Sensi Thermostat Not Cooling? Do This!

Sensi Thermostat Not Cooling

It can very uncomfortable to discover that your Sensi thermostat is not cooling especially on a hot summer day.

Why is Sensi Thermostat Not Cooling?

1. Your Sensi thermostat maybe experiencing a software glitch

Your Sensi thermostat maybe experiencing a software error and needs to be restarted to resume normal operations.

The software error may hinder it from sensing the temperature change request.

A restart will activate the software and clear any errors.


You need to test and reset the thermostat operation to be sure that it is merely a software glitch.

  1. If the thermostat was already in Cool Mode option, press Mode Off option.

On the Sensi app, make sure the background screen turns gray.

Make sure the word “Cooling” is not displayed on Sensi smart thermostat the thermostat:

Verify that the touchscreen turns gray on a Sensi Touch smart thermostat:

Confirm that the room temperature number is not blue on your Sensi Touch 2 smart thermostat.

Check that the word “ON” is not displayed in your Sensi Lite smart thermostat.

  1. Change the thermostat back to Cool Mode.
  2. Decrease the set point a few degrees above the room temperature.
  3. Depending your thermostat model you will either hear a click and see the cooling words on the screen or notice a change in app and thermostat screen or a click

Within a few seconds, the Sensi Smart Thermostat should produce a soft clicking sound and “Cooling” should appear on the screen near the set temperature, indicating that your thermostat is turning on your system.

Sensi Touch & Touch 2 smart thermostats and the Sensi app screen should both turn blue and you will hear a click to indicate that the thermostat is turning on your cooling system.

If you don’t hear a click, reset the thermostat and repeat this process explained here again.

  1. If there is cold air flowing out of the vents, allow your system to run and cool the room.
  2. If there is no hot air coming out of the vents, continue troubleshooting.
  3. Your Sensi Lite and Sensi smart thermostat has a low battery.

Sensi Lite or Sensi smart thermostats excluding the Sensi Touch and Touch 2 touchscreen models, have batteries in the back of your thermostat

If these batteries are low, the Sensi may not be able to turn on your system.


You need to replace the two AA alkaline batteries in the back part of your thermostat.

To replace the batteries on the Sensi smart thermostat do the following steps.

  1. Tug the face plate to detach it from the sub-base by grabbing the face plate with both hands and pulling it straight towards you.
  2. Remove the 2 AA Alkaline batteries from the face plate.
  3. Let the front display to go blank.
  4. Put in two fresh AA Alkaline batteries, and push the face place back onto the sub-base.
  5. When the face plate is pushed on securely, you will hear a snap.
  6. Wait for between one to five minutes for the thermostat to automatically reconnect to Wi-Fi.

2. Your Sensi thermostat is no longer powered on

The reason why your Sensi thermostat is not cooling the room is because it has run out of power


Ensure that your HVAC system has power.

Check power.

3. Your Sensi thermostat has experienced a Power surge

If there was a power outage recently, the electric energy could cause a power surge especially if the Sensi thermostat had not been powered off. Power surge could causes fluctuations and unsteady energy current in your electronic smart device.


Make sure you power off all electronic and smart devices during a power outage.

Allow a few minutes to pass and then let the Sensi thermostat and all your other electronic devices to come on.

You can then reset the thermostat and try testing the thermostat using the steps above.

4. Your Sensi Thermostat is switched off

Most HVAC systems including your Sensi thermostat have a power switch, on or near the furnace or air handler that looks like a light switch.


Make sure the HVAC equipment power switch for your Sensi thermostat is turned on

5. Your Sensi thermostat has a system error code

Newer HVAC systems usually have some type of light that will turn on or blink to indicate a problem with the system. It is located inside your furnace/air handler, near the control board. The blinking light code is unique to each HVAC manufacturer so if you see a blinking light, refer to your HVAC manual to diagnose the code.


Check for a system error code

6. You Sensi thermostat has loose inappropriately placed air handler or furnace door.

A loose or wrongly installed blower compartment door or furnace panel can keep the equipment from operating.


Make sure the furnace door or air handler panel is in it’s proper position

Make sure its squarely in place so it will engage the safety switch inside the cabinet.

The diagram below illustrated in this diagram

air handler

7. Your Sensi thermostat has an overloaded circuit

If your Sensi thermostat is not cooling at its expected pace, then you might be dealing with an overloaded circuit.


Reset breaker

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

If you know that your circuit is overloaded, if you are able to, immediately shift the Sensi thermostat and any other devices that were plugged into the overloaded circuit to a different general-purpose circuit.

