High
311 on Worcester Bosch Greenstar CDi Compact

Your boiler's electronic control unit has identified an internal software or configuration error that has caused it to lock itself to prevent damage.

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

CUS locked

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

312View →313View →

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