Emergency
A20 on Ariston Genus 24 MFFI

Your boiler has detected a flame inside the combustion chamber before it actually turned on the gas supply, implying a potential sensor or ignition system error.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed

Act immediately

Turn off your boiler and stop using gas appliances. Call a Gas Safe engineer now. This fault can be dangerous if ignored.

Technical description

The flame was detected before the gas valve opened

Engineer required

This is a emergency 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

A21View →A22View →

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