Chaffoteaux 5.vi Fault Code
Also written as 5VI — same fault.
The Chaffoteaux 5.vi fault code means: your boiler is failing to heat your water properly because the internal valves that control gas flow are not responding as they should.. It appears on 3 Chaffoteaux models in our database.
Technical description: Hot water does not operate over temperature range - Solenoids not operating
Engineer required
This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
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Gas Safe Register →Chaffoteaux models that show the 5.vi fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Chaffoteaux 5.vi 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