Atwood Furnace issue-need suggestions Please.

[dad4papa2]

1996 Damon Intruder has an 8535-lll Atwood Furnace in it. It has always worked perfect but went out the other day and turned it on.

Furnace fired right up as always and fan run for a bit and then ignited. Then after running for about 3-4 minutes it went out. Fan continued to run and after a few seconds ingnited again. Now it runs for about 30 seconds and shut back down.

So where do I start? I have read about the sail switch. Will it do this??

Limit Switch??

Where do I start??

Thanks in advance. Dad

[dad4papa2]

Thanks guys i will look at both suggestions. Hope to get it going!!
Dead

[3_tons]

There is a two prong ignition prover in the exhaust port...Try removing it and re-gap it to about 1/4” gap...

[enblethen]

Locate the circuit board, disconnect and clean multi-wire connector.
Possible flame sensor is not in flame or bad circuit board.
Compare circuit board in water heater with furnace. If same swap them to see if it works.