Hvac Wire Colors. This wire may be red without an h attached to it depending on if you have a dual transformer setup. The most common is 18 5 5 strand 18 gauge.
Some hvac systems will have a two transformer set up. Traditional hvac wiring in homes uses four or more wires one of which is called the common wire or c wire. R wire red for power.
R wire red for power.
Blue yellow green white and red. Furthermore for the thermostat wiring colors code for this terminal if equipped consult with the installer or trace the wire out to the source. It is important to note that with this type of wiring there are multiple phases in place each of which will get its own color wire to make it clear what it is for those working on it. R wire red for power.
