High
374 8C on Worcester Bosch Greenstar CDi Compact

Your boiler has detected repeated issues with maintaining its flame during operation, so it has locked itself for safety to ensure it does not attempt to fire incorrectly.

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

Super-Lock caused by too frequent ionisation loss during burning

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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