BoilerFaultCodesTechnical description
Appliance lockout and power failure
What causes this fault?
This fault occurs when the boiler's main control board loses its electrical connection or suffers a complete internal failure. It is often caused by a blown fuse, loose wiring, or a power surge that has damaged the electronic components. Without a stable power signal, the boiler's computer cannot manage the safety checks and must shut down for security.
Engineer required
This is a high severity fault. Stop using the boiler and call a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
Find a Gas Safe engineer
Search the official register →