My ecobee3 Lite is not powering up after installation. What could be the reason?

If your ecobee3 lite isn’t powering on after installation, please check the following:

  • Are all your wires properly inserted into the terminal blocks at the thermostat? Tug on them to ensure they’re in place.
  • Make sure the R wire (either R, Rc, or Rh) is going to the Rc terminal only. If the wire is in the Rh terminal, the ecobee will not power up.


  • Ensure your power is turned on from the circuit breaker.
  • Some HVAC equipment have a safety switch that cuts power off if the cover panel isn’t shut properly. Ensure that it is.
  • If you’ve installed the Power Extender Kit, ensure the R wire is connected to Rc only. Ensure the G wire is inserted properly into the terminal.


  • If you have a multi-meter, please check the AC voltage between Rc and C (or Rh and C) to ensure it is 24V.

If your device still isn’t powering on, please contact our support team.

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