A genuine Propane Puzzler

[Grouchyoldman]

I offer the following story of a weird problem my wife and I experienced on our first cold weather trip. I now know the answer and I wonder if anyone here can nail it?

We recently purchased a 2016 Coachmen Freelander 21QB in Virgina and we've been packing in as many trips as possible before the really cold New England weather shuts us down. We were caught a little by surprise when that November Polar Vortex swept down on us while we were visiting Gettysburg, VA. The nights got down to 12 degrees and our Little House was damned uncomfortable when we woke up at 2:00 am to find that the furnace had stopped working. I started preparing to go outside and do battle, but the Saintly Spouse calmed me down. Instead we threw on an extra blanket and snuggled close to get through the night.

In the morning I tried the stove to perk a pot of java and it worked fine. When I turned on the furnace it also came back to life as if nothing was wrong. Perplexed and ever the optimists, we tried to believe it was just a quirk. That still seemed plausible the next evening when the furnace obliged and kept the place cozy all evening. Early the next morning however we woke to a cold house again.

I plowed through a few hundred forum posts and youtube vids and came to the conclusion that the regulator was probably bad. Annoying in an almost new RV, but it's pretty well known that Forest River doesn't always use the highest quality components. I think the term of art is "Value Engineered." In any event I was lucky to find a nearby RV shop that had the correct replacement regulator and was willing to install it while we waited. We tested the fix by lighting up every propane appliance we had: genset, furnace, hot water, refer, even the stove and oven. Couldn't make it fail, must be all fixt. Cool beans.

No deal. Next night, on the road back to Cape Cod it got *really* cold and the furnace wouldn't even light up in the evening. Stranger yet, the stove worked fine, even the oven. The water heater lit up normally and I could hear the furnace trying to light, even getting flame but then going out. Then things got worse as even the stove top burners got really low. Finally, there was only enough gas to keep one burner barely burning.

Sheesh! New regulator, full propane tank, what the hell? I had read that propane could freeze up if there was a large volume running through the pigtail behind the regulator, so I pulled out the little electric space heater and when I held it up to the propane pigtail hose my wife reported that the stove flame immediately leapt back to normal size. We tried the furnace and voila! Too strange.

Our trip ended and I took the RV to our friendly dealer, Majors RV up in Bourne, MA. Their "propane guy" David was out at the time but he called me back later that day and after patiently listening to the details, he nailed it in one shot.

I realize that this is a long winded story, but there are probably some expert propane folks on this forum and I thought I'd challenge you to diagnose this problem. I'm not going to provide any hints beyond the details above, but I'll check back here in a few days and see if anyone can solve this puzzler.

Cheers,

-Grouchy

[Jay2504]

My guess is moisture in the propane line freezing up and partially plugging off the supply. The cure was to raise the line so the moisture drains away from the place where the problem occurs. Jay

[dustman_stx]

Not a propane expert by any means, but I'll take a shot at it: Propane tanks weren't purged properly and there was air/moisture in them that was freezing up at the regulator? This may be way off base, but I do recall doing some research that indicated you could have "issues" if they aren't purged properly the first fill.

[Grouchyoldman]

Jay & the Dustman: You guys are good, but that's not the answer. Let's let this simmer for awhile and see if anyone else gets it.

Thanks,

-Grouchy

[AFDON]

Your propane was filled in VA in the summer. It was the wrong mixture for COLD weather. Propane has some other gasses mixed with it for cold weather to keep it vaporizing properly.

[gasman6674]

An improperly purged tank would cause freezing/frosting of the regulator whenever there was a draw on the tank. It starts frosting from point of restriction downstream in direction of flow. So if a regulator starts to freeze at the inlet generally the whole body will frost.
I suspect you may have got a heavy dose of butane. Butane boils a 32Deg so anything less than that pressure will fall off and eventually fall to zero.

[jeff64]

A WAG, your consumption exceeds the vaporization rate of the lp at that low of temperature. Are you running on 1 tank or 2 at the same time? and did he tell you to run off both and keep them full? Too bad the tank heater concept doesnt extend to lp tank warmer.

[Iwannacamp]

watching

[5picker]

Originally Posted by AFDON

Your propane was filled in VA in the summer. It was the wrong mixture for COLD weather. Propane has some other gasses mixed with it for cold weather to keep it vaporizing properly.

