High
1009 B on Worcester Bosch Greenstar 2000

Your boiler's internal pump is not communicating correctly with the main control board, meaning the system cannot circulate hot water around your home.

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

Pump communication failure or wrong pump is fitted (non-ErP).

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

F0View →C1View →

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