Thermostat displays E11 and cannot detect an external floor sensor (for in-floor heating models).

Safety first: Turn OFF power at the breaker before accessing thermostat terminals or floor sensor wiring.

Steps to check:

• Verify sensor wiring at thermostat: Remove the thermostat and ensure the two floor sensor wires are firmly secured in the designated sensor terminals.
• Check continuity of sensor cable: With the sensor disconnected from the thermostat, use a multimeter to measure resistance across the two sensor leads. An infinite reading indicates a broken cable or open sensor.
• Inspect sensor at floor entry: If accessible, check where the sensor cable enters the floor for damage or pinching.
• Compare resistance to spec: At room temperature, the NTC sensor should read within the range specified in the Mysa manual (commonly 10k–15k ohms at 25°C). A very high or infinite reading confirms failure.

If the sensor is open or out of spec, replace the floor sensor probe. If a new sensor still triggers E11, the sensor input circuit on the thermostat is likely faulty and the thermostat should be replaced.