If you need to do a Factory Reset while installing your Smart Thermostat X or Wired Smart Thermostat X for the first time, please follow these steps:
Press and hold all three buttons for 6 seconds until FR appears on the screen. Then release the buttons.
Press and hold the middle button for 6 seconds to confirm, then release the button.
The screen will blink FR during the reset, then show Hi! as it starts up.
Go to Settings > Rooms & Devices and select Add device in the tado° app.
Scan the device QR code to reinstall your device.