DIY & Home Improvement

I assume you have turned off the circuit breaker by now otherwise your outside compressor would be frozen all the way back to your inside coil if the fan isn’t running.

Problems like that are typically relatively minor electrical problems (versus a major problem like a burnt out compressor). Actually most havac problems are relatively minor electrical issues.

1.) it could be a bad thermostat shorted thereby constantly sending the 24 volts to the contactor switch in the outside unit/compressor. If you have a multimeter you can test the thermostat for proper operation. OR you can replace the thermostat with a cheapo (if you want to avoid a service call).


2.) It could be the low voltage line (the little brown wire that is usually taped to the copper lineset). It could be shorting sending constant 24 volts to the compressor contactor

3.) It could be the contactor switch in the compressor. The thermostat sends 24 volts to this magnetic switch which pulls in and energizes the 240 volts to the compressor. These get pitted or sometimes gummed up with bugs. It could be stuck.