Thermostat Wiring For Furnace And Ac

A thermostat with five wires typically controls an air conditioner with a heating system.

Thermostat wiring for furnace and ac.

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. The yellow wires underneath your thermostat connect to your compressor. The transformer steps down 120 volts to the 24 volts the thermostat needs and sends out the 24 volts on two wires.

Turn off your existing thermostat. Flip the furnace ac breaker to the off position. 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.

The white wire connects to terminal w in industry standard thermostats. 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. The yellow wires connect to the y terminals on your thermostat. R terminal for the red wire.

That will power the relay contactor or complete the circuit in the circuit board. Always refer to your thermostat or equipment installation guides to verify proper wiring. Once your c wire is ready follow these steps to install your new thermostat. G terminal to the green wire.

Thermostats use 24 volts ac from a transformer to control a furnace. It terminates at your air handler or furnace. Label where the wires are connected on the thermostat. 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.

C terminal to the blue wire. This diagram is to be used as reference for the low voltage control wiring of your heating and ac system. The heating system will likely be a gas or electric furnace. The yellow wires terminate at your compressor contactor via an air handler.

The thermostat is likely a digital thermostat that requires the c wire or the common wire to provide power for the thermostat. Check to see if they match the industry standard listed above. Additionally it will require a different thermostat and different wiring than an air conditioner. Red wire for air conditioner control power hot 1 the r terminal is the 24 volt hot feed from the control step down transformer.

Furnace 24 volt transformer. They control your air conditioning system. Sometimes depending on the thermostat and the manufacturer the thermostat can be a dual heat pump thermostat.