Thermostat shows E20 and reports sensor calibration error

Safety first: No mains work is required.

• Reset calibration: In the thermostat menu or Wiser app, look for temperature offset or calibration settings and reset them to default.
• Factory reset: Perform a full factory reset of the thermostat and reconfigure it.
• Compare with reference: Use a reliable thermometer to check actual room temperature and apply a small offset if supported.
• If E20 persists after reset: The internal calibration data area may be damaged. Replace the thermostat.