After the air is on for about two minutes the circuit breaker pops off.

First, see if you get the same result when you run the machine on "Air-Fluff." If you don't pop the breaker on Air -Fluff you know the problem is originating in the heat circuit, get inside the machine and inspect the wiring for crispy/burned terminals and the heat element for damage or contact with the housing... If it does pop the breaker on Air-Fluff: Inspect the terminal block on the back of the unit where the power cord is bolted on (with the unit unplugged), look for any scorched spots- if that is clear, remove the outlet cover and inspect the wire connections on it for scorching (with the circuit break off). Can't be more specific without a model #!
Help Me Find My Model Number RepairClinic com

The best guess is that you have a bad thermostat. When the compressor shuts off it has to stay off for a long enough period of time for the low pressure high pressure to equalize. If it turns the compressor off and back on immediately it can't start against the heavy load created by these unequal pressures. If it will start every time after sitting for 10 minutes the thermostat is making it short cycle.

If the motor circuit breaker is popping off as you state, it's either bad or the power supply is inadequate. It's not all that rare for the circuit breakers on electric motors to go bad. When they go bad they either won't reset or pop off at lower and lower amperages. Another cause could be that the motor is essentially trying to pull too much electricity through a line that can't handle it. This would be caused by using too many, to long or too small guage extension cords. Always plug the compressor into an outlet and run longer air lines than use extension cords. On some occasions if you are too far from the breaker box and the lines to the outlet are low guage you can get the same affect.

Something is shorted out. Leave the breaker off until you find it. You need an ohmmeter to find it, but look for the black marks for a hint.

i think there may be damage to a small electrical component in the circuit board which probably fried just before breaker popped open

Two things that you could check: 1) If you have access to an ampmeter, determine if the unit is drawing over over 14 or 15 amps, 2) replace the suspect circuit breaker in case it is beginning to go bad. Breakers only trip for overcurrent conditions or failure of the breaker itself. If it is pulling close to 15 amps, then it could heat up over time and trip.

Hi,

Here is a tip that I wrote that will help you ti find out why the circuitbreaker is tripping.

Circuit Breaker Keeps Tripping
heatman101

You have a ground fault or short . Disconnect dryer and remove small panel that holds the cord. Check if any wires are frayed, loose or touching any other metal objects.

Start capacitor, fan motor or the compressor is worn out. Most times its start capacitor. Thanks, Sea Breeze

Furnace. To confirm use an Ampprobe or other brand ampmeter and see how much current is being drawn. If it is more that 80% of the breaker rating, it si for sure the Furnace.