I have run into a problem due to low temperatures. At some point below freezing, something is freezing up and not allowing me to use anything that uses gas. The tech turned on the stove and after about 15 seconds with an electric match, the front burner lit. I thought he had overridden something but he said it was due to warmer temperatures. He added it might be a problem anywhere from the LPG leak sensor inside the door, to a relay at the tank. Concerning the LPG sensor, if that was the problem, he said it would be the wires coming from the unit toward the tank.

My question: is there a "fix" to keep it, whatever the culprit is, from freezing up?

It's possible your pressure regulator is freezing up from stray moisture in the system. It has happened to me. There was no moisture visible anywhere, but a new regulator with a built-in housing cured the problem.

Propane works by boiling - the transformation from a liquid to a gas. At temperatures below 32 degrees it does not boil and thus you get no gas. Heating the tank will solve this problem and one way to do so is to wrap the tank with an electric heater tape (http://plumbing.hardwarestore.com/52-299-heat-tape.aspx) and operate it from your shore power or generator. It can be installed by cleaning the tank sides and bottom and using a good adhesive to hold it in place. You can connect to a switch to turn it on or leave it as a cord plug and manually use it.
Tom

quote:

Originally posted by Tom K:
Propane works by boiling - the transformation from a liquid to a gas. At temperatures below 32 degrees it does not boil and thus you get no gas.

The boiling point of propane is closer to 44 degrees BELOW zero or -44f. Propane, as Tom pointed out, is a liquid. We use the vapor and take from the gasses that gets boiled off to light our furnace and stoves.

Water (moisture) freezes at 32f and is most likely the cause of your problem. I know that my propane dealer has an additive that he uses to absorb any moisture in the system.

I heat my house with propane and know that at around minus -28f below zero my propane takes longer to "Boil Off" and starts to cause my furnace to starve for fuel. The vapor (Boil Off) is not making it to the regulator as fast as the system is calling for it.

I should also point out that -44f is relative to sea level. But this is only important if you are doing testing that requires absolute know values or if you want to be a stickler for details.

quote:

but a new regulator with a built-in housing cured the problem

Ditto here for me too....I've also been advised by people-who-know to:

1. Keep the supply valve closed when not in-use.

2. As much as possible, keep tanks above 50% in cold weather to assist vaporization.

3. Propane supplier has the ability to inject methyl alcohol into the system for existing problems.

Bill, I went thru all of this also. Like to have never figured it out. A friend finally just told me to reset the lpg detector, and viola, it turned it back on. My Regency lpg alarm, when activated for some reason, turns the gas off. And then there is an electrical switch behind the lpg acess door controlling the on off of the lpg gas. Happy holidays. sky

towerguy & sky both run Cat Regencies, & both have similar problems. Both instances evidence the fact that the more bells & whistles you have, the more opportunity there is for some minor glitch to jump out & bite you at the worst possible time.

I still love my recently departed gas-powered, gussied-up potato chip truck that a shade-tree mechanic like me can maintain with a screwdriver, pliers, paper towels, duct tape, WD-40 & parts from my neighborhood NAPA store. (Maybe it's not really quite that simple but you get the picture.)

Not sure what the problem is but almost sounds like you have a tank of butane. Butanes boiling point is about 35F and that is above zero. If the temp goes above 35 and it starts to work it sounds even more like butane. Where did you fill it up. Lots of places in the south sell butane. Actually your gas match is butane. Leave it out where it is freezing and they will not light. Have to warm them up also.

quote:

Originally posted by sky:
Bill, I went thru all of this also. Like to have never figured it out. A friend finally just told me to reset the lpg detector, and viola, it turned it back on. My Regency lpg alarm, when activated for some reason, turns the gas off. sky

Hey All,

I'm hoping that Sky's answer is the one that works, especially since it is the easiest cure. When the tech was working on the coach, I had already reset the LPG detector. He said it was due to warmer temps but now I wonder if it was resetting the detector that actually cured it.

Anytime I'm not using the coach, I turn the coach battery master switch off. When turning it back on, it sets off the LPG Detector. Sometimes, I have to shut the detector off and turn it back on again in order for it to cycle correctly. Maybe this is where I'm running into trouble. I'm not sure if the detector needs to be replaced or if they would all respond in this manner.

Wwe have storms inbound so I'll certainly have a chance with the resulting colder temps to check this theory out.

Thanks for all the input!

