5 flashes High

Worcester Bosch 5 flashes Fault Code

Also written as 5FLASHES — same fault.

The Worcester Bosch 5 flashes fault code means: your boiler has identified that the fan responsible for clearing exhaust fumes is not spinning at the correct speed, preventing it from starting safely.. It appears on 3 Worcester Bosch models in our database.

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: Fan speed too low. Check fan lead and connector, and fan; replace as necessary.
Typical repair cost £250-£450 (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 5 flashes fault code

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

Source

Worcester Bosch 5 flashes 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