Thermostat displays E12 and may show incorrect date/time or scheduling issues

Note: This error affects scheduling and time-based functions more than basic HVAC control.

• Step 1 – Manually reset time and date: Go to the thermostat settings and re-enter the correct time, date, and time zone.
• Step 2 – Factory reset: Back up any custom schedules, then perform a factory reset from the installer or advanced settings menu.
• Step 3 – Firmware update: Connect the thermostat to Wi‑Fi and check for firmware updates. Install any available updates to correct known memory issues.
• Step 4 – Surge protection: If your home experiences frequent power issues, consider installing a surge protector on the HVAC circuit to prevent future damage.
• Step 5 – Replace thermostat if error returns: Persistent E12 after reset and update indicates internal memory failure; replace the thermostat.