What temp causes propane to stop flowing properly?

[Wobbles]

What temp causes propane to stop flowing properly? Just thinking about camping where it is really cold. Any worries about the furnace being able to perform? I am talking about a TT with the bottles out front.

[KenHwy61]

Propane has a boiling point of -43 degrees so you should be good unless camping in Antarctica!
My house furnace runs off a propane tank and works fine in sub-zero temps.

[Fluffywhitedogs]

Thanks Wobbles for asking, and Ken for the reply!

[Wobbles]

Originally Posted by KenHwy61

Propane has a boiling point of -43 degrees so you should be good unless camping in Antarctica!
My house furnace runs off a propane tank and works fine in sub-zero temps.

Thanks, I know homes have had this going on forever. I have had a 20lb bottle give me trouble when it was cold and seem to work ok after the temp went back up. Perhaps the trouble was with my equipment that I was connecting too.

[BendOrLarry]

We had a tank regulator freeze up one trip when it was 12 below zero F. Warmed up the regulator and all was good.

[Evereddie]

Originally Posted by Wobbles

What temp causes propane to stop flowing properly?

When it is sooo cold your hands can't turn on the valve! There is no propane flow then.

[gasman6674]

Btu capacity is influenced by ambient temp ,size and volume of tank. For example:
a 20# cylinder 25 % full at 20 degrees will only produce 13,000 BTU a 40# cylinder under the same conditions will produce 21,800 so keep them warm and keep them full.
pressure wise at Zero degrees the tank pressure would be 28-30 psi at 20 degrees it would be 47 psi.

[Happy Camper 2715]

X2,What Gasman said.

[frozen]

Up here in northern Minnesota -30 F isn't real uncommon, and in the old days before the weather changed, -40. A lot of us heat our homes with propane and it keeps on flowing. During the two -50 nights that I survived many years ago, fuel oil congealed. Anyone who camps in those temperatures has a lot better rig than mine.

[DSQR]

1. Propane in the tank/cylinder must vaporize before it can "flow"
2. Normally, if container has not been providing vapor recently, it will be at ambient temperature.
3. As you begin taking vapor from container, the liquid in the container vaporizes and cools. As the liquid coola, pressure within the container goes down.
4. To keep the container pressure up, heat must flow into the cooling liquid. This heat flows primarily through the wetted walls of the container - walls contacting only vapor have a negligible effect. There's a lot more wetted wall when the container is 80% full than when the tank is 20% full.
5. The more wetted area (the fuller the container), the more heat flows in, and the faster vapor is produced. (DO NOT insulate a propane cylinder - this works against you by keeping heat from flowing into the container!)
6. LP appliances require about 1/2 psig (11 inches water column) of pressure. A tank at about -40 degrees F will have this pressure. But if you start removing vapor from this tank - reread 4 and 5.

A larger container provides more wetted area than a smaller tank it can keep the vaporization rate up. A 20# cylinder 80% full will have more wetted area than a 30# cylinder which is only 40% full, and the 20# cylinder will be, at this condition, able to provide greater vapor flow.

Remember - it is vapor coming from the tank, not liquid. (This statement is not true for tanks used with generators or other propane motor equipment).

[MOODMAN]

Just a thought, but if you are concerned about it, you could put your propane tanks in a heated compartment.

[dahagen]

Remember that sometimes water gets into the propane system and that freezes at 30 degrees F.

[bplantcjf]

In some places they may add butane to the propane in warm weather areas. Butane boils at 33 degrees F. If you are unfortunate to get a mixture when it is warm it may not vaporize at very low temps. You can also get moisture in the tank which can freeze in the regulator causing no flow.

[Tom48]

[QUOTE=Wobbles;1100138]What temp causes propane to stop flowing properly? Just thinking about camping where it is really cold. Any worries about the furnace being able to perform? I am talking about a TT with the bottles out front.

[/quote

I FLY A HOT AIR BALLOON and at temps dropping towards zero it works fine but flow rate for our 12,000,000 btu burners is sometimes too low. Should not be a problem for a 30 000 btu burner.

