High
B1 on Worcester Bosch Greenstar 30si

Your boiler's internal computer is struggling to identify the specific settings it needs to operate, so it has safely shut down to prevent incorrect functioning.

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

Coding plug not detected

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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