Frequent sooting (3) Emergency

Chaffoteaux Frequent sooting (3) Fault Code

Also written as FREQUENTSOOTING3 — same fault.

The Chaffoteaux Frequent sooting (3) fault code means: your boiler is not burning fuel efficiently, leading to a dangerous build-up of debris inside that prevents it from heating your home properly.. It appears on 1 Chaffoteaux model in our database.

Act immediately

Turn off your boiler and stop using gas appliances. Call a Gas Safe engineer now. This fault can be dangerous if ignored.

Technical description: Heat exchanger fins blocked.
Typical repair cost £250-450 (including labour)

Engineer required

This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.

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Chaffoteaux models that show the Frequent sooting (3) fault code

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

Source

Chaffoteaux Frequent sooting (3) fault code information on this page is sourced and cross-checked against the official Chaffoteaux service / installation manuals for each affected model.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 27 April 2026