Heating Propane Tanks - Montana Owners Club

Icehouse · 02-01-2008, 06:19 AM

I am still having issues with my portable propane tanks getting REALLY cold. When it is about 15 degrees ambient temp, the tank compartments are running near zero. In doing some research I ran across a few suggestions. I just need something to keep the pressure up in the tanks as the temps continue to drop. I would like your thoughts before I attempt some of these. (The attached link sent chills down my spine - but it might actually work) [http://www.stumpfballoons.com/install_heat_cable.htm]
Also, what are your thoughts about using a blanket styly battery warmer on the tanks? Would it get too hot?

timothy · 02-01-2008, 06:49 AM

Bernie, Scares me in a big way. I keep my Monty parked full time in the mountains of West Virginia where it is very cold in the winter. My neighbor has the same problem as you do. He takes a electric blanket and covers his tanks. That also scares me but it works. I don't no why but mine has never done this and I am just 40 yards from him. Good Luck.Please have Tammy keep posting about how you are all doing. It is very interesting to see just how much the Monty can take and you all also.

bsmeaton · 02-01-2008, 07:09 AM

I think I would wait till he gets it UL listed and approved by the NPGA

.

Other than the obvious risk resulting from a direct short in the heat cord that starts the wrap on fire expanding the fuel causing fuel venting that further aggravates the fire that propagates into the upper level and basement area that burns the trailer to the ground, all within 270 seconds........ there is probably low risk of a direct short having sufficient heat to penetrate the tank or cause a fire leading to BLEVE (Boiling Liquid Expanding Vapor Explosion)

. Therefore, it most likely would burn rather than blow up.

The battery blanket might serve better as it wouldn't get as hot.

If you try area heat, DO NOT enclose those spaces. The open floor is a huge safety system for on board LPG!

I think I would go directly to the propane industry and find out how they do it, or if they even see the problem.

ole dude · 02-01-2008, 07:22 AM

Brad- serious subject I know, how ever you crack me up,man. LOL

Icehouse · 02-01-2008, 07:24 AM

Brad, a simple "don't use the cord wrap" would have sufficed.

However, thank you for the thought process. I do NOT want to enclose the LP space for the obvious ventilation reasons. But it is this same area that is getting and retaining the extreme cold and is actually colder than the air temp. Thus my attempt to find some way to keep LP well above -20. This issue is just making the heater not as efficient and harder to keep us warm.

bsmeaton · 02-01-2008, 07:39 AM

Sorry - hahahahaha, must be a passionate subject

I only bring up the cabinets being enclosed because I have seen folks do that to gain additional storage. If the tank ever failed, it would come inside the coach.

**Rondo** · 02-01-2008, 07:52 AM

I agree with Brad on the idea of enclosing the compartment. It's open for the reason of venting! You can store things in there and not plug the holes for venting. I would also go and talk to the LP company you get your gas from and see if they might have some suggestions. It's their business and they may have had others that have had this problem and be able to tell you what they did to help in the situation. Here's just an idea that just might work (don't know for sure however)-- how about using some of that aluminium wrapped bubble wrap around the tanks especially just after you get them filled next time. Just an idea might help and might not, don't know! Keep us informed Tammy!!

Icehouse · 02-01-2008, 07:55 AM

I already have the tanks foil wrapped - now the tanks AND foil are icy cold.
Bernie

Mrs. CountryGuy · 02-01-2008, 08:17 AM

Tammy,

Your temps surely are lower than what we experienced when we winter camped in Gaylord, Michigan, many moons ago. We had a TT, nothing enlosing the bottom of the trailer, cold cold cold cold. TT not what we consider to be state of the art for 2008, as it was built in 1989. I think we probably were in residence during temps down to 10 or so??? Yea, above 0. It has been long enough that I have blocked that info from my gray matter, we could have been to 0 and I would not remember! SNICKER.

ANYWAYYYY, I do not recall ever having the trouble you are having. We did run on our 30 pound tanks for a few days, but switched to a 100 pounder pretty quick.

That said, the furnace always ran just fine. The microwave was another matter, when we would arrive in camp, it was so cold that it would not run until the rig was warmed up over 40 or so.

Do let us know how this progresses. Very interesting situation.

racerjoe · 02-01-2008, 09:02 AM

Have you talked to your propane supplier yet? I believe that they make an electric heating belt meant for that application. In the steel industry, we used electric belts for that and also to warm up ss gallon grase barrels so they would work.Your only draw back would be power,it would take a good size draw for those to work.

Icehouse · 02-01-2008, 09:05 AM

Racerjoe, Bernie isn't here, he's gone to exchange one of the LP tanks at the dealer for a new one. They think it isn't getting enough back pressure or something like that. We haven't gotten a larger tank yet because we are waiting to move to Canada and will get one there. We are familiar with heat tape and have our valve area of our galley tank heat taped because it wanted to keep freezing. No problems since then. He seems to be leaning toward the thermal blanket idea after talking to an LP guy earlier, but I'm not sure. So much drama right now! I'll make sure Bernie reads your post. I am sure he will want to pick your brain! Thanks for the input! Tammy

illapah · 02-01-2008, 10:15 AM

Just talked to my propane delivery neighbor. He said that the flow should be ok at zero. Many degrees below zero would be cause for alarm. He said that if there is any water at all in the tank, that could freeze and cause problems. I think he said that is why he puts some ethanol in new tanks. Also, he thought that the most likely problem could be with a frozen regulator. All this based on the little info I had to provide to him.

