Medium
CA on Worcester Bosch Greenstar 30si

Your boiler has detected that the water is flowing through your hot water system faster than it can heat up, which often points to an issue with how much water is being drawn from your taps.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed

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

Technical description

Flow rate through the DHW heat exchanger too high

Engineer required

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

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Related fault codes

C6View →A7View →

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