High
A22 on Ariston Genus 24 MFFI

Your boiler has detected an issue where it thinks water is still flowing even when it should have stopped, which is preventing it from operating correctly.

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

The flow switch does not open

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

A21View →

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