How much does it cost to fix Worcester Bosch error code 9U 233?

Typical repair cost for the Worcester Bosch 9U 233 fault is £150-300 including labour.

9U 233 High

Worcester Bosch 9U 233 Fault Code

Q: What does the Worcester Bosch 9U 233 fault code mean?

Your boiler's internal computer is failing to communicate with its memory chip, meaning it cannot start because it has forgotten its specific configuration settings.

Also written as 9U233 — same fault.

The Worcester Bosch 9U 233 fault code means: your boiler's internal computer is failing to communicate with its memory chip, meaning it cannot start because it has forgotten its specific configuration settings.. It appears on 12 Worcester Bosch models in our database.

Technical description: HCM (Heat Control Module) - Problem with the code plug (faulty or not connected)

Typical repair cost £150-300 (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 9U 233 fault code

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

Source

Worcester Bosch 9U 233 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