Hello all, I’m at the end of my tether and need some advice. I have a 2019 High Country fifth wheel 330RL. Last week while we were dry camping in North Carolina on our way to Florida, the furnace (not sure of model number) started malfunctioning. It would start up, ignite, and run normally for anywhere from 1 to 5 minutes. Then it would cut off and try to start back up again several times for about 10 seconds. While it was doing this, the whole control pad would blink in and out as if there was a bad electrical connection. After about 10 seconds, the thermal cut off fuse/breaker in the electrical panel will trip. I removed the breaker to check it and it was very hot. After about 30 seconds, the breaker resets and I can turn the furnace back on only to have the same thing happen. This doesn’t seem to be effecting the air conditioner, which runs off the same control pad. Has anyone else had this problem and already figured out how to repair it? Any advice would be greatly appreciated. Thanks, Dave McCoy.
You said you were dry camping.
Were you using a generator?
How does it behave running on shore power?
How does it run on battery only? (no shore or generator power).
We were boondocking and our 12vdc systems were intermittent. The 120vac systems running off the inverter were fine. Inverter is connected directly to the battery on its own 250vdc circuit breaker.
I knew it had to be one of the red 50A self resetting circuit breakers in the battery compartment going bad. I took a screw driver handle and smacked both of them. The 12vdc systems came back on.
Since then I replaced the malfunctioning red 50A circuit breaker. It would trip when pulling more than 12A.
Also try replacing the furnace black 15A self resetting fuse with a regular blue 15A (spare) fuse.
The propane furnace runs on 12 volts. Power passes through an automotive style fuse that does not reset, rather the fuse element melts away and a new fuse must be installed to restore power. A circuit breaker protects 120 volt circuits. Once tripped, it must be manually reset. The only 120 volt heating device sometimes installed on a camper is a heat pump which is part of the rooftop A/C. If you have a heat pump, the camper must be hooked up to shore poser to operate. The problem you have described, does not seem related to a circuit breaker issue. None of the circuit breakers should be hot if you are dry camping and not using a generator. The furnace control board has a feature that locks out the furnace from operating if a failure to ignite occurs 3 times. The 12 volt power to the furnace board must be disconnected to reset the furnace operation. Easiest way do perform the reset is remove the low voltage fuse and replace.
Actually, there are probably at least two 12 volt DC auto-reset circuit breakers on most of these Montana rigs. You will have one that feeds the hydraulic pump motor along with the line to the power panel inside, and there will be another breaker near the first one that feeds a number of minor loads. On the rigs that have a residential fridge, there will be another breaker that runs 12 volts to the inverter. These are the breakers you will find on these rigs that supply 12 volts.
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Bob & Becky
2012 3402RL
2012 Chevy 2500HD D/A CC 4WD
You are correct, but I don’t believe that his furnace issue is related to the auto reset fuse pictured. The furnace power comes from his 12 volt fuse panel. The op needs to provide more information for the forum to help.
You are correct, but I don’t believe that his furnace issue is related to the auto reset fuse pictured. The furnace power comes from his 12 volt fuse panel. The op needs to provide more information for the forum to help.
And the power from the 12V fuse panel gets there through the 50 amp self resetting breakers (that Bob showed) from the battery. If it is weak, it doesn't take to much of an amp draw to have it open up.
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Carl (n Susan) There is more to life than fuel mileage.
2012 Montana 3700RL Big Sky Package towed by a 2015 Ford F350 6.7L PSD 4WD CC LWB
Thank you for trying to help, I’m going to try to clarify this better. This is a Dometic furnace that runs on 12v and propane. This problem seems to occur whether I’m connected to shore power, or not. I don’t have a generator (yet). It appears to be isolated to the furnace operation only. The AC that uses the same touch control pad does not seem to be effected. The 15 amp thermal fuse that trips and self resets is located in the 12 volt fuse bank. It’s very hot when I check it after it trips. When I first start the furnace, the furnace fan comes on normally and the furnace ignites. It runs normally for a couple minutes, but then the fan cuts off and tries to start again repeatedly, so you get a repeated whirring sound from the furnace fan trying to run. This happens for about 10 seconds and during that time, the LED back light on the Dometic control panel blinks on and off at the same pace as the furnace fan trying to keep running. After about 10 seconds, the furnace fan stops and that thermal 12v fuse trips in the 12v fuse bank. About 30 seconds later, the fuse resets itself but is very hot to the touch. I’ve included a pic of the control pad and the fuse bank. The first black 15 amp fuse is the one that finally trips after the furnace’s seemingly dramatic attempt to cling to life. I hope this explains things better. Thanks again for all your help.
Swap that black 15A self resetting fuse with a regular blue 15A fuse. You should have a couple of spares in the end of the row.
If it blows the fuse, try cleaning and reseating all the connections in your furnace panel (outside). While you have the panel open see if the blower spins freely. The blower draws the most current. If it is impeded, it could cause the fuse to blow.
Ther is a furnace troubleshooting file in the files section at the top of this webpage.
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