BoilerFaultCodesChaffoteaux 5.v Fault Code
Also written as 5V — same fault.
The Chaffoteaux 5.v fault code means: your boiler is struggling to control the temperature of your hot water because a safety sensor has become inaccurate.. It appears on 2 Chaffoteaux models in our database.
Technical description: Hot water does not operate over temperature range - Hot water limit stat out of calibration
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 5.v fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Chaffoteaux 5.v 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