High
Neon 3 on Saunier Duval Xeon 120 FF

Your boiler has detected an issue with its internal air supply system, which is preventing it from igniting or staying lit.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed

Call an engineer soon

Book a Gas Safe engineer within 24 to 48 hours. Your boiler may be unsafe or could break down completely if left.

What the manual says

Manufacturer manual

Is neon 3 lit? NO: Is there 230V~ between "N/C" on air pressure switch and N? NO: Check yellow cable between printed circuit board and air pressure switch. If satisfactory replace printed circuit board.

From this model's manual
Verified against the Saunier Duval Xeon 120 Ff installation & service manual.
Plain-English guidance below. Severity, DIY steps, costs and parts are our interpretation to help you act, not text from the manual.

Engineer required

This is a high severity fault. Stop using the boiler and call a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.

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Related fault codes

Neon 1View →Neon 2View →

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