BoilerFaultCodesWorcester Bosch 263 Fault Code
The Worcester Bosch 263 fault code means: your boiler’s internal computer has encountered a software or hardware error and can no longer communicate with the rest of the system.. It appears on 8 Worcester Bosch models in our database.
Technical description: System fault boiler electronics / basic controller
What causes the Worcester Bosch 263 fault?
This fault occurs when the boiler's main control board experiences a critical internal communication failure, essentially meaning the 'brain' of the unit has become unresponsive. The most common reason is an electrical component failure on the printed circuit board or a loose connection within the internal wiring harness that prevents data from traveling between the sensors and the controller.
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 263 fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Worcester Bosch 263 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