F Emergency

Worcester Bosch F Fault Code

The Worcester Bosch F fault code means: your boiler has detected an internal control setting issue with the gas valve switch, which prevents it from operating safely.. It appears on 3 Worcester Bosch models in our database.

Act immediately

Turn off your boiler and stop using gas appliances. Call a Gas Safe engineer now. This fault can be dangerous if ignored.

Technical description: Flash 4 times per second: Gas Valvemode switch on min or max.
Typical repair cost £150-300 (including labour)

Engineer required

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

Find a Gas Safe engineer

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Worcester Bosch models that show the F fault code

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

Source

Worcester Bosch F 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 31 August 2026