hazmic · 02-01-2008, 10:27 AM

Hope this works the second time. We crewed for a hot air balloon. We heated the propane tanks when it was cool or cold out. We used heat tapes like you use on water pipes and then wrapped them in sleeping blankets[cheap ones]. We never had any issues with that set up. The idea was to keep the liquid hot so it would increase the pressure in the tanks. You would heat the tanks in the same way as to keep the propane in a gaseous state. We need gas and not liquid. Balloons want liquid and not gas. When cold,propane turns into liquid and will not work in our systems. Also there would be a pressure loss. How much pressure do you think there is when the tank sets in the compartment with the sun beating down on it or if setting outside. When ballooning we treated out tanks rougher then we do with the campers. Believe me on that. All you would need is the same tapes that we use on water pipes. Stiles, here we go again what a heating tape is.I dought that there would ever be a short in the tape or a issue with pressure. Keep us informed on what you do.

bsmeaton · 02-01-2008, 10:55 AM

Hazmic,

There is a huge difference between the sun shining down on your tank versus a tank wrapped in a burning nylon sleeping bag that caught fire from a faulty heat tape. Unfortunately, heat tape fails all of the time and is listed as a huge contributor to annual property loss values by NFPA.

Also, you weren't getting the liquid hot, because the liquid cannot get hot or it is no longer liquid. By heating the tank you are converting more of the liquid into gas which pressurizes the tank. The colder it gets, the more gas converts back to liquid and the pressure drops. However, liquid fuel tanks draw from the bottom, and gaseous fuel tanks draw from the top. Our montys could never get liquid unless you you laid the tank on the side or upside down, and then the safety ball would slam the valve shut.

Mudchief · 02-01-2008, 01:27 PM

Icehouse, I have not had a problem with the propane in the tanks but have with the valve and regulator freezing. What i do is put a 40 watt bulb near them and that is just enough heat to keep them from freezing if any moisture is in the tank.

bsmeaton · 02-01-2008, 01:31 PM

That sounds like a perfect fix Dennis. Anything radiating heat on the tank, valve and regulator would work. Because there is no combustible wrapping, there is no fire hazard that way.

Icehouse · 02-01-2008, 01:33 PM

Would love to use the lightbulbs. But with our added landing gear there is enormous ventilation in our LP compartments. Tried the lightbulbs. It raised by compartment temp to 2 degrees.

MacDR50 · 02-02-2008, 08:35 AM

If I offend with this long reply please forgive me. I think it is important to understand why propane is a poor choice for energy in really cold climates.

First, did you try the hair dryer on the regulator? If it frees with the heat then you have water or oil freezing up in the regulator.

Now for the long winded reply. Propane will boil off at -44F at 1 atmosphere. As pressure in the tank rises it raises the boiling point just as a pressure cooker does to water. When you open the tank to system demand this drops the pressure and the boiling point. Any restriction in the system, say in a regulator will keep the pressure up and you get less boil and consequently less propane gas. The propane boils using heat energy from its surroundings. This cause a cooling effect that can be seen as frost on the tank sides. You will note that the frost is on the lower portion of the tank where the propane is still a liquid. Once the gas enters the piping system it continues to expand in volume as it absorbs ambient heat. When it enters a mixing device such as the venturi pipe on a stove burner it mixes in the proper ratio with air and then "hopefully" is ignited. At really low temperature the amount of propane boiling off may be insufficient to supply system demand. Low, weak flames are the usual indication. Sputtering, yellow flames are a good indicator of propane that is contaminated with water.

We use propane where I work for forklifts, heating mobile command shelters, steam immersion heaters and for helio-torches which are used to ignite oils spills on water. None of the propane tanks have any form of tank heaters. I will check with my certified gas fitter on Monday if he has ever heard of such a a thing.

One last thing. I checked my own copy of the serviceman's handbook and it states that only METHANOL and no other alcohol should be used as an antifreeze in propane tanks. It doesn't say why. Here is a link to the handbook site. http://www.fisherregulators.com/lp/pdf/handbk.pdf

Icehouse · 02-02-2008, 08:44 AM

Hi MacDR50. Bernie is currently doing surgery on the black tank and I'm entertaining myself with the forum. Yep, we used the hairdryer. Ended up taking the tank to our dealer and getting a new one yesterday. Worked like a charm all night long. We were toasty warm. Since the unit is only 5 weeks old, they didn't give us any flack about exchanging a tank. Bernie will post on his thread later tonight (after he stops playing Dr.) and can talk to you more intelligently about this than I. Absolutely no offense taken from your post. Thanks for the help!

Exnavydiver · 02-02-2008, 10:59 AM

As gas is leaving the cylinder it is also drawing off heat. I have seen a frost line on my gas doors at the propane level on cold rainy days. It was frost and ice. Just as in filling a scuba bottle produces heat, rapidly off gassing causes cooling. The colder it is the more the furnace runs. The more the furnace runs the more gas leaves the bottle. Heating the compartment or bottle makes sense. Even if the outside temp is above freezing, the draining of fuel to the furnace will cool the bottle further. I don't like heat tape either, my plan would be to hang a hundred watt bulb under the bottles..

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