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.

Thermostat wiring for furnace and ac.

The yellow wires terminate at your compressor contactor via an air handler. Check to see if they match the industry standard listed above. The thermostat is likely a digital thermostat that requires the c wire or the common wire to provide power for the thermostat. The yellow wires connect to the y terminals on your thermostat.

It terminates at your air handler or furnace. Y terminal to the yellow wire. The white wire connects to terminal w in industry standard thermostats. Thermostats use 24 volts ac from a transformer to control a furnace.

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. The two 24 volt wires go to the r terminal and c terminal inside the thermostat. A thermostat with five wires typically controls an air conditioner with a 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. That will power the relay contactor or complete the circuit in the circuit board. Turn off your existing thermostat. G terminal to the green wire.

C terminal to the blue wire. 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. The heating system will likely be a gas or electric furnace. The white wire underneath your thermostat connects to your heating system.

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. They control your air conditioning system. W terminal to the white wire. Additionally it will require a different thermostat and different wiring than an air conditioner.

This diagram is to be used as reference for the low voltage control wiring of your heating and ac system. R terminal for the red wire. Once your c wire is ready follow these steps to install your new thermostat. Furnace 24 volt transformer.

Breakdown of colors and terminals thermostat wiring diagram for ac unit. Label where the wires are connected on the thermostat. Notesome ac systems will have a blue wire with a pink stripe in place of the yellow or y wire.