High
b24 on Johnson Starley Warmcair DW

Your boiler has detected that water is heating up too quickly because it isn't moving through the system fast enough.

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

ΔT flow/return > 40°C

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

b25View →b30View →E02View →

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