Caution: Propane gauges blamed for furnace ignition failure - Montana Owners Club

DCB · 12-18-2018, 11:29 AM

I have been having intermittent problems with the furnace recently, and thought I would share my experience and the solution (fingers crossed).

The Problem
Intermittently, the furnace would fail to ignite. The problem seemed to occur on the coldest nights, in the wee hours. We would wake to temps in the low 60's in the coach. I could sometimes nurse things along by turning off the thermostat, waiting a few seconds, then turning it back on. However, that proved to be only a temporary solution. While the furnace might run for a few more cycles, it would ultimately fail to the point where nothing I could do would get it going again, and we would just have to endure the early morning cold with the fireplace as the only source of heat until daytime temps warmed to the point where the heat pump could be used.

With benefit of daylight, and some hints from this site and others, I removed the outside furnace panel to see what I could find. The red light blinking pattern indicated an air flow/limit fault. (I could not find a clear, authoritative explanation for the potential causes triggering that error and possible solutions.) Sometimes, when ignition failed, I could turn the furnace switch off, then back on, and it might ignite for a few cycles. I think that was basically accomplishing the same thing as turning off the thermostat inside, then turning it back on. Either method would only work temporarily, then nothing I could do would get the furnace to light.

Based on information on this site and maybe elsewhere, I wondered whether our use of magnetic covers for some of the heat registers was contributing to the problem. We stopped using them, but the intermittent ignition behavior persisted. (To conclude this particular rabbit trail of thought, the service manager later told me using a cover or other method to restrict output from a register had nothing to do with the problem, and it is perfectly alright to use them.)

Nothing else obvious stood out. There was plenty of propane on board. Switching tanks accomplished nothing. Stove burners operated fine. When we took it in for service, the mechanic could not get it to fail (of course). We took it back to our site, and on the next cold night it failed (of course).

The Solution
Back to the servicing dealership for a second visit. This time, the service manager (who was out for a doctor's appointment on the previous visit) noted we had gauges on the tanks similar to the one pictured. (Note: The image is from a Lowe's product, but ours were not purchased there. Just using it as a representative example.) His experience over many years with such gauges is that they cause more harm than good by eventually restricting the flow of propane. He removed the gauges. Since then, the furnace has been working fine. It hasn't yet been 24 hours, so if something changes, I'll update this post. But we made it through a cold night last without any issues -- and used the magnetic register covers.

I'm posting this because others may want to be aware of the potential issues with these propane gauges. We're just getting started with our RV adventure, and we made it through a few weeks before the problem described above began. Looks like we'll toss the gauges and use more rudimentary methods to determine the levels of propane in our tanks.

waynemoore · 12-18-2018, 12:00 PM

I learn something new every day. Thank you.

BuilderBob · 12-18-2018, 12:07 PM

I had a buddy that had those and had all kinds of problems till he took them off!

jcurtis934 · 12-18-2018, 12:13 PM

I bought the trump hand held unit to keep tabs on the propane level in the tanks. Great device.

bshgto · 12-18-2018, 03:08 PM

https://www.amazon.com/AP-Products-1...evel+indicator

I bought these units seems to work very well and has saved my butt more than once. Just a little finicky after you put the sensors on the bottom of the tank you have to let the gaseous liquid settle after moving the tank before you try the inside gauge, I mean like 5 mins before it finally stops sloshing around. The other possible problem, some tanks (in the minority) do not have a small flat area on the bottom in the center of the tank to mount it the outside sensor on.

They work for me no more guessing.

Texan · 12-19-2018, 12:32 AM

I have the same gauges and have had no problem with furnace but found these not to be very accurate so removed them. I have automatic change over so when one gets empty and changes over I have the empty one refilled within a couple of days. It helps that I have 40# bottles so I don't have to fill as often as the 30# bottles. Thanks for sharing the problem.

Kyle and Lisa · 12-19-2018, 07:45 AM

We have used the same type of gage on a 5 gal. tank, not very accurate.

richfaa · 12-19-2018, 08:36 AM

We use the guage that came with the RV 12 years not a problem.

