Thermostat Wiring For Furnace And Ac

The yellow wires underneath your thermostat connect to your compressor.

Thermostat wiring for furnace and ac.

A thermostat with five wires typically controls an air conditioner with a heating system. It terminates at your air handler or furnace. Always refer to your thermostat or equipment installation guides to verify proper wiring. Furnace 24 volt transformer.

The white wire connects to terminal w in industry standard thermostats. Red wire for air conditioner control power hot 1 the r terminal is the 24 volt hot feed from the control step down transformer. That will power the relay contactor or complete the circuit in the circuit board. Y terminal to the yellow wire.

C terminal to the blue wire. Once your c wire is ready follow these steps to install your new thermostat. Breakdown of colors and terminals thermostat wiring diagram for ac unit. R terminal for the red wire.

Flip the furnace ac breaker to the off position. Label where the wires are connected on the thermostat. The transformer steps down 120 volts to the 24 volts the thermostat needs and sends out the 24 volts on two wires. The two 24 volt wires go to the r terminal and c terminal inside the thermostat.

The white wire underneath your thermostat connects to your heating system. Notesome ac systems will have a blue wire with a pink stripe in place of the yellow or y wire. W terminal to the white wire. In the most basic system this functionality is provided by use of a fan center relay and the low voltage wiring to the thermostat now will require a minimum of three wires for heat only.

This function allows you to circulate the air in the house by using the fan in the furnace without heating or cooling the air moving through the system. They control your air conditioning system. The yellow wires terminate at your compressor contactor via an air handler. Check to see if they match the industry standard listed above.

This diagram is to be used as reference for the low voltage control wiring of your heating and ac system. The thermostat is likely a digital thermostat that requires the c wire or the common wire to provide power for the thermostat. Additionally it will require a different thermostat and different wiring than an air conditioner. The heating system will likely be a gas or electric furnace.

Or it can be used for an air conditioner and gas furnace system depending on how the thermostat is wired. G terminal to the green wire. Thermostats use 24 volts ac from a transformer to control a furnace.