Cannot Connect Sensi to HomeKit

HomeKit Compatibility

If you’re unable to pair your thermostat to HomeKit, make sure your Sensi is compatible.

• A “C” (common) wire is required for HomeKit compatibility
  • What is a C wire or common wire?
• Sensi models that work with HomeKit:
  • Sensi Touch smart thermostat (ST75 or 1F95U-42WF series)
  • Sensi smart thermostat (ST55 or 1F87U-42WF series*)

*Not all Sensi smart thermostats are compatible with Apple HomeKit. To determine if your model is compatible, press menu then mode, while the thermostat is on the wall. If your thermostat displays 33, it is not compatible with Apple HomeKit.

 

HomeKit Troubleshooting

If your Sensi is compatible with HomeKit, but you are still receiving the “Couldn’t add Sensi” error, there is typically a sentence below the error, and it may help you narrow in on what needs to be fixed. Below are additional troubleshooting suggestions.

•  Make sure the setup code that you are scanning or entering is correct.
  • Where do I find my HomeKit Code? 
    
    
    

• Make sure you’re logged into your iCloud account on your iPhone.
• Make sure that Home Data is On in iCloud settings.
• Make sure that Keychain is On.
• Check and make sure your iCloud storage isn’t full. This may affect your ability to save home data.
• Make sure your phone’s iOS is updated.
• Power cycle your iPhone.
• Reset the thermostat and try setup again.

 

Incompatible router

If you get an error message about an incompatible router, it means your iPhone is currently connected to a 5GHz Wi-Fi network. Sensi is only compatible with 2.4GHz networks.

• Go into your phone’s Wi-Fi settings.
• “Forget” your 5GHz home Wi-Fi network. (You can reconnect again after Sensi setup is complete.)
• Connect your phone to your 2.4GHz home Wi-Fi network.
• Retry setup again.

 

General Troubleshooting

• Make sure your router is configured per our specifications: Advanced router troubleshooting.
• Check the voltage of your common wire with a voltmeter. Set your voltmeter to AC and measure the voltage between RH (or RC) and C at the thermostat to ensure that you have between 20-30VAC at the thermostat.