BoilerFaultCodesWorcester Bosch F0 Fault Code
The Worcester Bosch F0 fault code means: your boiler's internal computer has encountered a critical electronic glitch that is preventing it from running safely.. It appears on 14 Worcester Bosch models in our database.
Technical description: Internal error / Sensor test failed / Recycle time error / Too many short burner starts without confirmation
What causes the Worcester Bosch F0 fault?
This fault occurs when the boiler's central control board suffers a critical electronic failure, meaning it can no longer communicate with the internal components. The most common reason is a hardware malfunction within the circuitry or an electrical surge that has damaged the delicate microprocessors. In some cases, loose or damaged wiring connections between the board and the sensors can also trigger this shutdown.
DIY fix possible
Locate the 'Reset' button on the front control panelPress and hold the button for 5 seconds, then releaseWait up to 10 minutes to see if the boiler restarts and the error clears
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 F0: no call-out fees, no surprise bills.
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Worcester Bosch models that show the F0 fault code
Click a model for the full fault code list and model-specific repair notes.
- 24/28/35 CDi MkII Repair: £150-350
- CDi Classic Repair: £120-£450
- CDi Classic Regular Repair: £200-450
- CDi Highflow Repair: £200-450
- Greenstar 12i System Repair: £250-450
- Greenstar 28CDi Repair: £150-300
- Greenstar 30CDi Classic System ErP Repair: £250-£550
- Greenstar 30i Repair: £180-450
- Greenstar CDi Compact Repair: £280-450
- Greenstar Heatslave II Repair: £150-350
- Greenstar Ri Repair: £250-500
- Greenstar Si Combi / i System Repair: £250-£550
- Hideaway 90 Repair: £120-350
- Highflow CDi Repair: £250-500
Source
Worcester Bosch F0 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 CDi Classic manual (PDF)
- Worcester Bosch CDi Classic Regular manual (PDF)
Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 7 July 2026