Supported wiring
Nest Learning Thermostat 2nd Generation
Nest Learning Thermostat 2nd Generation
Nest Learning Thermostat 2nd Generation
Nest Learning Thermostat 2nd Generation
Conventional connectors
Conventional connectors
Heat pump connectors
Heat pump connectors
Y1
Stage 1 compressor relay
Y1
Stage 1 compressor relay
Y2
Stage 2 compressor relay
Y2
Stage 2 compressor relay
G
Fan relay
G
Fan relay
O/B
Not used
O/B
Changeover valve relay
Rc
24VAC power from cooling transformer*
Rc
Not used
W1
Stage 1 heat relay
W1
Stage 1 heat relay
W2/AUX
Stage 2 heat relay
W2/AUX
Auxiliary heat relay
C
24VAC common wire.
C
24VAC common wire.
*
Stage 3 heat (W3), humidification (HUM), or
dehumidification (DEHUM)
*
Emergency heat (E), humidification (HUM), or
dehumidification (DEHUM)
Rh
24VAC power from heating transformer*
Rh
24VAC power from transformer*
* No jumper wires required. You don’t need to hang on to any old jumper wires going from Rh (sometimes
just called R) to Rc. Nest will automatically jump these two connectors.
Nest Learning Thermostat installation & configuration guide
Page 6