3 06 High

Chaffoteaux 3 06 Fault Code

Also written as 306 — same fault.

The Chaffoteaux 3 06 fault code means: your boiler's main control unit has identified an internal software or hardware failure, meaning it has safely shut down to prevent further damage.. It appears on 1 Chaffoteaux model in our database.

Call an engineer soon

Book a Gas Safe engineer within 24 to 48 hours. Your boiler may be unsafe or could break down completely if left.

Technical description: Erreur sur la carte principale
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 3 06 fault code

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

Source

Chaffoteaux 3 06 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