My furnace will not stay lit

[Harrisden54]

I had a simialr issue with my 384BR. It would light and go out. I ended up pulling the burner suspecting a bug or cob web. The burner was full of water and corroded. Dometic is familiar with water getting into the burner area on the vertically mounted furnaces and replaced the corroded parts. Water was entering through the exhaust vent. I installed a dryer vent cover over the exhaust but removed it when the techs at the Goshen Rally caulked around the exhaust flange and it seems to have stopped the water entering.

[ChuckS]

Since the furnace actually fires off the Sail Switch ISNT what is causing your issue.. the furnace will not have ignition nor will the gas valve open if sail switch doesn’t make contact when blown closed to complete the circuit...

I’d suspect the flame sensor is not seeing the flame correctly due to dirt, mud daubers, or improperly positioned flame sensor/igniter.

The flame sensor is what tells the furnace control module “I see a flame” and tells gas solenoid valve to stay open...