Worcester Bosch 5S Fault Code
The Worcester Bosch 5S fault code means: your boiler has stopped working because it cannot confirm that the fan is blowing air through the flue correctly and safely.. It appears on 1 Worcester Bosch model in our database.
Technical description: Air pressure switch
Engineer required
This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
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Gas Safe Register →Worcester Bosch models that show the 5S fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Worcester Bosch 5S 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