High Lockout
FD231 on Worcester Bosch CDi Classic

Your boiler has lost power or experienced an electrical error while it was already trying to show a different fault code.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed

Call an engineer soon

Book a Gas Safe engineer within 24 to 48 hours. Your boiler may be unsafe or could break down completely if left.

Technical description

The power has been interrupted during a lockout

What causes this fault?

This fault occurs when the boiler loses electrical power at the exact moment it was trying to record or display a different technical error. It is usually caused by a loose connection in the internal wiring or a failing main circuit board that can no longer process electrical signals correctly. Essentially, the boiler's internal computer has crashed while trying to report a problem, leaving it in a confused state.

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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Related fault codes

EAView →F7View →E9View →

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