Atwood 7920-II issues

Question

Hey all, so had the camper out last weekend. All great except my furnace wouldn't work. I turn the switch on the thermostat, nothing. No blower motor, no clicking of ignition, no nothing. The LED doesn't blink, doesn't come on at all. Broke out the tester and as far as I can tell, Its getting proper voltage. I did flick the breaker in the by the board. I also checked both fuses (panel and by battery) no dice.

Fresh out of ideas. I have propane, stove works, bbq works. hot water heater works, although after heating, my pilot goes out (whole other issue I'm confused about) so not sure whats going on with the furnace. Worked the few times I used it last year.

westend · Answer

Got meter? Look for voltage present at thermostat and at power connections on circuit board. Sometimes, the connector to the board will oxidize and then, no electrons flow. I've read that using an eraser on the contacts cleans them but I use Caig Deoxit, an electronic spray.

old-biscuit · Answer

That in-line breaker/switch by board.......
Got to have 12V DC power to and thru it.
12V DC power should be present all the time on that part of circuit.
Power comes from DC Dist Panel to & thru that breaker/switch to the timed delay relay. When t-stat contacts make up......power will then go to fan motor on that circuit.

roscopcoletrain · Answer

Thanks. Doesnt seem like I have power to thermostat. I had a new digital one laying around and hooked that up and it had no power. My father is going to pop over with his meter later today and we'll have a look. Not great at electric stuff  myself lol, but always willing to learn :)

old-biscuit · Answer

The DC fuse that supplies power to that circuit breaker/switch on furnace is same place the red wire on t-stat gets power.
After t-stat contacts make up....power then goes to timed delay relay to allow power to go to fan motor

roscopcoletrain · Answer

So all is working now. Took thermostat off, cleaned it up some, took off some of the wires on the board, going and just plugged everything back in. tada, furnace is working like a champ again. So I'm not sure why. The LED started working again as well. So we'll see if it was a temporary thing or what.

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Atwood 7920-II issues

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