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 10 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.
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A cover plan would handle faults like 233: no call-out fees, no surprise bills.
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Worcester Bosch models that show the 233 fault code
Click a model for the full fault code list and model-specific repair notes.
- 24/28/35 CDi MkII Repair: £250-450
- Greenstar 1000 Repair: £250-450
- Greenstar 12i System Repair: £250-450
- Greenstar 2000 Repair: £200-400
- Greenstar 27CDi Repair: £200-400
- Greenstar 28CDi Repair: £250-450
- Greenstar 4000 Repair: £250-450
- Greenstar 8000 Life & Style Repair: £180-450
- Greenstar CDi Compact Repair: £250-450
- Greenstar Heatslave II Repair: £250-450
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.
- Worcester Bosch 24/28/35 CDi MkII manual (PDF)
- Worcester Bosch Greenstar 1000 manual (PDF)
- Worcester Bosch Greenstar 12i System manual (PDF)
Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 7 July 2026