BoilerFaultCodesTechnical description
Control mode - Maintenance
What causes this fault?
This code is triggered by an internal countdown timer within the boiler's control unit, which tracks operating hours or calendar months since the last professional visit. It is not caused by a mechanical failure or a broken part, but rather a pre-set reminder to ensure the appliance remains efficient and safe. Once your Gas Safe engineer completes the maintenance work, they will reset this timer to clear the notification.
This code often appears in autumn as homeowners turn their heating back on, revealing that the twelve-month service interval has passed during the summer months.
Engineer required
This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
Find a Gas Safe engineer
Search the official register →