nest Learning - Heat Pump Wiring Diagrams; 1 Stage Heat Pump Configurations

Wiring Diagrams: Heat Pump Systems
1 Stage Heat Pump
Label:
Function:

Y1
Compressor Relay (Stage 1)
Y2
Compressor Relay (Stage 2), 2nd-speed fan
relay
G
Fan Relay*
O/B
Heat Pump Changeover Valve
Rc
24VAC power from cooling transformer
W1
Heat Relay (Stage 1)
W2/AUX
Heat Relay (Stage 2) / Auxiliary Heat Relay
C
24VAC Common Wire †
*
Star: W3, E, HUM/DHUM, 3rd-speed fan relay
Rh
24VAC power from heating transformer ‡

1 Stage Heat Pump with Aux Heat

Label:
Function:

Y1
Compressor Relay (Stage 1)
Y2
Compressor Relay (Stage 2), 2nd-speed fan
relay
G
Fan Relay*
O/B
Heat Pump Changeover Valve
Rc
24VAC power from cooling transformer
W1
Heat Relay (Stage 1)
W2/AUX
Heat Relay (Stage 2) / Auxiliary Heat Relay
C
24VAC Common Wire †
*
Star: W3, E, HUM/DHUM, 3rd-speed fan relay
Rh
24VAC power from heating transformer ‡




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