Nest Learning Thermostat connects to HVAC systems via standard thermostat wire terminals accepting R Rc G Y W C and other 18-24 AWG low-voltage thermostat wiring for heating cooling and fan control.
| Pin | Name | Function | Type |
|---|---|---|---|
| R | R | 24V AC power hot | PWR |
| C | C | Common 24V AC return | GND |
| G | G | Fan control relay | I/O |
| Y | Y | Cooling call compressor | I/O |
| W | W | Heating call furnace | I/O |
| O | O | Heat pump reversing valve cooling | I/O |
| B | B | Heat pump reversing valve heating | I/O |
Nest Learning Thermostat connects to HVAC systems via standard thermostat wire terminals accepting R Rc G Y W C and other 18-24 AWG low-voltage thermostat wiring for heating cooling and fan control.