My furnace gets the signal from the thermostat, then about half of the time, the inducer motor whirrs on and off over and over. Sometimes it runs continuously without ever lighting.
When I open it up, hold down the cover button and tap the circuit board the light on the board comes back on and the furnace works normally.
I replaced the circuit board last year but the problem persists. I'm assuming there's a bad connection somewhere – where should I look?
Best Answer
Tracking down an intermittent problem like this requires being careful and methodical.
First, take Ed Beal's suggestion pull the switch out so the furnace runs without the cover. Then, start tracking results. Are you sure that tapping the circuit board fixes it? How about wiggling the wires, one by one? Or, can you cause the problem to occur (not go away) by wiggling something?
Eventually you'll narrow it down to the flaky component, but it may take a while. Good luck.