Thermostat shows E14 and refuses to operate due to detected internal temperature sensor overheat.

Safety first: If the thermostat feels hot to the touch, switch off power at the breaker and allow it to cool before handling.

Steps to diagnose and fix:

• 1. Check installation location: Ensure the thermostat is not installed above high-load electrical devices or in a sealed cavity with no airflow.
• 2. Inspect ventilation: Verify that the thermostat's ventilation slots are not blocked by paint, wallpaper, or furniture. Clear any obstructions.
• 3. Measure ambient temperature: Use an external thermometer to confirm that the room temperature is within normal range. If the thermostat reads much higher, the internal sensor or PCB may be overheating.
• 4. Reduce load inside housing: If multiple devices are installed in the same wall box, consider relocating high-heat devices (e.g., dimmers) to a separate box.
• 5. Replace thermostat if persistent: If E14 recurs even in a cool, well-ventilated location, internal components may be failing. Replace the thermostat.

When to call a professional: For complex wall box reconfiguration or if overheating is suspected from wiring issues, consult an electrician.