My heater start working fine , the flame comes on, the fan runs well and blows hot air, then when the flame cames off, the fan continues to running blowing cold air and the never stop, blowing cold aiir the rest of the time? I changed the fan and the capacitor, Is it a heat sensor? What can be the problem?

Starts working fine and fan never stops ( night and day brand) thanks

Sounds like fan control,, if you kill the power to furnace and back on again does it keep blowing cold air or does it start over with flame on blowing hot air then continue to blow cold after flame goes out

Thanks I will kill the power to the entire furnace, is the fan control in the electronic board?