Connect it to the C terminal in the furnace/air handler and the C terminal in the thermostat. Remember to turn off power to the furnace before opening its cover(s). Use the G wire (usually green) as the C wire.

What is the thermostat connected to?

Four wires come to the centrally-located thermostat from the main heating/cooling unit (usually located in a closet, basement, or occasionally in the attic): One wire, usually red, supplies 24 volts AC power to the thermostat, while the other three supply control signals from the thermostat, usually white for heat,

Where is thermostat installed?

0:364:06How To Install a Programmable Thermostat | The Home Depot YouTubeStart of suggested clipEnd of suggested clipYou can remove the thermostat from the wall by simply unscrewing the mounting hardware. Once youveMoreYou can remove the thermostat from the wall by simply unscrewing the mounting hardware. Once youve removed the cover place a piece of tape on each of the wires with the letter code of the terminal.

Where does W2 wire go on thermostat?

W - This is the thermostat terminal for heating. This wire should go directly to the heating source whether it be a gas or oil furnace, electric furnace, or boiler. White for W Terminal. W2 - This is the thermostat terminal used for second stage heat.