NEED ASSISTANCE... ATWOOD AFMD FURNACE
I have a 2018 class A gas unit with an Atwood afm series furnace. My problem is that it was sooting up and smelling, even to the point of sounding off the CO alarm. I thought I had a dirt dauber probl...
Forum Discussion
VilleDeal wrote:
I have now tested the limit switch and it is closed as it should be.
I have also tested the off/reset switch and have resistance when it is on reset and have no resistance when it is off which should also be correct.
I do have 12 volts to the board, so am I to suppose I need to replaced the circuit board at this point do you reckon?
You stated the sail switch is closed "as it should be"
My Atwood 8531 sail switch is normally open when the furnace is not running. When the thermostat calls for heat one of the pre checks is looking for an open circuit on the sail switch. If it's found closed the board goes into lockout. No fan, nothing.
3rd poster provided a link, open link and scroll down to the wiring schematic. Sail Switch N.O. (normally open).
Any diagnostic codes from the ignitor board?
Even a failing sail switch can look good using a volt meter. My rear furnace would occasionally not run when calling for heat. Dyno board flashing a sail switch closed error. I pulled sail switch and it tested good. Purchased sail switch, installed and now furnace starts when called for heat.
