BoilerFaultCodesChaffoteaux 3- Fault Code
Also written as 3 — same fault.
The Chaffoteaux 3- fault code means: your boiler has failed to ignite because it cannot detect a steady flow of gas, likely due to air being trapped in the supply line.. It appears on 2 Chaffoteaux models in our database.
Technical description: red L.E.D. light on reset button - Purge the gas pipe and press RESET button
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 3- fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Chaffoteaux 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 7 July 2026