Thermostat shows E16 and indicates a fault with the humidity sensor (if equipped).

Safety first: Turn off power before removing the thermostat from its base.

Steps to attempt fix:

• 1. Check environment: Ensure the thermostat is not installed in a bathroom, kitchen steam zone, or other high-humidity area outside its specification.
• 2. Gently clean vents: Use a soft brush or dry compressed air to remove dust from the sensor vents. Do not use liquids or solvents.
• 3. Reboot device: Power-cycle the thermostat and check if E16 clears.

When to call a professional: Humidity sensors are integrated and not user-replaceable; persistent E16 usually requires thermostat replacement.