Honeywell Thermostat Color Coded Wire. R the r terminal is the power. Typically a furnace plus a c hvac system has four or five thermostat wires and a common wire.
It s important to note that in some cases the color of the wire does not necessarily mean it connects to that came color one the board. 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. These colors are used as follows.
The thermostat wire is color coded so the technician can identity which wire goes to which port on each board.
Next let s talk about the c or common wire. Thermostat wiring color code. In some cases one of those wires may be your common. But here is a list of the most common wire color to function mappings as seen in many four and five wire t stat setups.
