Saunier Duval Neon 2 lit Fault Code
Also written as NEON2LIT — same fault.
The Saunier Duval Neon 2 lit fault code means: your boiler has stopped heating because it has detected a heat safety issue and automatically shut down to prevent damage.. It appears on 2 Saunier Duval models in our database.
Technical description: Is neon 2 lit? NO: For gravity domestic hot water systems only, check continuity of yellow link. For fully pumped systems, check overheat reset. If satisfactory replace overheat device.
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 Neon 2 lit fault code
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Source
Saunier Duval Neon 2 lit 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