273 C4 Medium

Worcester Bosch 273 C4 Fault Code

Also written as 273C4 — same fault.

The Worcester Bosch 273 C4 fault code means: your boiler has detected that the internal fan is running when it should be idle, often caused by a communication error or a sensor glitch.. It appears on 3 Worcester Bosch models in our database.

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
Typical repair cost £150-250 (including labour)

Engineer required

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

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Worcester Bosch models that show the 273 C4 fault code

Click a model for the full fault code list and model-specific repair notes.

Source

Worcester Bosch 273 C4 fault code information on this page is sourced and cross-checked against the official Worcester Bosch service / installation manuals for each affected model.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 27 April 2026