Nest thermostat star terminal

A Nest thermostat’s star 👁 Star connector icon
or 👁 Star connector icon
O/B terminal can be used to control several different system functions, depending on what type of system you have. For example, you can use the star terminal to connect a wire that controls a humidifier or dehumidifier, or emergency heat.

• During setup, the app will give you a custom wiring diagram to install your Nest thermostat. You should only insert a wire into the thermostat’s star terminal if the wiring diagram tells you to.
• If the app instructs you to connect a wire to the star 👁 Star connector icon
  terminal during setup, the thermostat will prompt you to identify the wire and its function.
• No matter which Nest thermostat you have, you can only put one wire into the star 👁 Star connector icon
  terminal, so only one function is supported at a time.
• If you upgrade to a new thermostat, you'll be asked what equipment is connected to the star 👁 Star connector icon
  terminal. If you're unsure, exit the setup flow and check your previous thermostat's wiring. Go to Devices 👁 and then
  your device's tile 👁 and then
  Settings 👁 Settings gear
  👁 Image
  Thermostat 👁 Image
  Wiring.
  • Optional: To check the wiring from the thermostat, go to Settings 👁 Settings gear
    👁 and then
    Equipment.

Important: If you’ve connected a humidifier, dehumidifier, or multi-speed fan wire to the star terminal, we strongly recommend that you get help from a pro.

👁 Thermostat wire connectors with labels