Atwood 7920 Furnace Issues - Electrode not sparking
Hi there,
I am having issues getting my furnace's electrode to spark. Initial symptom was the furnace powering up the fan, attempting to ignite, and failing. It is in a '96 Elkhorn truck camper, furnace is an Atwood 7920-ii Hydroflame.
I took the furnace out and gave it a thorough cleaning - had dust bunnies all around sail switch and a few dead bugs in the burner head/around the propane orifice.
Tried again after cleaning and same issue. Determined issue was likely the electrode and went from there. While purchasing a new electrode I also purchased and changed the sail switch and high-limit temp switch; still no fix.
My old circuit board was not giving the proper 3-blink error code after going into lockout. It would also make a strange ticking sound during the period where the high-voltage line to the electrode would be receiving power. Replaced the circuit board with a new one. The ticking sound is gone and the board displays the proper 3-blink error code after "ignition lockout mode".
Through testing with a multimeter, there is 12V everywhere it should be/when it should be there (relay, high-limit switch, circuit board connections, propane solenoids). I noticed there is about 20 ohms resistance between the coils on the propane valve - several places say this is normal but the Atwood troubleshooting manual says they should be above 30ohms. I would return to this as a potential issue if the electrode was firing.
I have read every post I could find on several forums and talked to a couple RV techs on the phone, and everyone suggests that this issue is either circuit board or electrode.
My only guess at this point is that the circuit board arrived DOA. My assumption now is that the issue was always the circuit board, and the new one is defective also (I bought a $50 cheapy board). I have now ordered a Dinosaur Board and sent up a couple prayers.
No heat in the winter in Canada is less than ideal! Any help would be appreciated.
