8
Terminal designation:
Terminals
What it means
RC
24VAC primary for cooling
RH
24VAC primary for heating
C
24VAC common
W1
1st stage Primary heating relay / Aux heat
W2
2nd stage Secondary heating relay / Aux heat
Y1
1st stage Primary compressor contactor
Y2
2nd stage Secondary compressor contactor
G
Fan relay
O/B
Changeover valve for heat pumps
S
Optional wiring module terminal to combine Y and G, while
reserve an extra in-wall wire to power on the thermostat
Do you have a C wire connected to your old thermostat?
3-2 Connect wires
RC RH G
C
Y1 Y2 W1W2
O/B
RC
G
Y1
W1
C
YES
→
3-2-1
NO
→
3-2-2
