Loud Snap from Trane XE1000 after I shut off power

Krell

It's a 14 year old Trane XE1000 heat pump / ac. I shut the power off to the unit at the circuit breaker, went out and removed the right side panel, just to clean out some debris and check things out in general. The power was off about 5 minutes, I had the side panel off, and wasn't touching anything at the time, and I heard a loud snap come from somewhere in the unit. A capacitor discharging? Sheet metal flexing since I took off the side panel? Everything still works fine. Just wondering about the snap. Any ideas?

Thanks

gregzoll

Most likely the contactor closed for the call to run a/c. You should always shut down both the inside & outside unit when working on either part.

Krell

Gregzoll, thanks for the response. I had turned the thermostat way up before I shut off the power to the heat pump, so the a/c wouldn't even try to come on. ???

gregzoll

Turning the thermostat up, does not shut power off to the air handler/furnace. The system is still alive, and can still send a 24v signal to the contactor for a call for cooling. Always shut off power to all units related to the hvac system you are working on. Keeping one or the other live, can cause problems, such as blown fuses on circuit boards, or danger to the person working on the system.

Krell

Thanks for that info. I did not know that.