lp tank losing pressure in the cold.

[Jonathanpitzl]

I have a 24’ trailer that I put a 40k suburban forced air furnace in. I mounted the lp tank outside by the hitch. Last year I was have problem on cold nights with the lp tank loosing pressure. What do you guys do to keep the tanks warm enough to where they don’t loose pressure? I’ve seen heated blankets. Thanks in advance!

 

[Ox]

Well, you may need to define "cold" nights, but for the record, LP is said to stay liquid at about -40*, so the closer that you git to that number, the less evaporation that you will git. This is why most wintering tanks are "lay down" tanks, as that allows much more evaporative surface in the same size tank.

I don't know if they offer lay down tanks that are of camper size?
But I think that you could git away with a 120gal tank if it came to that.
I think that is the largest tank that you can legally move when full.

Another option is if you could tie 2 or 3 40# tanks together?
I have seen this done on larger (V-8) fork-trucks, but those draw liquid, not vapor, so not 100% sure that it would work, but I don't see why not?
This would get your surface area up to a point that might not choke?

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[IDspud]

I have had a tank quit releasing at -10, two hours in cabin started working again, four hours outside quit again.
Solutions would be good to hear.

 

[mysledblows]

While I’m sure there are all sorts of reasons not to do it, we had a trailer for years that had the tank inside in the nose. Never had any issues with it and the guy that has the trailer still runs it that way.

 

[IDspud]

If it expands and vents as designed your trailer is the perfect bomb.

 

[High Voltage]

It isn’t always the tank. The pressure regulators can get moisture in them, and freeze up the whole operation. Fishing in subzero temps in northern MN many fishermen that stayed in their fish house during deadly cold snaps would have a couple regulators so they could thaw out a frozen one. They also would wrap fiberglass insulation around them.

 

[Teth-Air]

Don't forget that even if it is -10 outside as the propane phase changes from liquid to gas it requires heat so it takes it from its surroundings and further cools the tank. If you insulate the tank it can be colder than the outside air temperature. Warming the tank may not be practical though and many don't have an issue so maybe your regulator is freezing up and restricting the gas flow? It would only take a few ice crystals to do this. Do you ever leave the valve open on an empty tank that moist air could have got inside the tank? If the problem is the tank is getting too cold you might have to use 2 tanks at the same time so there is less phase change going on in each tank and therefore less cooling from evaporation.

 

[IDspud]

Is there a king of regulators for preventing this?

 

[Ox]

I don't understand how insulating the reg helps?
There is no heat source.
And actually, you could be insulating it FROM the ambient air, which - although cold - still is likely warmer than the unheated reg is once it is dooing it's job.

No ???


Maybe put the reg in the trailer?
I'm shirley not above puting the whole inside either.
If it git's warm enough to vent off - especially from a tank that is being drawn from, then the trailer is on fire, and you already have other troubles.

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[High Voltage]

Not sure if putt insulation around the regulator does any good. Might give you warm fuzzies though. ?

 

[turbolover]

While I’m sure there are all sorts of reasons not to do it, we had a trailer for years that had the tank inside in the nose. Never had any issues with it and the guy that has the trailer still runs it that way.

That's where mine is. Might be a bomb but I'll probably go up with it. So then it becomes someone else's problem at that point.

 

[chickenstixx]

I have a 24’ trailer that I put a 40k suburban forced air furnace in. I mounted the lp tank outside by the hitch. Last year I was have problem on cold nights with the lp tank loosing pressure. What do you guys do to keep the tanks warm enough to where they don’t loose pressure? I’ve seen heated blankets. Thanks in advance!

best thing is to daisy chain a few tanks together. there is a limit of BTU energy a tank can provide in the cold. Look at the attachment. A 40k btu heater will pull too much, "freezing" the tank.

 

[IDspud]

Believe you just identified my specific issue.

 

[Wheel House Motorsports]

Some pretty quality info on this thread, as mentioned, although propane doesnt stay in liquid phase until -40* it barely is evaporating at much below 0. insulating any of the tank/regulator components etc would have the opposite affect. the tanks need to absorb heat energy from the outside air in order to keep evaporating. Even those silly little RV style covers are going to be working against you. Larger tanks, (30 or 40#) would also help as they are going to have a bigger thermal mass so it can help absorb/dissipate heat a tiny bit better. These are both VERY small changes though compared to more tanks.

As mentioned above, the simplest and safest solution is more then 1 tank hooked together all active at the same time to reduce the BTU draw from each tank. This will allow the heater to rock at a full blast down to much lower temps without issue.

 

[IDspud]

So how stupid is it to route furnace exhaust for heat into bottle cabinet that’s airtight in direction of trailer interior, open out bottom?

 

[Ox]

Some pretty quality info on this thread, as mentioned, although propane doesnt stay in liquid phase until -40* it barely is evaporating at much below 0. insulating any of the tank/regulator components etc would have the opposite affect. the tanks need to absorb heat energy from the outside air in order to keep evaporating. Even those silly little RV style covers are going to be working against you. Larger tanks, (30 or 40#) would also help as they are going to have a bigger thermal mass so it can help absorb/dissipate heat a tiny bit better. These are both VERY small changes though compared to more tanks.

As mentioned above, the simplest and safest solution is more then 1 tank hooked together all active at the same time to reduce the BTU draw from each tank. This will allow the heater to rock at a full blast down to much lower temps without issue.

" For example if we look at table #1 we can see that if we had a bucket full of liquid propane and the temperature was below -44 degrees Fahrenheit the propane would remain a liquid at normal atmospheric pressure."

Propane Facts & LPG

Propane Comparison Charts and Facts about Propane, including fuel properties and propane pressure versus temperature chart, and other general information about propane.

centuryfuelproducts.com

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[High Voltage]

So how stupid is it to route furnace exhaust for heat into bottle cabinet that’s airtight in direction of trailer interior, open out bottom?

You would have alot of moisture and probably create more issues. If you are running a generator they make electric wraps to put on tanks to heat them.

 

[zal]

When I had my rv sled camp and it was colder than -20°C, I would grab a tarp or a welding blanket and throw it on top of the tanks to cover them completely. Then I would put a space heater inside with the tanks to keep it warm. Never had an issue. It’s also an option.

 

[chevy_man]

I just set the tanks in front of the heater. Keeps the pressure up and you can use the full tank.


Again, if something goes really wrong I'm not going to have to deal with it. It'll be someone else's problem at that point and my life insurance is good for accidents, even caused by my own doing.

 

[richracer1]

I have a 24’ trailer that I put a 40k suburban forced air furnace in. I mounted the lp tank outside by the hitch. Last year I was have problem on cold nights with the lp tank loosing pressure. What do you guys do to keep the tanks warm enough to where they don’t loose pressure? I’ve seen heated blankets. Thanks in advance!

My sled trailer came with an RV style tank mounted to the frame. It work great for quite a while. I started having issues with getting it to remain burning. It turned out to be the regulator went to crap and would cut off the propane flow. A new regulator fixed the problem. My point is, there may not be an issue with propane pressure but instead you may a regulator that has failed.