BoilerFaultCodesTechnical description
The mains voltage was interrupted during an interlocking fault
What causes this fault?
This fault occurs when your boiler loses its electrical connection at the exact moment it was trying to handle a separate internal safety issue. It effectively means the boiler's computer has become confused and entered a protective shutdown because it couldn't finish its safety check. The root cause is usually a loose connection in the wiring or a failing electronic control board that can no longer process power signals correctly.
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.
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