High
40 ●, 50 ●, red ● on Ariston Clas One

Your boiler is struggling to pump water around your heating system, usually because there is not enough water in the pipes or a blockage is preventing the flow.

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

Insufficient circulation

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

1P1View →1P2View →1P3View →

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