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Why isn't my cooling turning on?

If you’ve installed the Sensi thermostat and now find that your cooling does not turn on, proceed through the following steps until the issue is resolved.

Make sure your HVAC equipment power switch is turned on.

Most cooling equipment has a power switch, on or near the furnace or air handler that looks like a light switch. Make sure it is turned on.


Make sure the furnace door or air handler panel is in proper position.

A loose or improperly installed blower compartment door or furnace panel can keep the equipment from operating. Make sure it’s squarely in place so it will engage the safety switch inside the cabinet.

air handler

Reset your breaker.

At the main home electrical panel, turn the HVAC equipment breaker off, then turn it back on to reset the breaker.

breaker box

Test Operation

If your cooling system still does not turn on, follow the steps below to determine if the issue is related to the thermostat.

  1. Working directly on the thermostat – not through the Sensi app — set the thermostat to the Cool Mode.
  2. Raise the set point a few degrees above the room temperature.
  3. After 10 seconds, lower the set point below the room temperature by a few degrees.
  4. The thermostat should make a soft clicking sound and “Cooling” should appear on the screen near the “Set To” temperature - indicating that your thermostat is operating properly, even if the cooling does not come on. If this happens, skip the thermostat reset detailed below in step 5.

Note: If the set point is flashing on the screen there will be a maximum 5 minute delay before the thermostat clicks.

  1. If the thermostat does NOT click then you should reset the thermostat.
    • Slightly pull on both sides of the thermostat to remove the face plate from the wall.
    • Remove the two AA batteries and press the Menu button so the screen goes blank.
    • Reinsert the batteries and place the face plate back on the wall. You should hear the face plate snap in place on the sub-base connected to the wall.
    • After one minute, the thermostat should reset.
    • Repeat steps 1-4 above.
  2. If the thermostat still does NOT click and “Cooling” does not appear on the screen, replace the thermostat.

Tighten the wire connections.

  1. Pull the thermostat off the sub-base and check to make sure the wires are firmly connected to the thermostat terminals.
  2. If not, reattach or tighten them with a small screwdriver and reattach the thermostat to the sub-base.
  3. Be sure that the thermostat fits securely to the sub-base. If thermostat wiring protrudes too far past the sub-base, or if you did not use the wall screws that were provided, this can prevent your system from turning on.

Check your wiring.

If your cooling system still does not turn on, confirm that you labeled and installed your wires properly.

Did you take a picture of your old thermostat’s wiring? Make sure that you input the correct terminal labels to the wire picker when you installed your thermostat.

terminal outputs

Check your configuration

When completing the installation and connection path within the Sensi app, your thermostat will be configured automatically based on the wiring that you entered. However, if you do not complete the connection process right away, or if your thermostat is wired incorrectly, it may need to be reconfigured to reflect your system type.

  1. On the thermostat, press the Menu button.
  2. Press “Next” two times until you reach “Setup Outdoor.”
  3. Outdoor settings: If you have a heat pump, this should be set to “HP1.” If you have a conventional air conditioning unit, this should read “AC1.” If you have more than one stage of cooling, change this to “HP2” or “AC2” to represent this.
  4. Press “Next” one time to reach “Setup Indoor.”
  5. Indoor settings: If you have a gas furnace, oil burner, or boiler system, this should be set to “GA1” which represents a single stage gas heating system. If you have an electric furnace, this should be set to “EL1.” If you have more than one stage, change this to “GA2” or “EL2” to represent this.
  6. Once you’ve selected the choice that best describes your equipment, press “Exit.”

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