High
C4 273 on Worcester Bosch Heatslave

Your boiler's internal computer has noticed the air fan was spinning when it shouldn't have been, causing the system to stop for safety.

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

Airflow present during last 24 hour

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

C6View →A1View →

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