BoilerFaultCodesTechnical description
Appliance lockout and power failure
What causes this fault?
This fault occurs when the boiler's control system detects a complete interruption in electrical supply or a critical communication failure between internal components. It often happens because a fuse has blown on the main circuit board or because the board itself can no longer process power correctly. In some cases, loose wiring or a sudden power surge can trigger this emergency shutdown to protect the appliance from electrical damage.
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 →