H09 High

Worcester Bosch H09 Fault Code

The Worcester Bosch H09 fault code means: your boiler's internal water pump is not sending signals to the control unit, which means the system cannot safely circulate heated water to your radiators or taps.. It appears on 2 Worcester Bosch models in our database.

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: Communications to the pump has failed. The feedback signal has been lost, possible causes are electrical connections loose or disconnected, pump has been replaced with an incorrect type.
Typical repair cost £180-350 (including labour)

Engineer required

This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.

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Worcester Bosch models that show the H09 fault code

Click a model for the full fault code list and model-specific repair notes.

Source

Worcester Bosch H09 fault code information on this page is sourced and cross-checked against the official Worcester Bosch service / installation manuals for each affected model.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 27 April 2026