BoilerFaultCodesWorcester Bosch 233 Fault Code
The Worcester Bosch 233 fault code means: your boiler's computer has lost the ability to identify itself and requires a professional reset or part replacement.. It appears on 8 Worcester Bosch models in our database.
Technical description: Boiler identification module or device electronics faulty
What causes the Worcester Bosch 233 fault?
This fault occurs when the boiler's main control board loses communication with a specialized memory chip that tells the unit exactly which model and power rating it is. It is typically caused by a loose connection, a power surge that has corrupted the internal data, or a hardware failure within the identification module itself.
Engineer required
This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
Find a Gas Safe engineer
Search the official register for a qualified engineer in your area.
Gas Safe Register →Worcester Bosch models that show the 233 fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Worcester Bosch 233 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