How much does it cost to fix Saunier Duval error code Neon 4 lit?

Typical repair cost for the Saunier Duval Neon 4 lit fault is £200-400 including labour.

Neon 4 lit High

Saunier Duval Neon 4 lit Fault Code

Q: What does the Saunier Duval Neon 4 lit fault code mean?

Your boiler's control system is failing to send the necessary electrical signal to the gas valve, meaning the boiler cannot ignite to provide heating or hot water.

Also written as NEON4LIT — same fault.

The Saunier Duval Neon 4 lit fault code means: your boiler's control system is failing to send the necessary electrical signal to the gas valve, meaning the boiler cannot ignite to provide heating or hot water.. It appears on 2 Saunier Duval models in our database.

Technical description: Is Neon 4 lit? NO: Is there 230V~ between pilot multi-functional control solenoid blue and brown connections? NO: Isolate supply, test harness continuity. If satisfactory replace printed circuit board.

Typical repair cost £200-400 (including labour)

Engineer required

This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.

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Saunier Duval models that show the Neon 4 lit fault code

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

Source

Saunier Duval Neon 4 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