This is a scheduled service reminder notification showing that your boiler is due for its routine professional maintenance check.

Diagnostics code: Setting the maintenance interval (operating hours)

What causes this fault?

This code appears because your Gas Safe engineer previously programmed a countdown timer or a set number of operating hours into the boiler's control system. It is physically triggered once that internal clock reaches zero, acting as a digital nudge to ensure the appliance is inspected for safety. Unlike a mechanical failure, this is a proactive alert designed to keep the boiler running efficiently through routine maintenance.