SOOT FORMED Emergency

Chaffoteaux SOOT FORMED Fault Code

Also written as SOOTFORMED — same fault.

The Chaffoteaux SOOT FORMED fault code means: your boiler is struggling to breathe, causing a build-up of waste material that indicates it is not burning gas cleanly, which can be dangerous.. It appears on 2 Chaffoteaux models 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: ii) Primary air supply restricted, iii) Wrong injectors
Typical repair cost £150-300 (including labour)

Engineer required

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

Find a Gas Safe engineer

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Chaffoteaux models that show the SOOT FORMED fault code

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

Source

Chaffoteaux SOOT FORMED 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