Smart thermostat shows E14 and cannot detect the external temperature sensor (if used with underfloor heating or special setups).

Safety warning: External sensor wiring is usually low-voltage but may be near mains. Turn off power to the thermostat before working on terminals.

• Verify sensor presence: Confirm that your installation actually uses an external floor or remote sensor and that the thermostat is configured for it in the app.
• Check wiring: Remove the thermostat from its base and inspect the external sensor wires. Ensure they are firmly clamped in the correct low-voltage sensor terminals.
• Inspect cable: Follow the sensor cable as far as accessible to check for cuts, pinches, or damage.
• Confirm sensor type: Ensure the installed sensor matches Tado’s specified NTC type and resistance. Using an incompatible sensor can cause detection errors.
• Reconfigure if unused: If no external sensor is actually installed, disable external sensor mode in the Tado app so the thermostat uses its internal sensor instead.