Bill, if you are turning the coach batteries master of, it turns the lpg detector off and in turn, turns the lpg off for safety. That is exactly what happened to me when mine was disconnected to clean terminals. Reset the detector, and every was fine.
Happy holidays.. sky

Propane exists in rv tanks at a pressure of 140 psi (and any tank). The vapor pressure is realted to the temperature of the liquid and it is correct that at one atmosphere the boiling (or freezing point) is -43 C. when you add cold temperature of the tank and the environment to an internal pressure of ten atmospheres the boiling point is 32 deg F. An explanation is discussed at: http://en.wikipedia.org/wiki/Vapor_pressure. Some of Canadian friends and those who have been in Alaska may remember why heating oil is so prevalent - it is because LPG is sluggish at best in cold temperatures. This is not to say every time it reaches 32 deg F everything stops, but add cooling from cold air passing under the coach, a full tank under 140 psi pressure and perhaps water or other contaminants and propane will not be your friend.
If it is all corrected with a little heat on the tank this phenomenon will be proven.

quote:

Originally posted by Tom K:
Some of Canadian friends and those who have been in Alaska may remember why heating oil is so prevalent - it is because LPG is sluggish at best in cold temperatures. This is not to say every time it reaches 32 deg F everything stops, but add cooling from cold air passing under the coach, a full tank under 140 psi pressure and perhaps water or other contaminants and propane will not be your friend.
If it is all corrected with a little heat on the tank this phenomenon will be proven.

Yup. In NW Iowa, we depended on propane for our heat, fridge, cooking and lighting. During cold snaps, my dad would build a pen of hay bales around the propane tank and herd some of the livestock in to keep it flowing. First year, it was pigs, because you could get by with a lower wall. Well, pigs that can't eat 24 hours a day are unhappy and crabby, and their feeder lids would clank and keep us awake at night. They were soon replaced with cattle.

The grass was always greener there, and required much more mowing.

When the LPG supply is turned on and a gas valve opened to an appliance, the pressure in the tank decreases, and so does the boiling point.

That, however, isn't the reason why the furnace in StaRV II is happily warming the coach at 16F.

The reason is that, even as a liquid at 32F, the tank is under pressure (of around 110psi, IIRC). Opening a valve to the atmosphere (furnace burner, stove, etc.) at 14.7 psi causes the LPG in the tank to flow toward the lower pressure. Then the presure regulator reduces the pressure to ~.5 psi, and the LPG now gassifies.

Actually, most of the LPG is a liquid in the tank at all usual temps, regardless of the boiling point at one atmosphere, due to the pressure. If the temp rises, enough boils off the increase the pressure so the remainder remains liquified.

Getting a load of butane would be virtually impossible, as it's not handled, distributed, or shipped the same way as propane.

I like the title of this topic, it matches my problem. But it is not below 0 outside, it is 80F.

So, here is the situation:
- last October when the snowstorm knocked out power in the state, I turned on the generator to power my house and turned on the propane to run the fridge to keep the steaks in good shape. I forgot to turn off the valve on the tank when power was restored. Oops, I won't do that again.
- This spring, the RV control panel tells me propane tank is still 2/3s full like I expect.
- propane pressure at the stove is weak, and decreasing, and there is not enough gas to fire up.
- I figured it was the regulator. I replaced the regulator. When the regulator was off, I put a rubber hose to the output of the on/off valve, and I could hear the "boiling" noise of the propane in the tank. I did this for a few seconds.
- With the new regulator on, I went to the stove, and I got some gas flowing. I heard it easily. The burners "almost" sparked up, but the gas pressure decreased and went to nothing again.
- The fridge also will not startup.


I am thinking I should remove the new regulator and see if I can hear the "boiling" sound for a few minutes. I am wondering if the propane pickup tube or the on/off valve has some type of blockage.

I am also thinking that the easier thing to do would be to attach a propane appliance to the tap point just after the regulator and see if it runs.

I am also thinking that I could also use that tap point as an input and set up a portable propane tank to feed the Barth and the stove. If that works, then it is clear I have a problem with my on/off valve or the tank itself.

There are no detector interlocks that I am aware of.

And if that is the case, with a 25 year old tank, it is probably time to get it tested or replaced.

What do you think?
Matt

From the symptoms, it sounds like there's an obstruction somewhere in the line between the supply and the appliances.

Propane isn't pure; there are always heavier ends (pentane through heptane), and these can form varnish-like deposits. They usually end up at the orifice of the appliance. Try the furnace and the water heater; these have the largest and second-largest orifices.