Heater thermostat wiring color code Thermostat wiring color code wire heat pump diagram ac heater heil unit coloring Thermostat wiring diagram mean letters wire 2wire only where ifixit thermostats which goes
What all those letters mean on your thermostat’s wiring
Heater Thermostat Wiring Color Code
What All Those Letters Mean on Your Thermostat’s Wiring - iFixit