Question I wired together yellow of the cooling circuit and blue(common) before turning off the indoor air handler unit and ended up shorting out the transformer. As I was going to replace the transformer,I thought I cut off the breaker and ended up having the transformer explode (just a little pop). Now that I've replaced the old transformer with the new one I can't get anything to come on at all.This is a old trane heatpump/airhandler split system (23yrs old)which has only one relay inside for heat/cool/and fan.Could the relay be bad
Answer What was the original problem that had you tying the wires together? If the air handler has auxiliary electric heat you may have more than 1 breaker to turn off to cut all power to the air handler. You really haven't given me enough information to be of much help to you.
