How much does it cost to fix Worcester Bosch error code 349 / EF?

Typical repair cost for the Worcester Bosch 349 / EF fault is £150-350 including labour.

349 / EF High

Worcester Bosch 349 / EF Fault Code

Q: What does the Worcester Bosch 349 / EF fault code mean?

Your boiler has detected that it is heating up or cooling down much faster than expected while running at its lowest setting, which typically indicates a blockage or a failure in how water is flowing through the system.

Also written as 349EF — same fault.

The Worcester Bosch 349 / EF fault code means: your boiler has detected that it is heating up or cooling down much faster than expected while running at its lowest setting, which typically indicates a blockage or a failure in how water is flowing through the system.. It appears on 2 Worcester Bosch models in our database.

Technical description: CH: Boil Detect, large delta T despite minimum burner load

Typical repair cost £150-350 (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 349 / EF fault code

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

Source

Worcester Bosch 349 / EF 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