What is the X-terminal on a thermostat?

Answer by  leninprakash (16)

The x terminal is usually a black wire connected to outside temperature sensor.It is the only thing it will be used for.if you don't have an x terminal on your new thermostat you can hook it up to the c terminal.Like I said it is usually a black wire.

Answer by  kennethjgoodson (4903)

The x terminal ix usually a black wire connected to an outside temperature sensor. It is the only thing it will be used for and if you don't have an x terminal on your new thermostat you can hook it up to the c terminal. Like I said it is usually a black wire.

Answer by  alphids (23)

The x-terminal is a black wire connected to external temperature sensor leading to the regular defrosting of the condensing unit.

Answer by  kipcat (1964)

The x-terminal on older thermostats is a throw-over from the heat pump introduction. It is usually used for some auxillary function. On old GE units, it was used to shift the reversing valve. On newer units, it's sometimes used to force a defrost of the condensing unit.