Saunier Duval 41. Fault Code
Also written as 41 — same fault.
The Saunier Duval 41. fault code means: your boiler's internal computer is experiencing a critical error and needs to be attended to by a professional to get your heating and hot water back up and running.. It appears on 2 Saunier Duval models in our database.
Technical description: There is an internal fault in the Automatic Control Module.
Engineer required
This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
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Gas Safe Register →Saunier Duval models that show the 41. fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Saunier Duval 41. fault code information on this page is sourced and cross-checked against the official Saunier Duval service / installation manuals for each affected model.
Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 27 April 2026