I am hoping someone has some experience troubleshooting furnace problems.
My furnace has just started doing the following...
The venting motor starts, then the igniter glows and the burner fires up to preheat the exchanger, but right when you would expect the fan to start the flame goes out and the process starts over again right away.
I know the fan is working (I can switch the fan on from the thermostat) and the filter is new. Because the fan is not coming on i know it is not a matter of too many vents closed.
If I monkey with it and reset it it seems to start working again?
this last time I blew it out carefully with compressed air and pulled the flame sensor and cleaned it (although it did not seem very badly soiled/oxidized)?
Circuit board, or maybe the internal heat protection cut off?
Thanks in advance for any help!