Technical description
Service reminder
What causes this fault?
This code appears because the boiler's internal clock has calculated that 12 months have passed since its last professional maintenance check. It is a programmed timer meant to prompt you to book a Gas Safe engineer to keep your warranty valid and the system safe. The boiler hasn't actually broken down; it is simply a proactive reminder to ensure the internal components are cleaned and tested.
This code often appears in autumn as many homeowners have their annual service completed just before the heating season begins.
Engineer required
This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.