Thermostat Wire Diagram. These diagrams depict some commonly used and frequently installed configurations but may not match your hvac system. By contrast here is a thermostat that is being powered with the furnace transformer with a c wire or c wire adapter.
Custom wiring diagram that you will need to install your nest thermostat. If your thermostat has jumpers remove them but save them along with your old thermostat. For five wires g fan green r 24 vacrrc red c 24 vac common blue brown or purple are the most common y compressorair conditioner yellow w heat white.
For five wires g fan green r 24 vacrrc red c 24 vac common blue brown or purple are the most common y compressorair conditioner yellow w heat white.
One is for cool and the other is for heat hence the abbreviation rh and rc. Blue this is your common or c wire. The wire that connects to the y terminal is yellow and connects to the compressor in your cooling system. Orange this wire connects to your heat pump if you have one.