Thermostat shows E19 and indicates an internal clock or timekeeping error; schedules may not run correctly.

Safety first: No high‑voltage work is required.

• Step 1 – Manually set time and date: In the thermostat settings, set the correct time, date, and time zone. Save and observe if the time drifts or resets.
• Step 2 – Enable network time sync: Ensure the thermostat is connected to Wi‑Fi and that automatic time synchronization is enabled in settings.
• Step 3 – Firmware update: Update the thermostat firmware via the Geo app to correct any known RTC bugs.
• Step 4 – Factory reset: If E19 persists, perform a factory reset and reconfigure the device, then recheck timekeeping over 24–48 hours.
• Step 5 – Replace thermostat: If the clock continues to lose time or reset and E19 remains, the RTC hardware or backup power is defective. Replace the thermostat head unit.