E16 displayed and thermostat indicates a clock or timekeeping error; schedules run at incorrect times.

Safety first: No special electrical risk for time settings; avoid opening mains-powered units unless power is off.

• Resync time: If connected to Tydom or the internet, force a time synchronization via the app or by toggling network connection.
• Manual time set: Enter the thermostat menu and manually set the correct date and time. Observe if it drifts or resets after a power cycle.
• Firmware update: Check for and install any available firmware updates that may correct RTC issues.

If E16 persists and the clock cannot keep time, the internal RTC hardware is likely faulty. Replacement of the thermostat is usually required.