28 Medium

Worcester Bosch 28 Fault Code

The Worcester Bosch 28 fault code means: your boiler is struggling to accurately measure the temperature of your hot water, which means the system may stop producing hot water or fail to regulate the temperature properly.. It appears on 3 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: DHW temperature sensor faulty
Typical repair cost £120-220 (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 28 fault code

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

Source

Worcester Bosch 28 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 7 July 2026