
Some of us have different needs.
John
---
John De Armond
johngdDO...@bellsouth.net
http://personal.bellsouth.net/~johngd (old)
http://bellsouthpwp.net/j/o/johngd/ (new)
Cleveland, Occupied TN
Tom Marik
My comments were based on the PrecisionTemp products. They are great at providing
3 to 5 GPM continuously. If someone opens another faucet at 3 GPM, that shower
will get cool. Not ice cold but cool.
I have to admit that your long shower luxury is the ideal use of a tankless
system. Just as long as nobody tries to run the dishwasher and laundry at the
same time.
Tom, happy with three minute showers.
Charles Callaghan
campsite will be able to give you. If you can find one at 120V then I would
be very careful not to run anything else in the trailer, like AC. the
instant heaters use a lot of juice, be careful.
"Tom Marik" <tom....@oracle.com> wrote in message
news:3D62B335...@oracle.com...
Tom Marik
PrecisionTemp is propane with only electronic controls. On high it has a 53,000
Btu (per hour) input. It provides about five gallons per minute of warm water.
You're right in that an electric unit would need the whole 12 kilowatts to come
close to doing the job.
John, could you mention the capacity of the Paloma system?
Tom
Technobarbarian
> John, could you mention the capacity of the Paloma system?
It depends on the model you select. Their largest model will heat 171
gallons/hour100°F rise. http://www.tanklesswaterheaters.com/palomaph24m.html
Dennis
Tom Marik
Gulp! Seven inch vent! 178,000 BTU per hour!
But even with that, they are talking about one shower head only or dishwasher or
clothes washer. It's a lot of hot water but it still requires cooperation.
Bart Simpson would have a ball with Homer taking a shower.
Tom
Neon John
>Charles,
>
>PrecisionTemp is propane with only electronic controls. On high it has a 53,000
>Btu (per hour) input. It provides about five gallons per minute of warm water.
>
>You're right in that an electric unit would need the whole 12 kilowatts to come
>close to doing the job.
>
>John, could you mention the capacity of the Paloma system?
The PH24m that I use in my restaurant and apartment is specified to deliver
2.85 gpm @ 100 deg rise, 5.7 gpm @ 50 deg rise. The burner input is rated at
from 37,700 to 178,500 btu/hr.
The PH12m that I have in my cabin and my mother's antique store is rated at
1.43 gpm @ 100 deg rise, 2.85 gpm @ 50 deg rise. The burner input is rated at
from 30,000 to 89,300 btu/hr.
One has to watch the specsmanship games mfrs play. Quoting a delivery rate
without quoting the temperature rise is meaningless. If precisiontemp is
quoting a 5 gpm flow rate with only 53,000 btu/hr input, it can only be
heating the water maybe 25 deg. In the winter when the water inlet is in the
38 deg F range, that isn't enough for bathing. I found the PH12m to be on the
edge of inadequate in winter with the old fashioned high flow shower heads we
use. It would be OK with a water saver but that kinda defeats the benefits of
a tankless heater :-) That's why I went with the PH24m.
One feature I really like is that the Paloma does not need power. The gas
proportioning valve is entirely mechanical. A diaphragm connected across an
orifice in the water line measures water flow. This diaphragm operates the
gas valve. Works even during a power outage and there's no microprocessor
board to get zapped by lightning. The only complaint of have of the Paloma is
that the standard neoprene diaphragm only lasts about 2 years in our grossly
overchlorinated water here in Cleveland. Paloma tells me that they have a
teflon diaphragm available but I've yet to be able to order one. I simply
keep a couple of spares on hand and change 'em when they rupture.
I got my specs for the Palomas here:
http://www.tanklesswaterheaters.com/palomaheaters.html
Never dealt with these folks but they have good web pages :-)
Neon John
>Dennis,
>
>Gulp! Seven inch vent! 178,000 BTU per hour!
>
>But even with that, they are talking about one shower head only or dishwasher or
>clothes washer. It's a lot of hot water but it still requires cooperation.
>Bart Simpson would have a ball with Homer taking a shower.
Not that bad. I can shower with the washing machine running and never know
the difference. Remember that you mix cold water in with the hot for your
shower so the flow from the water heater is lower than you'd at first think.
The paloma at full chat can deliver 180 deg water so it takes only a little
hot water to make a shower juuuust right. The heater has a knob on the front
where you can set the temperature rise you want.
A 7" vent can be used but it isn't necessary. The flue connection has several
concentric rings for different vent pipe connections. I used standard 6"
stove pipe on mine because it was handy. It feeds about 2 feet into an old
coal stove chimney thimble. The chimney liner is about 6 inches square. I
can fairly comfortably lay my hand on the flue with the heater at full power.
It is quite efficient.
Since a picture is worth a thousand words, I put a picture up of the PH24m in
my restaurant.
http://bellsouthpwp.net/j/o/johngd/files/rv/Paloma_PH24M.jpg
Several things to note. First, it just hangs on the wall like a cabinet in
otherwise useless space. No floor space is used. One can get a size scale of
the unit by the 1 gallon jugs at the bottom of the photo. If you zoom in on
the flue, you can see the unused 7" attachment ring. I use high pressure (2
psi) gas distribution in my place. The small regulator under the heater
reduces the pressure to standard natural gas pressure at the point of use.
The top knob turns it on and off and fires the piezo igniter. The bottom knob
sets the temperature. The whole front lifts off after removing two thumb
nuts.
Technobarbarian
> Dennis,
>
> Gulp! Seven inch vent! 178,000 BTU per hour!
They make smaller units. Most of us don't need to heat 171 gallons/hour
100F heat rise. I think my little Paloma was the smallest they made at that
time and it's just fine for long hot showers.
> But even with that, they are talking about one shower head only or
dishwasher or
> clothes washer. It's a lot of hot water but it still requires
cooperation.
> Bart Simpson would have a ball with Homer taking a shower.
As Neon John notes, this is not the case.
Dennis
Tom Marik
I didn't snip anything because your explanation isn't easily condensed.
Would you build this into a closet with exterior access as opposed to a basement
heater?
Were you planning on that capacity for the RV?
Once again, the PrecisionTemp is roughly a third of that capacity of the Paloma. It
was the PrecisionTemp that I said wasn't a total solution.
Tom