How much does it cost to fix Worcester Bosch error code HIGH SMOKE NUMBER?

Typical repair cost for the Worcester Bosch HIGH SMOKE NUMBER fault is £150-300 including labour.

HIGH SMOKE NUMBER Emergency

Worcester Bosch HIGH SMOKE NUMBER Fault Code

Q: What does the Worcester Bosch HIGH SMOKE NUMBER fault code mean?

Your boiler is burning fuel improperly, which indicates the system is producing harmful exhaust fumes and needs an urgent inspection to prevent carbon monoxide buildup.

Also written as HIGHSMOKENUMBER — same fault.

The Worcester Bosch HIGH SMOKE NUMBER fault code means: your boiler is burning fuel improperly, which indicates the system is producing harmful exhaust fumes and needs an urgent inspection to prevent carbon monoxide buildup.. It appears on 7 Worcester Bosch models in our database.

Technical description: Air intake/flue blocked; Incorrect combustion settings; Oil pressure incorrect; Incorrect components used on combustion head; Faulty nozzle

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 HIGH SMOKE NUMBER fault code

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

Source

Worcester Bosch HIGH SMOKE NUMBER 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