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Step 5. Label the Wires with Tags
Carefully disconnect and label the wires from your old themostat one wire at a
time, using the label (label 1 )provided.
Step 4. Take a photo
Take a picture of the wires connected to the terminal of your old thermostat. You
may need to reference this photo later on.
Terminal designation:
Terminals
What it means
RC
24VAC primary for cooling
RH
24VAC primary for heating
W1
1st stage Primary heating relay / Aux heat
W2
2nd stage Secondary heating relay / Aux heat
Y1
1st stage Primary cooling compressor contactor
Y2
2nd stage Secondary cooling compressor contactor
G
Fan relay
C
24VAC common*
O/B
Changeover valve for heat pumps
S
Wiring Module Connection
*
Multiple use reserved, including but not limited to: emergency heat
line, humidifier control
