High
5 01 on Ariston Clas HE 24

Your boiler is failing to light the internal flame needed to produce heat and hot water, likely due to a gas supply issue, a blocked flue, or a faulty ignition sensor.

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

No fl ame detected

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 01View →5 P1View →5 P2View →

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