Thermostat Wiring For Furnace And Ac

Breakdown of colors and terminals thermostat wiring diagram for ac unit.

Thermostat wiring for furnace and ac.

The transformer steps down 120 volts to the 24 volts the thermostat needs and sends out the 24 volts on two wires. C terminal to the blue wire. That will power the relay contactor or complete the circuit in the circuit board. Once your c wire is ready follow these steps to install your new thermostat.

Sometimes depending on the thermostat and the manufacturer the thermostat can be a dual heat pump thermostat. Thermostats use 24 volts ac from a transformer to control a furnace. Label where the wires are connected on the thermostat. The thermostat is likely a digital thermostat that requires the c wire or the common wire to provide power for the thermostat.

W terminal to the white wire. The heating system will likely be a gas or electric furnace. Always refer to your thermostat or equipment installation guides to verify proper wiring. Notesome ac systems will have a blue wire with a pink stripe in place of the yellow or y wire.

Y terminal to the yellow wire. Flip the furnace ac breaker to the off position. The yellow wires connect to the y terminals on your thermostat. The white wire underneath your thermostat connects to your heating system.

Red wire for air conditioner control power hot 1 the r terminal is the 24 volt hot feed from the control step down transformer. They control your air conditioning system. The white wire connects to terminal w in industry standard thermostats. Check to see if they match the industry standard listed above.

A thermostat with five wires typically controls an air conditioner with a heating system. Or it can be used for an air conditioner and gas furnace system depending on how the thermostat is wired. The two 24 volt wires go to the r terminal and c terminal inside the thermostat. Furnace 24 volt transformer.

G terminal to the green wire. Additionally it will require a different thermostat and different wiring than an air conditioner. 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. R terminal for the red wire.

The yellow wires underneath your thermostat connect to your compressor. It terminates at your air handler or furnace. This diagram is to be used as reference for the low voltage control wiring of your heating and ac system.