High
Neon 3 lit on Saunier Duval Xeon 120 FF

Your boiler is failing to confirm that the flue system is clear, which is preventing it from igniting for your safety.

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.

Technical description

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.

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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