Thermostat displays P012 and VOC/air quality readings are unavailable or clearly incorrect.

Safety: Avoid using aerosols, solvents, or harsh cleaners near the thermostat.

• Step 1 – Remove environmental sources: Ensure there are no strong chemical vapors (paint, cleaners, aerosols) near the thermostat. Ventilate the area.
• Step 2 – Reboot and recalibrate: Power cycle GLAS by removing it from the wall plate for 60 seconds. After reboot, allow several hours for the VOC sensor to recalibrate to the environment.
• Step 3 – Firmware update: Check for and install any firmware updates that may address sensor calibration issues.
• Step 4 – Compare with external monitor: If you have an external air quality monitor, compare readings to determine if GLAS is clearly out of range.
• Step 5 – Replace thermostat: Persistent P012 indicates a failed VOC sensor module. The sensor is integrated and not field‑replaceable; replace the GLAS thermostat.