BoilerFaultCodesWorcester Bosch F0 Fault Code
The Worcester Bosch F0 fault code means: your boiler's internal computer has encountered a communication error or software glitch that is preventing it from running safely.. It appears on 39 Worcester Bosch models in our database.
Technical description: Internal error.
What causes the Worcester Bosch F0 fault?
This fault occurs when the boiler's main control centre suffers a sudden communication breakdown between its internal electronic components. It is typically caused by a component failure on the circuit board or a loose connection in the wiring harness that prevents the computer from verifying its own safety checks. Because the 'brain' of the boiler can no longer guarantee safe operation, it shuts the system down immediately.
DIY fix possible
Press and hold the reset button for five secondsWait for the boiler to complete its restart sequenceIf the code persists, turn the main power switch to the boiler off and back on again
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 F0 fault code
Click a model for the full fault code list and model-specific repair notes.
- 24 RSF Repair: £120-350
- 26 CDi Xtra Repair: £120-£350
- 30i Junior Repair: £180-450
- 35 RSF Repair: £120-£350
- 537i Repair: £200-450
- CDi Repair: £150-350
- CDi Classic Repair: £120-£450
- CDi Classic Regular Repair: £200-450
- CDi Highflow Repair: £200-450
- Danesmoor Repair: £120-£450
- Greenstar 12i System Repair: £250-450
- Greenstar 2000 Repair: £150-300
- Greenstar 25 HE Combi Repair: £250-450
- Greenstar 25HE Repair: £250-450
- Greenstar 27CDi Repair: £150-300
- Greenstar 28CDi Repair: £150-300
- Greenstar 30HE Repair: £280-450
- Greenstar 30si Repair: £200-450
- Greenstar 8000 Repair: £150-300
- Greenstar CDi Compact Repair: £280-450
- Greenstar Heatslave II Repair: £150-350
- Greenstar R29 40 HE Repair: £250-450
- Greenstar Ri Repair: £250-500
- Greenstar Si Combi / i System Repair: £250-£550
- Greenstar System Repair: £150-350
- Heatslave Repair: £120-450
- Hideaway Repair: £120-350
- Highflow 250 Repair: £150-350
- Highflow 300 Repair: £150-350
- Highflow 440 CDi Repair: £150-350
- Highflow 550 CDi Repair: £150-350
- Junior 24i Repair: £180-450
- Junior 28i Repair: £120-350
- R30 HE Plus Repair: £200-450
- Ri 25 HE Repair: £250-450
- Worcester 25/30 HE Repair: £250-450
- WR325 RSF Repair: £200-450
- ZB 7 27 HE Repair: £250-450
- ZWB 7-25 Repair: £150-350
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.
Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 27 April 2026