High
FAIL POINT B on Worcester Bosch Greenstar 25Si

Your boiler has suffered an internal electrical failure that is preventing it from starting up or operating safely.

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

Fuse F2 blown or transformer resistance above 100 ohms. Possible control board damage (Green diode).

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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