Page 4Overview
Heat Pump HVAC System Wiring
Terminal Marking Meaning Typical Wire Color
Record the old thermostat wire
connections and
terminal marking here
C 24VAC Common Blue
R 24VAC Return Red
G Fan Green
W or W1 Aux Heat White
Y or Y1 Compressor stage 1 Yellow
O (or B*) Change Over Valve Orange (brown*)
Y2 Compressor stage 2 Black
If you have a terminal marked “B” with a brown wire attached to it, that means you have a changeover (C/O) with heating
type heat pump system. Be sure to set the change over type in the Installer Settings menu to C/O Type: w/ Heat.
Otherwise, leave it set to w/ Cool.
Standard HVAC System Wiring
Terminal Marking Meaning Typical Wire Color
Record the old thermostat wire
connections and
terminal marking here
C 24VAC Common Blue
R 24VAC Return Red
G Fan Green
W or W1 Heat stage 1 White
Y or Y1 Cool stage 1 Yellow
W2 Heat stage 2 Orange
Y2 Cool stage 2 Black
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