High
E24 on Alpha Cd25

Your boiler has detected that the water temperature entering and leaving the unit is too far apart, which usually indicates the water is not circulating correctly through the 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

Flow/Return sensor differential fault

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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