WeBeFulltime · 12-19-2018, 02:30 PM

We are having the same problem with our furnace with the same exact symptoms. Dealer checked it and couldn't get it to fail and I have replaced the pigtails and regulator/auto changeover which made no difference. We do not use any type of gauge for propane as we just fill empty tank as soon as the switch over has occurred. I have also tried a new Dinosaur brand board in it. It's driving me nuts!

**AZ Traveler** · 12-19-2018, 03:25 PM

Quote:

Originally Posted by WeBeFulltime

We are having the same problem with our furnace with the same exact symptoms. Dealer checked it and couldn't get it to fail and I have replaced the pigtails and regulator/auto changeover which made no difference. We do not use any type of gauge for propane as we just fill empty tank as soon as the switch over has occurred. I have also tried a new Dinosaur brand board in it. It's driving me nuts!

Have you tried turning both tanks off and then opening the valves very slowly? Also set the thermostat up high - the temp error on the stat can be as high as 5-8 degrees.

WeBeFulltime · 12-21-2018, 07:16 AM

Quote:

Originally Posted by AZ Traveler

Have you tried turning both tanks off and then opening the valves very slowly? Also set the thermostat up high - the temp error on the stat can be as high as 5-8 degrees.

Thanks, but have tried those.

Kyle and Lisa · 12-21-2018, 07:47 AM

Our furnace started acting up yesterday , after inspection I found a dirt dobber nest in the exhaust pipe, still ran intermittently, cleaned carbon build up off of igniter, all is well runs normal.

Fish · 12-21-2018, 03:52 PM

I had to have a mobile tech fix my furnace. He said the sail switch wasn't catching enough air and was also sticking to the side of the housing. He bent it a little and it's worked every since ($200 later). He also said if that didn't fix it for good the next call was on him.
He said the furnace was a new design which he really liked except for the way the sail switch sat.

vipermanden · 12-23-2018, 01:36 PM

I have never run out of propane and have never used a gauge. I just keep one tank closed, and if i run out of propane in one, which I did once, I would then turn on the other tank, and get the first tank filled again. So my backup was always having a full tank by not keeping both tanks open and then being surprised that they were both empty.

Fish · 12-23-2018, 02:50 PM

Quote:

Originally Posted by vipermanden

I have never run out of propane and have never used a gauge. I just keep one tank closed, and if i run out of propane in one, which I did once, I would then turn on the other tank, and get the first tank filled again. So my backup was always having a full tank by not keeping both tanks open and then being surprised that they were both empty.

That's what I do. Plus I have 2 extra 30 pounders. All 4 30 pounders are on the ground under the fifth wheel. I bought pigtails to connect the 2 tanks so I don't have to lift them in and out since I'm living in it pretty much full time while at the refinery and using a lot of propane in the winter.

I bought the hose extensions when I still had the Rockwood Windjammer and was at the refinery last year, since changing the propane tanks on that trailer was a major pain. The extensions have gauges on them which I pretty much pay no attention to. I lift the tanks to check their weight and look at the switchover valve to see if one is empty, then I change it.

agggitator · 12-23-2018, 05:07 PM

I've been having the same issues for a year now. I don't have gauges on my tanks, I've had everything but the furnace replaced, still no luck. It's back in the shop for the 5th time, hope they figure it out this time. I love my Monty, but damn is getting frustrating.

Mikendebbie · 12-23-2018, 05:45 PM

I had the same experience on my Laredo (before Montana).
By the way I have barely used propane gauge for sale cheap.

jcurryii · 12-23-2018, 09:57 PM

Tank Check works great.

JamesD · 12-23-2018, 10:03 PM

My furnace had issues a couple years ago, but it turned out that the large propane tank I rented had an excessive amount of ethyl mercaptan (the stuff than makes it stink) and it filled the propane lines on my RV. I had to disconnect everything and drain it, then take apart the furnace to clean the nozel leading into the burner. I cleaned out a couple wasp nests while I was at it. The stove still gives me some problems.

margerush · 12-24-2018, 05:29 AM

bshgto: we have the propane monitor (Tank Check LP with Monitor Kit) on our tanks--they didn't work for us. LP tanks were empty but the monitor said they were full. The bottom of our LP tanks are rounded where we stuck the "guage". Since the bottom of the tanks are rounded, is this why the monitor didn't work?

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