Medium
A-b2 on Worcester Bosch Greenstar 8000 Life Combi

Your boiler has detected an issue with how quickly hot water is moving through the system, which may result in inconsistent water temperatures.

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

DHW flow rate: Hot water flow rate

From this model's manual
Verified against the Worcester Bosch Greenstar 8000 Life Style installation & service manual.
Plain-English guidance below. Severity, DIY steps, costs and parts are our interpretation to help you act, not text from the manual.

What causes this fault?

This fault occurs when the boiler's internal sensors detect an unusual or inconsistent flow of water when you turn on a hot tap. It is usually caused by a physical blockage in the flow turbine, a build-up of limescale within the heat exchanger, or a communication error between the electronic sensor boards.

Engineer required

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

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