I have heard of valve or regulator freezing up ,but am told that comes from moisture in a tank and the tank needs to be purged and flushed (I think they use alcohol for that). BUt as quick fix a hot towel or cautious use of a hair dryer will normally get it working again.

[DSQR]

If you are thinking about putting your propane container in a heated compartment -
Code prohibits propane containers in closed, non-ventilated spaces. Propane, being heavier than air will accumulate in the space - or any low spot.
Water in propane systems generally a result of leaving lines or empty tanks open to the atmosphere. Ever leave a cylinder valve open while it's "empty"? Ever leave a propane line open with the tank removed?

[Canadiancrew]

The only thing I found out through ice fishing is that cold air is more dense than warm air. The propane performs just the same unless you get moisture that freezes up your regulator. My cook stove and burners will not light and quit working somewhere below -5 and definitely will not light at -40. Turns out that is due to the density of the cold air not the propane. I could actually get my little single burner cook top to light if I blocked the air flow at the little device under the burner that mixes the air with the propane. This results in burning pure propane with no air mix. Interesting though is my mr heater propane heater works great in my portable ice hut. I am not sure why or how it mixes air but it works great at those temps.

So how this applies to an rv I am not sure. I would say it is going to depend on the individual appliance. I would suspect the water heater would not work as it uses that same Venturi air mix thing. The furnace??

I found the following explanation on air density:

When air becomes hot it is because it is absorbing energy in the form of heat. The absorbed energy makes the molecules in air move and expand, therefore decreasing the airs density. The opposite is true for cold air. It is more dense because the molecules are closer together and they are closer together because the bonds are absorbing less energy and therefore do not move as much.

[DSQR]

Propane is only flammable when it is mixed with air to provide a propane/air mix between about 2% to 10%.
Pure propane will not burn.
The density of air only changes about 10% between a temperature of 60F and 0F.

[Canadiancrew]

Originally Posted by DSQR

Propane is only flammable when it is mixed with air to provide a propane/air mix between about 2% to 10%.
Pure propane will not burn.
The density of air only changes about 10% between a temperature of 60F and 0F.

Only stating what I have seen multiple times. The propane burner will not light at -40 unless the air intake is blocked. Ok maybe it's not pure propane likely still getting some air.

The density changes is enough to effect the operation of a portable burner/stove. The same is true with butane. A friend that winter camps in the bush uses white gas or alcohol burners for this reason.

[gasman6674]

FYI
Your still getting secondary combustion air at the surface of the burner

[Canadiancrew]

Originally Posted by gasman6674

FYI
Your still getting secondary combustion air at the surface of the burner

Yes that would make sense.

Anyway I did some research and found this on ehow. My conclusion is that at the -40 I spoke of it may be more of a low pressure issue than air density.
Anyway who is going to use an rv at those temps. You will have bigger issues than propane to deal with. I don't even like to ice fish at that temp. Only happens when we have a trip planned and the weather turns on us. At -20 you can work with stuff. At -40 I do not want to try fixing anything like a skidoo that won't start.

From ehow:

Similarities Between Propane and Water
Liquid propane and water act similarly when temperature drops, but their boiling points differ. At sea level, propane begins to boil at a temperature of -44 degrees Fahrenheit and produces propane vapor, while water boils at 212 degrees F and produces water vapor. As the temperature drops below 212 degrees F, water stays in liquid form, it doesn't change to a vapor. Similarly, as the temperature outside the propane tank drops and approaches -44 degrees F, less propane boils inside the storage tank producing less vapor and a lower pressure.

Critical Temperature
As the pressure inside the propane tank drops, it eventually becomes too low to light a furnace or other appliance. At -44 degrees F or lower, propane stays as a liquid, there is little vapor and propane appliances won't function properly. Therefore, for appliances to work correctly, a propane tank must usually be kept in an area with a temperature greater than -44 degrees F.