R the r terminal is the power. With the top thermostat wiring diagram showing an air conditioning system.

Master Electronics Repair Hvac Thermostat Wiring Diagram
Hvac wiring diagram thermostat. For programmable thermostats and smart thermostats c wires are essential for setting a schedule or having your heat or air conditioner turn on at a desired temperaturewhile some units can run without a c wire even brands like nest recommend having one for optimal. It is a red wire and comes from the transformer usually located in the air handler for split systems but you may find the transformer in the condensing unit. Red now there can be two separate wires for this. The color of wire r is usually red and c is black. By the use of an adjustable set point the job of the thermostat is to turn on either the heating or cooling system to maintain the desired room temperature in the home and to turn off the system when the desired temperature is achieved. These two connections will ensure that there is power to the thermostat that you are operating.
The thermostat is the control device that provides a simple user interface with the internal workings of your homes climate control system. Green the green wire connects to the fan. Moreover the heat source for a basic ac system can include heat strips for electric heat or even a hot water coil inside the. Orange this wire connects to your heat pump if you have one. As shown in the diagram you will need to power up the thermostat and the 24v ac power is connected to the r and c terminals. C is known as the common terminal.
Rc red wire power 24 vac rh or 4 red wire jumpered power 24 vac w white wire for heating enable y yellow wire for cooling enable g green wire controls fan on auto the diagram shows how the wiring works. Heat pump thermostat wiring a typical wire color and terminal diagram. Color of wire and termination. Finally the third thermostat diagram showing the average type of split system with an air conditioner or gas or oil furnace used for heating. My paperback and e book. For example if the red wire is connected to w on the thermostat the furnace should turn on.
Furnace thermostat wiring diagram terminal letters on a thermostat and what they control the hot wire 24 volts usually red from the transformer is the main power wire to turn on or off a furnace components. The second wiring diagram showing a heat pump system. How to wire an air conditioner for control 5 wires the diagram below includes the typical control wiring for a conventional central air conditioning systemfurthermore it includes a thermostat a condenser and an air handler with a heat source. White the white wire is what connects to the auxiliary heat on your system. Thermostat wiring and wire color chart thermostat wiring colors code. The common wire sometimes referred to as the c wire is whats responsible for delivering constant power to your thermostat.
Yellow the yellow wire connects to your compressor. The basic heat ac system thermostat typically utilizes only 5 terminals.