Re: Replace Thermostat Wire from 2 to 3 conductors
I answered this in another thread. Yes, just replace the 2 wire cable with a 3 wire cable. A 2 wire supplies power to the switch in the thermostat and a return. With a digital thermostat you need power on common from the transformer to supply power to the electronics and power to the switch and a return. The "C" connection is the common side of the transformer. It is much like adding neutral to a wall switch to use a digital control.
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