The common wire sometimes referred to as the c wire is whats responsible for delivering constant power to your thermostat. I dont get into heating systems so am at a loss but would like to send him some information if any of you guys can help.
Thermostat Wikipedia
Pipe thermostat wiring diagram. Color of wire and termination. R the r terminal is the power. 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. Thermostat wiring diagrams for heat pumps heat pump thermostat wire diagrams. Heat pumps are different than air conditioners because a heat pump uses the process of refrigeration to heat and coolwhile an air conditioner uses the process of refrigeration to only cool the central air conditioner will usually be paired with a gas furnace an electric furnace or some other method of heating. Thermostat wiring and wire color chart thermostat wiring colors code.
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. A friend has just rang from abroad asking how to wire up the above thermostat. The diagram below shows how a basic 4 wire thermostat is connected as indicated by the color code chart above. This thermostat has 3 terminals c. The basic heat ac system thermostat typically utilizes only 5 terminals. At left the thermostat wiring diagram illustrates use of a honeywell t87f thermostat in a 2 wire application controlling a gas fired heating appliance.
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. He wants to use it to switch onoff a pump. In the honeywell t87f thermostat series the single pole double throw switch makes closes one set of contacts when the temperature falls to turn on the heating appliance.
Gallery of Pipe Thermostat Wiring Diagram
