Ive done my best to read through the forums to figure this out but Im kinda stumped.
The furnace ran for a sort time today and shut down. Went to check on it and the LED lights were flashing alternately slowly so I pulled the ignitor and flame sensor to clean but now it won't run at all and the ignitor doesn't glow. The difference this time is that only the secondary led stays lit and the first led is off which -
"pressure switch is open or has opened 5 times during a singe call for heat"
- blocked inlet/exhaust vent; OR condensate line blocked;
- Pressure switch closed prior to activation of combustion air blower
When I try to start the furnace by jumping R & W it'll start the inducer motor, I can hear the pressure switch engage, and then it'll shut down after running for a while and giving me that slow flashing secondary led.
Things I've checked/done so far.
1) Cleaned ignitor and flame sensor with steel wool.
2) Ignitor ohm'd out at 17ohms. Is that normal?
3) Transformer gets 120v and puts out 27v
4) I get 120v to the inducer motor
5) I get 25V between C & R & C & W
6) Checked the vacuum line for obstructions
7) Used a drill bit to clear the nozzle on the inducer motor
8) I get continuity on the pressure switch and can hear it click when the inducer motor spools up to speed
I still have to take the vent pipe off to see if there is anything stuck in the vent pipe but from the outside it doesn't look like anything could have gotten inside due to the exterior screen.