How to Replace a 4 Wire Thermostat
- 1). Disconnect all power to the HVAC unit. The easiest way to do this is to turn the breaker off in the circuit breaker panel.
- 2). Remove the old thermostat from the wall by gently pulling on it. Disconnect the thermostat wires from it and label the wires according to which terminal they went to. Typical four wire thermostats use the red, white, green, and yellow wires which go to the "R", "W", "G" and "Y" terminals respectively.
- 3). Unscrew the old thermostat wall plate from the wall and discard. Mount the new thermostat wall plate to the wall using drywall anchors and screws. Check to see that it is level.
- 4). Look at the wires to see if there is approximately 1/4 inch of bare copper exposed at the ends. You may need to trim them back or strip more off to achieve this.
- 5). Connect each thermostat wire up to the correct terminal. Refer to the labels that you created in step two. Push the thermostat on to the wall plate gently until it "clicks" into place.
- 6). Go to the circuit breaker panel and turn the power to the HVAC unit back on. Adjust your thermostat's setting to the temperature you desire.
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