Hello,

My thermostat works fine and the burners come on. I can hear the fan start but it immediately cuts off then the burners shut off. Then I can hear a humming sound for about 3 or 4 minutes and it goes away.

It could be the run capacitor going bad or just the motor going bad. The run capacitor should have two brown wires going to it from the motor and mounted on or close to the blower housing