BoilerFaultCodesWorcester Bosch 234 Fault Code
The Worcester Bosch 234 fault code means: your boiler has detected an electrical problem with the component that controls the gas supply, meaning it cannot safely light the burner to provide heat or hot water.. It appears on 9 Worcester Bosch models in our database.
Technical description: Gas valve electrical fault
What causes the Worcester Bosch 234 fault?
This fault occurs when the boiler's main control board detects an unexpected electrical signal or a total loss of communication with the gas valve. The most common reason is an internal electrical failure within the valve itself or a loose connection in the wiring that prevents the system from safely managing the flow of fuel. Because the boiler cannot guarantee the burner will light correctly, it shuts down as a safety precaution.
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 234 fault code
Click a model for the full fault code list and model-specific repair notes.
- 1000 Repair: £150-250
- Greenstar 2000 Repair: £180-300
- Greenstar 27CDi Repair: £180-300
- Greenstar 28CDi Repair: £180-300
- Greenstar 4000 Repair: £180-350
- Greenstar 8000 Repair: £180-300
- Greenstar 8000 Life/Style Repair: £220-380
- Greenstar 8000 Style Repair: £180-350
- Greenstar CDi Compact Repair: £150-250
Source
Worcester Bosch 234 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