Propane boiler ?

550Doug · Jan 29, 2018

I'd like a backup heating system for a house and am looking into a hot water radiator system powered by a propane boiler. Is this possible or even reasonable for temps down to -40F?
Can an in-floor system using pex run off a boiler?
Thanks for any comments

Butch. · Jan 29, 2018

I wouldn't even bother looking.
Sell the house and move. lol

47fivewindow · Jan 29, 2018

I asked this question of my furnace guy, and he said yes, but the boiler would have to run a seperate heat exchanger before it went into the pex to lower the temp. I'm no expert but have been told it can be done.

Brendon Warren · Jan 29, 2018

I heat with an oil fired boiler. I have pex in floor hooked to it downstairs. It has a mixing valve on the in floor loop. The baseboard upstairs and water heater do not. I also have a wood boiler hooked to it and it has a heat exchanger. Mine would have trouble keeping up at -40? but I think that is more to do with how tight my building is and I could stand to have more baseboard.

David G · Jan 29, 2018

Yes, that is a very nice heating system, and can your primary heat.

What is your primary heat?

I like hot water heat.

Roger Tomfohrde · Jan 29, 2018

-40 ? seems like a unusually low temp. The manuals for sizing of heat loads are based on the area heated and the insulation of the structure. Boilers using higher water temps than 125 degrees F will not
condense. So a load calculation would need to be done in any case.. It is all about how many BTU's need to be used. Oil boilers typically run very high because of the btu content in the oil is around 165,000
per gallon. Propane is 92000 per Gal and natural is less. Usually they are sized so there are a couple days where the boiler will run continuously at the low temp. Otherwise they are drastically over sized In
Minnesota. A load calculation by a reputable person will show if it can be done. So in short maybe and maybe not.

farmerwithmutt · Jan 29, 2018

My new system is a infloor heat run off
boiler. I'm using electric instead of
propane . It seems cost effective the
problem i see with propane is you have to
book early and even that can be questioned
it depends a lot on the corn harvest in the
fall and how available it is. A second thing
is installing with propane i need a tank in
the yard pipe it into the house regulator
and vent system. There is also a rebate with
electric. Northern tool has a sale on
boilers right now but make sure there big
enough. If you put infloor in you will need
to insulate the walls and floor plus put
plastic in.

buickanddeere · Jan 29, 2018

It may hit -40F in Guelph every 25 years . 0F is on the low end for normal winter day with temperatures in the teen’s and 20’s more common.
No natural gas supply ?

ffreeb · Jan 29, 2018

-40F is very close to the boiling point of propane.

You may have to put a heater on the tank.
Propane 101

Roger in Iowa · Jan 29, 2018

Backup for what? Another type of system? Power outtage system? Boiler systems still have to have electric power to
circulate the water??

Bob · Jan 29, 2018

(quoted from post at 18:57:05 01/29/18) -40 ? seems like a unusually low temp. The manuals for sizing of heat loads are based on the area heated and the insulation of the structure. Boilers using higher water temps than 125 degrees F will not
condense. So a load calculation would need to be done in any case.. It is all about how many BTU's need to be used. Oil boilers typically run very high because of the btu content in the oil is around 165,000
per gallon. Propane is 92000 per Gal and natural is less. Usually they are sized so there are a couple days where the boiler will run continuously at the low temp. Otherwise they are drastically over sized In
Minnesota. A load calculation by a reputable person will show if it can be done. So in short maybe and maybe not.

GOSH, Roger, I don't know what you are smoking to come up with a BTU content of "furnace oil" @ 165,000 BTU/gal (standard # for #2 is 134,000).

As to your assertion that condensing boilers can't work over 125º that's also completely BOGUS.

OUTPUT boiler temp has nothing to do with the condensing process, it's the temp of the return water that counts, and there's various ways to deal with that so the condensing process can occur.

Also, I CHALLENGE you to show us a "gallon" of natural gas!

Roger Tomfohrde · Jan 30, 2018

As to over 125 degrees the moisture no longer condenses and it goes out the exhaust turning a 90 percent eff. boiler into a 80 percent because the heat is not recovered in the heat exchanger, so to do what you are suggesting you have to add on to a normal boiler(of course I have been out of the business for ten years and things can change). Yes my mind is operating on some very old data, sorry, 138000 is some what better but you would still need to check the vendor. Nat gas is measured by Therms which is in cubic feet. Roughly a 1000 btu. per cu foot whereas propane is 2500 for the same volume. You can compress nat. gas to get gallons and there is some heavy equip in MN that use it, and there are places to sell it for use but I do not know the btu. content of that;-)My only point I was trying to make is oil usually is used where OAT temps are colder, which is a regional thing.

rrc300 u · Jan 30, 2018

Most comments are correct. You will
like the floor heat,I promise that.
The best bet is to find a reputable
hot water heater installer. Probably
is not going to be the outdoor boiler
guy,or the local plumber,it could be
but I would guess not. Interview the
contractor and ask for pictures to
show some of his work on a project
like yours. The process that you want
to do is possible but it is alot more
involved than a basic boiler swap.

Ozlander · Jan 30, 2018

(quoted from post at 21:12:03 01/29/18)
Also, I CHALLENGE you to show us a "gallon" of natural gas!

It's LNG (Liquefied Natural Gas)
That's how they ship it.

Craig45 · Jan 30, 2018

Had hot water base board heat in one house we had. Always worried the the power would go off in the dead of winter and the pipes would
freeze.

Propane boiler ?

550Doug

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Butch.

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47fivewindow

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Brendon Warren

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David G

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Roger Tomfohrde

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farmerwithmutt

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buickanddeere

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ffreeb

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Roger in Iowa

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Bob

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Roger Tomfohrde

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rrc300 u

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Ozlander

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Craig45

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