My Hvac fan won't stop even after the desired heat is reached after the gas burning stops. I changed the furnace limit switch, no difference. Today I noticed there is an auxiliary limit switch on top of the furnace. From what I read so far it is for shutdown in case of overheating.
The fan stops some times after desired heating is reached, not most of the times. Needless to say my electric bill is bloated, my guess is because of the fan running unnecessarily for long times.
I did install a new nest thermostat and ruled out its thermostat issues with Nest help.
My next guess is some capacitors on the board are blown, to replace the board? the board itself is shielded in a box of sheet metal where all the wires are fed into.
The furnace is made by Carrier, model 396JAW036045. 30+Yr old.
Any help is appreciated. Thanks in advance.