High
B 29 on Keston C40

Your boiler is struggling to communicate with its internal air-moving mechanism, meaning it cannot safely start up to provide heat or hot water.

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

Incorrect signal from fan. Possible fan faulty.

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

B 28View →B 30View →

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