High
B1 on Worcester Bosch Greenstar Utility 18/25

Your boiler has detected a poor connection within its internal wiring, which is preventing it from communicating properly and stopping it from operating.

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

Dirty electrical connection

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

B2View →

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