Medium
C4 273 on Worcester Bosch Greenstar CDi Compact

Your boiler has detected that the internal exhaust fan has been running non-stop for a full day, which can lead to parts wearing out or overheating.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed

Book a service

This fault should be looked at by a Gas Safe engineer within the next week or two. It may get worse if left.

Technical description

Airflow present during last 24 hours Fan has been running continuously during the past 24 hours.

Engineer required

This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.

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Related fault codes

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