High
C4 273 on Worcester Bosch Junior 28i

Your boiler's fan system is reporting an internal airflow error that suggests a technical component failure or a blockage in the flue.

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 →A8View →

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