T4000ES Learning Thermostat E (White)
The Thermostat E works with 85% of 24V heating and cooling systems, including gas, electric, forced air, heat pump, radiant, oil, hot water, solar and geothermal. Heating and Cooling: 1 stage of heating (W1) and cooling (Y1) and a second stage of either heating (W2) or cooling (Y2).
Heat pump: with auxiliary and emergency heat (O/B, AUX) Fan (G)
Power (C, Rh or Rc)
The Thermostat E is designed to work even if your home doesn't have a common (C) wire, but installing a new C wire may be required.