Error Code F1

Factory reset completed successfully.

? What Causes This

Factory resetting of room thermostat was initiated due to misconfiguration or unknown issues.

✓ How to Fix It

Perform factory reset. - Turn the knob to select F 1 - Hold and press the knob to enter Factory Reset function. - Confirm settings and revert values to default.

Source: page 18 of the official manual

From the manual

This error code appears in:

Worcester Greenstar Comfort II RF