Norcold 821L

[wolverine68]

I have a little bit of a head scratcher issue with the fridge in my 2007 Desert Fox. While out on the May Long weekend, the fridge (2way) ran on propane for the first two days. On the third day, I noticed that it was showing an "F" (fault). I restarted the fridge and it wouldn't ignite. I could hear the gas valve open, the the igniter cycle through, but no fire. I checked the propane by lighting the stove and batteries were at full charge. I switched to the genny for a few minutes and then went back to trouble shooting. After switching back to gas operation, it fired right up as normal. A couple of other times on the trip I found it in "F" mode, switched to AC and back and it would fire right up. As of now, it has been running for 24hrs on gas with no problems. I hate intermittent issues like this. Thoughts?

[wolverine68]

Thanks for the feedback. I was leaning toward the mother board as well. I originally ruled out propane supply as the stovetop lit right up but when I checked the propane bottles, I noticed that the auto-switching propane regulator was on an empty bottle. I now suspect that when the bottle ran out, it would supply a large flow(stovetop) but not the fridge.I switched the supply to the full bottle and have not been able to get it to act up since. Perhaps the autoswitch was not operating properly after the long winter of not being used????

[DFord]

Old Biscuit is on target.

The igniter on the refrigerator is also a sensor. If flame isn't proven right after it sparks, it will wait a few seconds and try again a couple of times before a safety lockout. To get it to try again, you need to turn the refrigerator off and back on.

There's a unique thing about flames. They only allow DC current to pass. The control board sends an ac signal to the combination flame rod and igniter. It expects to sense a dc current when the flame is present. If it senses an ac current, it knows the flame rod is somehow shorted. Rust may have fallen on it allowing it to pass the ac signal and stopping the ignition process.

If you get up on the roof and remove the refrigerator vent cap, you can pull the spiral out of the flue and brush it off. Raise it up and down to knock all the flaky rust off the walls of the flue. Running a bottle brush (flue brush) up and down helps too. Vacuum out the burner area to remove all the fallen rust before trying it again.

If all that fails, it might be time to think about a control board.

[Old-Biscuit]

Dirty burner tube.....rust flakes on slots etc

Bad circuit board