To shift your Sensi thermostat and other devices to a different circuit, try not to use an extension cord as they are meant for short-term use.

Once the overloaded circuit has no devices connected to it, flip the circuit breaker back on or replace the fuse and turn everything back on.

This could be all that was needed for the circuit to be fixed, but it may not be a long-term solution.

It is safe to reset a breaker only if it has been established that the circuit was overloaded.

Frequently resetting a breaker could result in an arc flash or a fire.

If the cause of the circuit overload is due to a short-circuit or a ground fault, a qualified electrician must be alerted to investigate the problem.

8. Your Sensi thermostat has a clogged, frozen and/or damp Sensi thermostat components

If you have a clogged condensation drain, clogged air filter, frozen pipes (outside) or any thermostat component that is not working, the cooling may not come on.


Check your air filter and other components

Make sure to change your air filter regularly for optimal performance for your thermostat.

9. You have no voltage at in your Sensi thermostat

Voltage, also referred to as electric pressure, electric tension, or (electric) potential difference, is the difference in electric potential between two points.

It is the pressure that forces current through the electrical supply chain. Electrical current computes how many electrons flow through a specific part of the supply chain in a given amount of time.

Voltage merges with current to define how much power flows through the network.

There might be no voltage at your thermostat thus inhibiting the cooling functions.


Check voltage

With a voltmeter, check to ensure there is voltage at the thermostat.

  • Set your voltmeter to VAC and measure the voltage between available wire terminals.
  • Place one test probe on the exposed copper wire of RH (or RC), which is the power wire, and G (fan). Do the same for RH (or RC) and Y (first stage cooling for an air conditioner).
  • Record the voltage readings. If you have less than 20 VAC, the thermostat will not be able to turn on your system.

10. Wrong wiring and HVAC settings

Remember that a conventional A/C unit only provides cooling. While a heat pump is also an outdoor compressor, it provides both cooling and heating.

If your outdoor compressor runs in the fall/winter, you may have a heat pump.

If your only heat source comes from an indoor furnace or boiler system, or if you do not have heat, then you have a conventional A/C unit.

If you’re unsure of your system type, you may need to reference the model number of your outdoor compressor, and/or contact the manufacturer of your outdoor unit.

Here are examples of wire labels

  1. Conventional – R, Y, G, W, W2, Y2, C
  2. Heat Pump – R, Y, O B, W, Aux, E, C

Make sure to check your original thermostat. If it has two sets of labels, choose the inside or outside set of labels based on whether you have a conventional or heat pump system.


After confirming your system type, use the Sensi app to walk through the installation steps and choose the correct wiring labels. Make sure to take a picture of your wiring before uninstalling the original thermostat.

If you just installed your Sensi thermostat, you may need to double check that everything was installed correctly.

Did your old thermostat have two sets of terminal labels?

Be sure you entered the correct terminals that correspond to your system type (Conventional or Heat Pump) in the wire picker when you installed Sensi.

To double-check your wiring, go back through the wire picker in the Sensi app installation path and refer to the picture you took before you uninstalled your original thermostat to be sure you used the correct set of wire labels.

  1. Open the Sensi app.
  2. Tap on the + sign for additional information.
  3. Choose your Sensi product.
  4. Click on New Installation.
  5. Select Not Mounted.
  6. Tap Next five times to get to the wire picker to re-enter your original labels.

For wiring terminal designation information, refer to the wiring diagrams on your Sensi model’s Install Guide.

Note that A C wire is required for the following Sensi models:

  1. Sensi Touch smart thermostat
  2. Sensi Touch 2 smart thermostat
  3. Sensi smart thermostat – heat-only, cool-only, and heat pump systems only
  4. Sensi Lite smart thermostat – heat-only, cool-only, and heat pump systems only

Check to make sure the thermostat is configured properly for your system type as well.

Other Fixes

Reinstall original thermostat

If you still have your original thermostat (or a spare thermostat), uninstall Sensi and swap it with the other thermostat. Refer to that thermostat’s installation guide for instructions on how to move the wires and install. This is a good test to see if the problem is with the system or the Sensi.

If your Sensi thermostat is still not working contact a HVAC professional to troubleshoot your equipment.

Now you know how to fix a Sensi thermostat or AC that is not cooling.

Brady Klinger-Meyers is an experienced writer and marketer with who currently writes for Robodens as well as other popular sites like MakeUseOf and Techzillo. At Robodens, he focuses on general smart home advice with his interest being accessories and gadgets. Read our Editorial Guidelines and Fact Checking process.


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