High
b 24 on Ideal Imax W

Your boiler has detected that water is flowing in the wrong direction or is hotter returning from your radiators than it is leaving the boiler, likely due to a circulation problem.

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

Return temperature > Flow temperature for excessive time

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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