We will need to call an HVAC professional to assess the damage and fix our unit, but in the meantime, I'm wondering if this is a big coincidence, or if the new thermostat is related to the external unit not working. Any advice is welcome! Thank you.

On Monday, the BGE contracted tech (who, btw, is actually a computer repair person, not an HVAC person), installed the BGE Peak Rewards thermostat in our home. It replaced our old mercury thermostat.

Weather has been cool, and we've had the windows open until this past Friday. The fan was blowing air, but the temp of the house kept rising. We realized our external unit was not coming on.

We called BGE and they sent a tech who told us that the thermostat was reading that it was sending the correct voltage to the fan and heat pump. He checked our circuit breakers and said he thought the heat pump circuit breaker was bad and that we should replace it. While the circuit breaker was not reading as blown, it would not click firmly into the on position.

We figured that it was worth a shot and replaced that circuit breaker this morning. Tried to turn the AC on again. I heard the outside unit make a terrible bang, then a hum/whine, and it smelled like smoke. I thought it was on fire, but thank goodness it was not.

We immediately cut the electricity and called BGE.

They have refused to send a tech b/c this is an "HVAC problem" and they only service the thermostat.

We had NO problems with our HVAC until the thermostat was installed. I have a hunch these are somehow related, but I don't know how. It just seems to strange a coincidence. We will have to have an independent HVAC company come out anyway, b/c I'm afraid either the transformer on the unit blew, or the entire unit is messed up now.

I'm just curious what you all think about the possibility that the thermostat install could mess up the external unit but not the fan?