Originally Posted by gasman6674

An improperly purged tank would cause freezing/frosting of the regulator whenever there was a draw on the tank. It starts frosting from point of restriction downstream in direction of flow. So if a regulator starts to freeze at the inlet generally the whole body will frost.
I suspect you may have got a heavy dose of butane. Butane boils a 32Deg so anything less than that pressure will fall off and eventually fall to zero.

I'm going to agree with these two.

The propane tanks were filled in VA.
The propane was blended for warmer weather.
It couldn't boil and produce gas at the temps you were experiencing and is why the electric heater near the supply helped.

My 2¢...

[Grouchyoldman]

WE HAVE A WINNER!

Actually, two winners, The grand prize goes to our LPG gurus AFDON who first caught a sniff of butane, followed up admirably by Mr. gasman6674 who nails down the Butane/Propane mixture as the culprit.

As it turned out, the original owner had taken his one and only vacation in the RV down to Florida and while there he filled my gas tank with Butane. Apparently this is a frequent practice down South where it doesn't freeze in winter. Butane is significantly cheaper than Propane, and even though it doesn't have the equivalent BTU output as Propane, it's "Good enuf" for most folks.

When we bought the Class-C Freelander, it had almost a full tank so when we topped it off it only took a couple of pounds of Propane. If you think about it, the mix of Propane and Butane was the key to the puzzle because it created an intermittent failure that only showed up when it got below freezing and also after all the propane already "gasified" had been consumed by the appliances. The regulator of course had nothing to do with anything so now I have a spare reggy.

The solution in the end raised another interesting topic, purging the tank of butane. There's a Big Red thingy on the bottom of my (built-in) propane tank labelled "Purge," but I have been cautioned never to touch it.

I was advised to just turn on the furnace and let it run until the tank was empty.... it took three and a half days! When it was completely empty I put a couple of pounds of nice fresh Propane in the tank and all is well. The last time it froze here I sat out in the RV with the furnace blazing and watched the NE Patriots dominate the field in total comfort.

So, thanks for playing everyone! All hail AFDON and the GasMan as the golden gawds of LPG wisdom.

Cheers,

-Grouchy
PS: Runner-Up: 5picker!

[carlsbad]

Smaller tanks lack the volume to vaporize properly at extreme cold temps.

[tuckerdog1]

I learned something today. Thanks,

Tuckerdog1

[alsdas88]

Love this forum for all this good information. I have never heard of Butane being available in quantities to fill an RV tank. Now I know what to be aware of for the future.

[Iwannacamp]

Glad you figured it out.... I feel I was at a disadvantage because I didn't know the answer. Gasman cheated.



JK... glad we have experts

[ben31]

Yep, learned a major lesson today. I go to Fl quite a bit and then come back a little north. I normally fill the tanks down there, so will need to watch to make sure I don't run into this problem.

Again, thanks!!

[mzbrandi]

Interesting. Out west, I've never seen a place to buy butane. Yes I can see how you had problems as butane "boils" at +32* and propane at -40* (+\- can't remember exact temp). Good job figuring out the problem.

Brandi

[SecretSquirrel]

Yep, learnt something new today. Thanks!

[Cypressloser]

Dang, I found your post to late.
I knew exactly what happened as soon as I started reading, but then I have a slight geographic advantage
Never pack a butane lighter in your winter emergency kit, good old matches and wax candles only.

[Jay2504]

I too learned something today. I didn’t even know you could fill rv tanks with anything other than propane. Jay

[MCCOY1998CARDINAL]

Sorry you had a chill down a couple nights and blankets do work wonders.
It's always something and the hassle/time involved can get frustrating...great we can all smile that you found the answer and the game was fun as I learned by reading the varied answers.
Now I'll get back to my Suburban SF-35 furnace, rebuild. Each time the Motors fail...ANNUALLY, I get to re build. The parts are now trickling in as I'm replacing any/all components that look weak. 1998 Cardinal and she needs love and care at times....
Gettin' a little chilly in Iowa these days and I'm hoping to have buttoned up by this weekend. All Good as long as I can beat the deep freeze next week....?
Last part coming Thursday....always something. At least she's paid for and no more Big Mortgage after selling big house. The Farm is the current paydown project I live for...every spare greenback goes that direction.
Great excercise , Mr. Grumpy. I can relate to your LogIn , when working on these furnaces....