Dometic 3-way won't light on propane

[the_Jabbster]

The Dometic RM2553 3-way fridge in my cabover camper suddenly stopped working in propane mode recently. It still works perfectly in 120 VAC mode, all other gas appliances still work perfectly (stove, water heater, furnace.)
The batteries are charged, I've taken the burner out, filed the rust off with a fine file & cleaned it out with compressed air & alcohol. I can't get the thing to light, it doesn't appear that gas it getting to the burner. I'm not sure how to check the gas pressure...is that the next step? Manual says I should see 11" wc at the test port, is the pressure regulator something I can adjust, if so where is it & how do I adjust? Could this be a board issue? I appreciate any help!

Thanks,

James

[the_Jabbster]

Thanks everybody for the tips. It did turn out to be the thermocouple. $40 and a trip to Camping World fixed the problem.

[gkainz]

When the flame does burn, is it a nice blue flame or a lot of yellow tips? Clean or sorry sooty burning? (edit to undo autocorrect)
Is the thermocouple positioned in the flame per manual? I don't recall exactly but something like 3/8" above the flame?
Thermocouple can be metered for resistance ... Specs are out there somewhere and google should find it.
My next guess would be thermocouple or controller board.
Dinosaur board is a good source for replacement controller boards.

[the_Jabbster]

Already have manual, Thanks!

does the igniter even try to spark?
It does, I can get it to stay lit if I press and hold the Push-button igniter on the front panel.

can you light it manually? I know you said "seems like gas isn't getting to there" but have you verified that? How?
I was wrong, gas is there. Does this sound like a thermocouple?

If no gas (suddenly, after working ok) then maybe gas shutoff solenoid?
Controller board?

Need to step through troubleshooting steps, and verify
12V
Gas
igniter
thermocouple

checking gas pressure would not be next in my steps - I would verify presence of gas in ANY pressure is getting to the burner.

If yes, then MAYBE check pressure but a number of things still to check

The fridge needs:
12V to open the gas solenoid
12V to ignitor to spark
gas to burner (orifice not plugged - spiders love to build webs there)
thermocouple to sense flame
controller board holds open the gas solenoid once flame is sensed

controller board also does a bunch of the sequencing of the above.

[gkainz]

some tips on things to check here

manual

does the ignitor even try to spark?

can you light it manually? I know you said "seems like gas isn't getting to there" but have you verified that? How?

If no gas (suddenly, after working ok) then maybe gas shutoff solenoid?
Controller board?

Need to step through troubleshooting steps, and verify
12V
Gas
igniter
thermocouple

checking gas pressure would not be next in my steps - I would verify presence of gas in ANY pressure is getting to the burner.

If yes, then MAYBE check pressure but a number of things still to check

The fridge needs:
12V to open the gas solenoid
12V to ignitor to spark
gas to burner (orifice not plugged - spiders love to build webs there)
thermocouple to sense flame
controller board holds open the gas solenoid once flame is sensed

controller board also does a bunch of the sequencing of the above.