Anybody have an idea on what might be the issue with the furnace in our 97, U295? The furnace is an Atwood Mod 8535 III. Last time we were out, I turned on the furnace but just got cold air blowing. Today I tried to blow out the combustion chamber but nothing changed. The fan will run, and outside, I could smell the propane. The igniter clicked 3 times, trying to ignite, but no go.
OK, the fact that the propane valve opens means that you have adequate air flow.
The fact that the ignitior sparked 3 times and quit means that it was not able to create a flame that the thermocouple could detect.
Could be something as simple as a piece of rust shorting the ignitor or a mud dobber's nest preventing proper mixture.
Reply #6 in link below may provide some guidance:
Random Questions on Heating (https://www.foreforums.com/index.php?topic=43382.msg436482#msg436482)
Ordered a new circuit board, and that didn't fix the problem. The burner head screen was rusted through. Ordered a new furnace burner head, and igniter just because I have it apart.
Now might be the time to get a new fan motor,yours will go out sooner or later,like you say it's already apart.
He'll need a longish hex key to get at those lock nuts in the middle of the fan.
***UPDATE***
So, I started with the circuit board, which was the easiest part to access. No change, so I pulled out the burner head, which was rusted, and since I was in there, replaced the igniter also. Still no change. Dug further and checked the sail switch and limit switch, and both showed good. Still wasn't working. Did a little more googling and found how to test the gas solenoids, and they also showed to be good. I blew out the gas valve without activating the solenoids once and it fired up once, but wouldn't do it again. Then, I activated each solenoid and blew out the valve each time, and put it all back together. It is now working as it should. It was a little time consuming but it was worth it.
Thanks for the tips and suggestions.
So, when you blew out the lines/gas valve, did you get an oily substance? Other?
I didn't really see anything, but I think it was probably some small particle that may have blocked a passage way. Nothing oily that I recall.
Way to hang in there.
Way to hang in there.
Propane leaves a sticky, oily, residue. The valves are gasketed caps that sit on the out flow stand pipes and are lifted off by electromagnets, and clamped back in place with gravity and light springs. IF the problem returns it's either clean that area thoroughly or replace the valve.
Art