ecobee

ecobee3 Lite - Is your system compatible?

The ecobee3 lite can support standard 24VAC controls:

Conventional HVAC Systems

  • up to 2-stages of forced air heating (W1, W2) and up to 2-stages of forced air cooling (Y1, Y2)

 

Heat-Pump HVAC Systems

  • up to 2-stages of compressor (Y1, Y2) and up to 2-stages of auxiliary heat (W1, W2).
  • O/B (Reversing valve change-over) is a configurable setting during the thermostat HVAC configuration.

 

Boiler Systems

  • up to 2-stages of heating (W1, W2)

The ecobee3 can support both a heating boiler and forced air cooling on the same thermostat. This is a 2-transformer configuration.

 

 

  • RH = 24VAC from heating transformer
  • RC = 24VAC from cooling transformer
  • C = Common of 24V transformer
  • G = Fan control
  • Y1 = 1st stage of compressor
  • Y2 = 2nd stage of compressor
  • W1(aux1) = 1st of heating(conventional systems) or 1st stage of auxiliary heat(heat-pump systems)
  • W2(aux2) = 2nd of heating(conventional systems) or 2nd stage of auxiliary heat(heat-pump systems)
  • O/B = Heat-pump reversing valve (RV) change-over. (O = engage RV on call for cooling / B = engage RV on call for heating)

 

Due to variations in other thermostat manufacturers, this is a guideline to determine if the existing thermostat terminal designations are compatible:

  • V+/V- > not compatible
  • VG+/VG- > not compatible
  • B > can be referred to as 24V(Common). If the existing thermostat already has a C(Common) wire then B refers to RV change-over
  • X > can be referred to as 24V(Common)....connect to C terminal
  • X2 > commonly referred to as auxiliary/emergency heat. If you do not have W1/W2  then this wire would connect to W1 on the ecobee3
  • E > commonly referred to as emergency heat. If you do not have W1/W2 then this wire would connect to W1 on the ecobee3. If you have W1/W2 then E wire is disconnected...it is not needed
  • G2 > ecobee3 only supports one fan relay...not supported
  • G3 > ecobee3 only support one fan relay...not supported
  • S1/S2 > these are applicable with some heat-pumps and connect to an outdoor temperature sensor. This is not needed, the ecobee3 utilized internet weather to accomplish the same functions...disconnect
  • L > heat-pump failure light. Not supported...disconnect
  • HUM > humidifier control. If you have only one wire connected to HUM then connect this to ACC+
  • OAT > outdoor ambient temperature sensor...not supported
  • SRTN > return air duct sensor...not supported

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