Have HVAC Questions? Ask an HVAC Expert for Answers
Can you give me complete model from inside furnace in burner compartment so I can provide guidance with this specific unit.Model will be on a label just above burners on right or left inside panel
Excellent, now while I am pulling a service manual, tell me if there is a flashing light on control board and if so pattern of flash.
Sorry I see that now. Does gas valve and burners shut down properly?
Do you have a meter to see if the voltage is staying constant to the gas valve relay when it shuts down?
We will need a meter to check micro amps on flame rod.Below is a generic video showing how to do this. Either flame rod is not sending signal to board, we have a bad connection at flame rod or board or or board is bad, not reading micro amps from flame sensor.
Disregard last chart. This is correct chart showing low flame sense
What we do is put the meter is series. Disconnect the wire from flame sensor and connect it to one lead on meter.Put other meter lead on flame sensor where you unplugged wire.
Are you sure meter was set on micro amps?
Hmm that is a bit strange,that we got no reading, but when you disconnected we lost signal to valve.Sounds like we were getting some signal through to board
I am still here.Got called away from desk, Lets clean terminal on flame senser and reconnect.Maybe we had a bad connection.See if it will stay on and also check at board to make sue we have good connection
I understand. Sometimes it is less expensive just to call in a tech.If flame sensor is new , in flame good, wiring and connections good, I suspect failing board.
I would go ahead and replace board