My ecobee Thermostat Won’t Turn On: Causes and Fixes


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ecobee thermostats are normally very reliable. However, as with all technologies, sometimes they decide not to play ball, even the smart ones.

I’ll cover what steps you can take if your ecobee won’t turn on. Whether you have a new thermostat or an existing ecobee that stopped working, your issue should be here. I’ll go through causes and potential fixes.

These fixes apply to the ecobee smart thermostat lineup: ecobee3 lite, the ecobee4, and the ecobee SmartThermostat. 

If the ecobee is working, but you’re not getting heat or air conditioning, visit one of these other articles:

ecobee Won’t Turn On, Not Working

If your ecobee thermostat doesn’t power on, there are several troubleshooting steps you can try.

To help narrow these choices down, I split these solutions into two categories. The first fixes apply if you have just installed a new thermostat and it won’t turn on. 

Troubleshooting guide for newly installed ecobee thermostats

If you’re having trouble getting your new thermostat to power on, try the potential solutions detailed below. 

1 – Is the ecobee Seated Correctly on the Backplate?

Often, it is simply that the Thermostat isn’t seated properly on the backplate. Make sure the connected wires on the backplate aren’t protruding and stopping the thermostat from making the correct contact. You should hear a click once the thermostat is placed correctly. 

2 – Check for Loose Wires

Except for the ecobee3 lite, ecobee thermostats require an R/Rc/Rh wire to power the unit. This power wire should be connected to the Rc terminal on the unit. If it is connected, give a gentle pull to ensure it is properly installed. The lever on the side of the terminal should also be in the down position.

3 – Is There a C Wire?

ecobee thermostats require a C-wire to power the thermostat. Check to see if you have connected a wire to the C terminal on the thermostat.

If you haven’t, check the thermostat wiring bundle for a spare wire. If you have one, this can be connected to the C terminal on the HVAC system and the corresponding C terminal on the thermostat.

In cases where you don’t have a spare wire but have wires labeled as R, G, Y, then you will require a Power Extender Kit (PEK). If you installed one of these and the thermostat doesn’t power on, see the next troubleshooting step. 

4 – Is the Power Extender Kit Installed Correctly?

The ecobee3 Lite, ecobee4, and ecobee SmartThermostat can require a PEK in certain heating systems.

If you have installed a PEK and your thermostat still doesn’t power up, the first step is to check the wiring. The wiring should be configured as follows: 

  • R Wire – RC Terminal
  • G Wire – C Terminal
  • W Wire – W1 Terminal
  • Y Wire – PEK Terminal

For the PEK to provide power to the thermostat the C-wire coming from the PEK unit must be connected to the C-terminal on the Heating Systems control board. 

5 – Check The Voltage

If you are happy that all the writing is as it should be, then there is potentially a problem with the voltage.

If you are comfortable working with a voltmeter (like this one), then you can test voltage issues by checking that the voltage between the Rc and C-Wires is 24VAC. If it’s less than that, the thermostat will not power up. 

If you have no voltage or voltage is below this level, then check the following. 

  • Some HVAC systems have a safety switch that cuts off power if the equipment cover panel is open. Ensure that the panel is closed properly. 
  • Check the fuse on the furnace control board, it is normally a 3amp or 5amp fuse. Replace the fuse if it is blown (video below)
  • Check for a short circuit on the C-wire, if there is a clicking sound from the thermostat, a C-wire short is often the cause. Try using another wire as the C-wire and see if this resolves the problem.

Note:  The ecobee SmartThermostat model will flash green on the light bar if there is 24VAC power to the thermostat. If this is flashing and the thermostat still doesn’t power on, then contact ecobee support, as there may be an issue with the unit. 

How to replace fuses and reset breakers

Troubleshooting guide for ecobee thermostats that were previously working

If your ecobee thermostat was originally working, then it stopped working all of a sudden, it usually indicates a power failure between the thermostat and your HVAC furnace.

Checking the Voltage with a voltmeter from step 5 above can help identify if this is the issue. 

Other causes and fixes that you can take to try to rectify this are detailed below: 

1 – A Blown Fuse

It could be caused by a blown fuse. Open the HVAC furnace control panel, and you should see either an orange 5amp fuse or a purple 3amp fuse. Check to make sure these haven’t blown. Replace them if they are.

You can find the one that matches your blow fuse on Amazon

2 – Tripped Circuit

Check that the circuit in your breaker box that powers your HVAC system hasn’t been tripped.

3 – Tripped Float Switch

Check your furnace’s float switch, condensation pump, and drip tray to ensure that there isn’t a blockage or an excess of water. Clearing this blockage or removing the excess water should resolve the issue. 

4 – Tripped Temperature Sensor

If the furnace overheats, it can cause the temperature sensor to trip. This can be because of the furnace running for a prolonged period, or reduced airflow that can stop the furnace from cooling effectively.

Check the air filters to ensure they aren’t clogged. If they’re covered in dust and other debris, clean the filters out. If they appear to be clean, then there could be excessive dirt on other furnace components like the heat exchanger or the condensing coil. 

If it’s a furnace issue and you don’t see any surface issues, you may want to seek the help of a heating technician to dig deeper.

ecobee Touchscreen Not Working

If you have power to the thermostat, but the touchscreen isn’t working, then there are several things you can try to resolve the issue. 

– Remove the thermostat from its wall mount and place it back in. In many, instances this is all that is needed to resolve the issue. It might’ve just been something loose. 

– Turn off the circuit breaker for the furnace and wait for 30-seconds, this will reboot the heating system and the thermostat. 

– Reset the ecobee thermostat to factory settings. This should be the last resort, as performing this action could require completely configuring all settings for the thermostat from scratch. To reset, follow these steps below. 

  1. Open the ecobee app on your smartphone and select Settings
  2. Select the Reset option
  3. You will now see 3 options, Reset Registration, Reset Schedule and Preferences, and Reset All. It is unlikely that either of the first two options will address the issue, but there is no harm in trying them first, as it will save some time in reconfiguring your thermostat. However, in most instances Reset All is the selection you will require. 
  4. The thermostat will now be reset to factory settings and hopefully, with a working touchscreen.

I know it can be super frustrating when the ecobee thermostat is not working. Hopefully, one of the above steps fixes your ecobee not powering on.

If none of the above steps worked, and your touchscreen is still unresponsive or your ecobee is not turning on still, then it is possibly a fault in the device itself. At this stage, you should contact ecobee support for further guidance.