Nest Support

Questions about Nest Learning Thermostat or Nest Protect: Smoke + CO alarm? We've got answers, videos, and plenty of resources to help you out.

My heat pump cools when it is supposed to be heating

If your heating and cooling system is a heat pump and it blows cool air when your Nest Learning Thermostat is in heating mode (the background on the display is red), you may need to adjust your heat pump O/B wire orientation settings on your Nest Learning Thermostat. Here’s how.

If your Nest Learning Thermostat is in heating mode but is cooling your home or is heating your home in cooling mode, you may need to adjust the O/B wire orientation in Settings.

If you think you are experiencing this issue, make sure to test both your heating and cooling. If you’re in heating mode, try having the Nest Thermostat cool your home. Change to cooling mode using the heating and cooling icons in the menu, then lower the target temperature until the display turns blue. Wait a couple of minutes and check the air coming from your vents.

If your system starts blowing hot air when your Nest Thermostat is cooling (or vice versa), you’ll need to change the orientation of your heat pump:

  • Press the ring to access the Menu.
  • Turn the ring and select SETTINGS.
  • Select EQUIPMENT.
  • Select CONTINUE (TWICE).
  • Select HEAT PUMP.
  • The Nest Learning Thermostat defaults to an O orientation for heat pumps. If the O option is highlighted, select B. If the B option is highlighted, select O.
  • Test your heating and cooling once again to make sure the issue is resolved.

If this doesn’t resolve the problem, turn off the power to your heating and cooling system, then disconnect the wire in the O/B connector. Verify that the wire is straight and that there is between ⅓ and ½ inches of copper wire exposed. If not, clip and strip the wire as needed.

Plug the wire back into the Nest Thermostat and replace the display. Turn your system’s power back on and test heating and cooling again.