Cannnot 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)

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.