CA Medium

Worcester Bosch CA Fault Code

The Worcester Bosch CA fault code means: 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.. It appears on 5 Worcester Bosch models in our database.

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.

Technical description: Flow rate through the DHW heat exchanger too high
Typical repair cost £120-250 (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 CA fault code

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

Source

Worcester Bosch CA 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