Medium
H11 on Worcester Bosch Greenstar Ri

Your boiler is struggling to detect when you are using hot water, which may cause your water to stay cold or fail to heat up properly.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed

Book a service

This fault should be looked at by a Gas Safe engineer within the next week or two. It may get worse if left.

What the manual says

Manufacturer manual

Hot water flow sensor defect

From this model's manual
Verified against the Worcester Bosch Greenstar Ri installation & service manual, page 63.
Plain-English guidance below. Severity, DIY steps, costs and parts are our interpretation to help you act, not text from the manual.

Engineer required

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

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