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.

What the manual says

Manufacturer manual

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

From this model's manual
Verified against the Worcester Bosch Greenstar Cdi Compact installation & service manual.
Plain-English guidance below. Severity, DIY steps, costs and parts are our interpretation to help you act, not text from the manual.

Engineer required

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

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