High
353 on Worcester Bosch Greenstar 27CDi

Your boiler has detected an internal error during its automatic safety check and has locked itself down to prevent operation.

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

Test non-volatile lockout

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

354View →356View →

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