Dometic 3way only lights on 5

[Tomd3]

My Dometic 3 way frig only lights and will only stay lit on 5 (coldest). Any other setting and it will not light. If I light it on 5 and then adjust to 1,2,3, or 4 the pilot goes out. Works fine on 110v. any advice appreciated.

 

[Gpa]

any chance bugs/spiders have nested in the gas lines?

 

[Alloy]

First thought was the thermistor inside the fridge but it couldn't be that if it works on 110V.

Second thought was propane or but it stays lit on 5.

Third is the display / control board

If you are lighting the fridge....how old is it?

 

[Nailhead]

If it's like mine, it has a bypass screw in the thermostatic valve that allows the flame to stay lit after the interior of the fridge reaches set temperature and the thermostat cuts the flow of gas to the burner. These screws, according to the service literature I've read, can get dirty and allow the burner to go out when the set temp is reached.

This applies to an RM190 made in the Reagan years, so it might not be relevant to your situation.

 

[Tomd3]

Thanks for the replies. The thermocouple idea hadn’t occurred to me because it would light, but it makes sense that it could be the problem. I’ll check it out.

 

[Tomd3]

After running on LP for a few days it lights and runs on any setting. Go figure.

 

[Stan@FourWheel]

There are a few things that it could be, but I would clean the burner tube first off.

Clean the slits where the propane comes out and the flame is burning.

Soot and rust builds up on that part over the years, and it really needs to be clean and free of rust so the flame can burn tall & healthy.