BoilerFaultCodes
Worcester Bosch Boiler Fault Codes
4,902 fault codes across 74 Worcester Bosch boiler models — explained in plain English.
Market-leading UK boiler brand, part of the Bosch Group. Known for reliability and long warranties.
Just want the most common Worcester Bosch problems?
The top 8 faults across the whole Worcester Bosch range — causes, DIY checks, repair costs.
High-severity Worcester Bosch fault codes
A1 A7 A8 B1 C6
Your boiler has detected that there is not enough water circulating through the system, which could be due to a leak or a mechanical issue with the pump.
CDi Classic
Your boiler's hot water sensor has failed or has a broken connection, meaning you likely won't have any hot water.
CDi Classic
Your boiler has lost its connection to the external heating controls, meaning it cannot receive instructions on when to turn on or off.
CDi Classic
Your boiler's computer memory chip is loose or missing, meaning the system doesn't know which model it is and has stopped working for safety.
CDi Classic
Your boiler has stopped working because the internal fan, which safely removes waste gases, is not spinning fast enough.
CDi Classic
All models
74 Worcester Bosch boiler models
CDi Classic
CombiRegular Discontinued
Greenstar Si Combi / i System
CombiSystem Discontinued
GB162
SystemRegular Discontinued
Highflow CDi
Combi Discontinued
Greenstar Ri
Regular
Greenstar 8000 Life/Style
CombiSystemRegular
24CDi BF
Combi Discontinued
Greenstar 12Ri
Regular Discontinued
Greenstar 15sbi
Regular Discontinued
24/28CDi II RSF
Combi Discontinued
Greenstar 24i Junior
Combi Discontinued
24i RSF
Combi Discontinued
24si II
Combi Discontinued
Greenstar 25CDi
Combi Discontinued
Greenstar 25Si
Combi Discontinued
Greenstar 27CDi
Combi Discontinued
Greenstar 12i System
System Discontinued
Greenstar 25 HE Combi
Combi Discontinued
Greenstar 30HE
Combi Discontinued
Greenstar Camray Utility
RegularOil
Greenstar CDi Compact
Combi
Greenstar Heatslave II
OilCombi
Greenstar Utility 18/25
RegularOil Discontinued
WR325 RSF
Combi Discontinued
Greenstar 25HE
Combi Discontinued
Greenstar 25i (ZWB 7-25)
Combi Discontinued
1000
Combi
Greenstar 2000
Combi
Greenstar 4000
CombiSystem
Greenstar 8000
CombiSystem
Greenstar 8000 Style
Combi
Greenstar 8000 Life
CombiSystem
Greenstar i
Combi Discontinued
Greenstar Si
Combi Discontinued
Greenstar i Junior
Combi Discontinued
CDi Classic Regular
Regular Discontinued
CDi Highflow
Combi
Greenstar System
System
28i Junior
Combi Discontinued
30i Junior
Combi Discontinued
Highflow 400 CDi
Combi Discontinued
Highflow 550 CDi
Combi Discontinued
Highflow 440 CDi
Combi Discontinued
CDi
Combi Discontinued
Greenstar 28CDi
Combi Discontinued
Greenstar 35 CDi
Combi Discontinued
Greenstar 42CDi
Combi Discontinued
26 CDi Xtra
Combi Discontinued
Heatslave
CombiOil Discontinued
24 RSF
Combi Discontinued
28 RSF
Combi Discontinued
CDi RSF
Combi Discontinued
35 RSF
Combi Discontinued
28i RSF
Combi Discontinued
Junior 24i
Combi Discontinued
Junior 28i
Combi Discontinued
Hideaway
Regular Discontinued
Danesmoor
Regular
Highflow 250
Combi Discontinued
Highflow 300
Combi Discontinued
Greenstar 8000 Life System
System
Greenstar Utility
Regular Discontinued
Greenstar 30si
Combi Discontinued
Greenstar R29 40 HE
Regular Discontinued
Utility
Regular Discontinued
Ri 25 HE
Regular Discontinued
24i/28i Junior
Combi Discontinued
Greenstar 15i System
System Discontinued
R30 HE Plus
System Discontinued
537i
Combi
TA 211 E
Regular Discontinued
ZB 7 27 HE
System Discontinued
ZWB 7-25
Combi Discontinued
Worcester 25/30 HE
Combi Discontinued