I have a 2.5 ton Ducane heat pump with electric backup heat. The other day my air handler stopped running (turns out it just tripped a breaker). I reset the breaker and now I can't get the air handler and compressor to run at the same time. The outside unit will run no problems, but the fan inside will not kick on. However when I take the cover off the thermostat (to make sure all my wires are tight) the air handler kicks on, but the outside unit will not run. Anyone have any ideas of what's wrong?

I wonder why the breaker tripped in the first place. Try this: set the thermostat fan selector to ON & raise set temperature to turn heating on. Do indoor fan & outdoor unit now run together?

KC13, thanks for your response, I tried that the other day, and the unit would not come on. Is there any chance this is the thermostat? I bought a new one and plan to try to install it when I get home

The thermostat could be malfunctioning, but I am concerned as to why this problem surfaced after the breaker tripped & was reset. Circuit breakers rarely trip for no reason - there could be a bigger problem waiting to ruin another thermostat.