High
2931 on Worcester Bosch Greenstar 8000 Style

Your boiler's internal computer is experiencing a critical processing error and has stopped functioning to protect itself from unpredictable 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

Illegal instruction executed by microcontroller

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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