6.iv High

Chaffoteaux 6.iv Fault Code

Also written as 6IV — same fault.

The Chaffoteaux 6.iv fault code means: your boiler is failing to light the burner because it cannot detect that water is moving through the system to provide heating or hot water.. It appears on 3 Chaffoteaux models 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: No main burner - Flow switch not operating
Typical repair cost £150-250 (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 6.iv fault code

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

Source

Chaffoteaux 6.iv 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