How much does it cost to fix Worcester Bosch error code Pulsation on start?

Typical repair cost for the Worcester Bosch Pulsation on start fault is £150-350 including labour.

Pulsation on start Emergency

Worcester Bosch Pulsation on start Fault Code

Q: What does the Worcester Bosch Pulsation on start fault code mean?

Your boiler is struggling to ignite smoothly because the air and fuel mixture is incorrect or there is a blockage in the flue, causing it to shudder when it starts up.

Also written as PULSATIONONSTART — same fault.

The Worcester Bosch Pulsation on start fault code means: your boiler is struggling to ignite smoothly because the air and fuel mixture is incorrect or there is a blockage in the flue, causing it to shudder when it starts up.. It appears on 7 Worcester Bosch models in our database.

Technical description: CF - Flue draught incorrect; Combustion settings incorrect; Faulty nozzle

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 Pulsation on start fault code

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

Source

Worcester Bosch Pulsation on start 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