Extreme Cold+Propane Tanks: Advice Needed!

Hi Greenrvgreen,

Propane boils at -42.5 C.

I've used my RV at -37 C (-34 F)

I do have a tank heater--but have never had to use it. It is one of those stick on Magnetic heaters intended for use as a block heater.

If the tank is large I don't think it will be an issue. Large lines from the tank to the furnace should be used.

Are you using a propane generator?
Otherwise the flow rate is fairly small so stay above minus 30 degrees.

I would be far more concerned about my battery freezing as the charge is depleted.

Have only been down to about -10F.

Our LP furnace heated Adirondack cottage has kept us warm at -20? with no issues. And our LP fired coach furnace has kept us warm at -4? also with no issues. At the temps you're talking about, it should not be a problem. Keep in mind there are plenty of folks heating with LP in the northern states where even colder temps are pretty routine in the winter.

The gas flows fine at low temperatures; the problem comes from the propane boiling/evaporating in the tank, and there not being enough heat from the environment to keep up with the supply. (Well, also if it's cold enough the vapor pressure can fall too low.)

An LP generator needs a good bit more gas than most appliances and probably runs at a higher pressure. I would expect it to have trouble well before the furnace or stove. I might consider looking for a gasoline generator, some model that's known to start well in cold weather, assuming running a generator was generally a necessity. With sufficient solar, for instance, it may not be at most latitudes even during the winter. If you're in Fairbanks or some place like that solar would not be very much help during the winter.

Subzero, as in Fahrenheit, is too cold for me and my Winnie.

I lived FT in a 3 season TT for two Alberta winters.
There were a few times when it was around minus 34C that I had issues with my LP not flowing properly and my furnace wouldn't function properly. Due to it running a lot the flow was a lot higher.
There were a few times when I had to warm up my 2 30 pounders to make it flow.
I used a body heating pad, the one you use on sore muscles. I took the bottle cover off and put the pad between the bottles. It did the trick for me.
However, I did have a 15 amp plug in so I had 110 to run the pad with. You without hookups would have to find an alternate way to warm things up. As mentioned, batteries would be an issue. They would go flat in a hurry in those conditions.
If you are only into single digits below zero, it's not that big of an issue. Should be ok.
Then there's the water flow issues with pipes freezing..... That's another topic.

Propanes boiling point is as pianotuna said, -42 C, 44.3 f, There will not be any pressure or flow from the tank at temps below that.
In temps nearing those lows, only very large tanks, say 250 to 500 gal. tanks can boil off enough vapor to power a 35 k furnace. At minus 40 c or f its all the same,
' Bobs' trouble was due to small tanks that could not boil off enough vapor. fast enough.
Aint that right. Bob? , 'Tuna?
Your friend , been there, Max

The son in law has been spending winters in a fifth wheel either up on the Canadian border in North Dakota, or down in Wyoming where it hasn't been much warmer. Propane hasn't been an issue other than the quantities he burns through. A 500 gallon tank doesn't always get him through the winter without having to call for a re-fill.

In temperatures that low you'll have to do a lot of work to figure out the weak spots of your trailer and try to fix them to survive the cold. You'll most likely need skirting, a means of getting water into your tanks as you probably won't be able to keep hooked up to water all the time without troubles, and of course a means of draining without freezing the lines and fittings up. RV fridges are problematic when it's really cold, and of course if the furnace quits on you there isn't much time to take care of things before you run into freeze damage issues.

Quite doable, but can be an adventure.

You need a genset fitted out for liquid (not vapor) withdrawl, and the vaporiser as part of the genset and usually warmed by engine exhaust.
Art,

I'd suggest to try just the tanks and piping you have before going to any heroic measures.

I used to regularly fish on ice with just a conventional 20 lb cylinder and a rubber hose that ran to the inside of the fish house. Never had a freeze up problem. A larger cylinder (100 lbs.) will definitely eliminate any freeze problems, especially if there is no water inside the regulator or lines.