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

Typical repair cost for the Saunier Duval Neon 4 fault is £200-350 including labour.

Neon 4 High

Saunier Duval Neon 4 Fault Code

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

Your boiler has stopped working because the main control panel is failing to send electrical power to the internal gas valve to start the heating process.

Also written as NEON4 — same fault.

The Saunier Duval Neon 4 fault code means: your boiler has stopped working because the main control panel is failing to send electrical power to the internal gas valve to start the heating process.. 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 £200-350 (including labour)

Engineer required

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

Find a Gas Safe engineer

Search the official register for a qualified engineer in your area.

Gas Safe Register →

Saunier Duval models that show the Neon 4 fault code

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

Source

Saunier Duval Neon 4 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