High
5 P1 on Ariston Clas One

Your boiler has failed to light the flame on the first attempt, which usually happens because there is an issue with the gas supply or the ignition system.

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

1st ignition attempt unsuccessful

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

5 P2View →5 P3View →501View →

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