Dometic Refrigerator Not Working on Propane

[vagaron]

Last time the fridge was used was 6-8 months ago and ran on AC or LP. Switching it on today in preparation for a short trip this weekend, the "Gas" light on the panel stayed on for a bit, then the "Check" light came on. I tried powering the unit off and back on several times as the manual suggests with the same result.

After the second attempt I checked the fuses in the back. All were OK except one 1A in-line fuse on one of the wires outside the control box which I replaced.

When I first power it on, I can smell some propane from the lower vent panel outside the coach, but can't hear any ignition.

Only thing I found was a blue wire (see photo) coming from a plug in the upper left of the control box that wasn't attached to anything. I couldn't find a likely place for it.

Is there a fuse inside the coach for the ignition circuit?

Looking for clues...

[Waiter21]

1st - Whenever I turn on the propane and power up the furnace or frig after being off for more than a few days, I always light one of the stove burners first to verify I have gas in the lines.

I had this same problem when we bought our Soutwind in March. A month ago I was finally able to work on it and went through a good troubleshooting process . I ultimately replaced the controller with a dinosaur controller board. This resolved my problem.

On my RM-3862, the blue wire isn't connected to anything. I went through an exhaustive cleaning and troubleshooting process that I wrote about ion my blog.

Dometic frig works on AC but not on propane – 1999 Southwind 35S

NOTE - My solenoid valve has a manual valve built into it, make sure its turned ON.

On mine, I suspect the problem was with the thermocouple, what they call a "ground bounce" problem (The thermocouple is picking up noise from the ground connection) When it does this, the OEM controller board thinks this is a defective thermocouple and won't turn on the gas and igniter

The Dinosaur board solves this by moving the thermocouple off of the ground reference.


Your controller board is different than mine, but they should work similar. If you decide to replace the controller, verify your model with the Dinosaur people to make sure you get the correct board.

IGNITION CIRCUIT

On mine, the ignitor module is located just to the right of the control board ( you'll see the black cover in some of the photos on my site).

My ignitor and gas valve are powered on with one wire. When power is applied, if there isn't a flame, the ignitor will spark to the burner tube, maybe once a second. The ignitor wire needs to be clean and about 3/16 inch from the gas tube.

When the gas lights and creates a flame, this changes the resistance of the spark gap and the ignitor cant spark as long as there is a flame. If the flame blows out, the air gap resistance changes and the ignitor will start sparking again.

[vagaron]

My problem just -- disappeared. Not only was the fridge not working on propane, but I later noticed the cooktop wasn't igniting either. As the fridge manual suggested, I shut it off and back on several times. No luck.

After hooking up to shore power at an RV park, it successfully ran on AC for one night. When I disconnected the electric before leaving, it automatically switched to LP and stayed that way.

Also, I lit the cooktop with a match. After that burner was on for a few minutes, the other started working with the automatic ignition and then both were working ok.

I know when you haven't used an LP appliance for a long time it can take a while for the gas to re-prime, but in this case the gas was there. The ignition wasn't happening. Or maybe there is some LP detect circuit that takes a while to realize the gas is on again??

I dunno. Just happy things are working.