BoilerFaultCodes 200
Boiler in heating mode
Worcester Bosch Greenstar 8000 F Fault codes & diagnostics
99 fault codes with plain-English explanations, severity ratings, DIY guidance, and repair cost estimates.
Combi Gas 2025-present
GC Numbers 47-800-5647-800-5747-800-5847-800-5941-800-4141-800-4241-800-4341-800-44
Download the Worcester Bosch Greenstar 8000 F manual
PDF
Versions & GC numbers
The fault code is already on your display
Note it down before pressing reset — resetting clears the code immediately. How to read fault codes →
Severity at a glance
Each cell = one fault code. Hover to identify. 99 Unrated
Which version do you have?
The GC number on your boiler's data badge identifies the exact appliance and production years, as recorded in the UK Product Characteristics Database.
| GC number | Appliance (register name) | Produced |
|---|---|---|
| 47-800-56 | Greenstar 8000 F GR8700iF 35 C NG | 2025–present |
| 47-800-57 | Greenstar 8000 F GR8700iF 35 C LPG | 2025–present |
| 47-800-58 | Greenstar 8000 F GR8700iF 50 C NG | 2025–present |
| 47-800-59 | Greenstar 8000 F GR8700iF 50 C LPG | 2025–present |
| 41-800-41 | Greenstar 8000 F GR8700iF 35 R NG | 2025–present |
| 41-800-42 | Greenstar 8000 F GR8700iF 35 R LPG | 2025–present |
| 41-800-43 | Greenstar 8000 F GR8700iF 50 R NG | 2025–present |
| 41-800-44 | Greenstar 8000 F GR8700iF 50 R LPG | 2025–present |
Appliance names and production years are taken from the UK Product Characteristics Database (the SAP/SEDBUK register). Where a GC number is also printed in this model's own manufacturer manual, both sources were checked to agree.
Just want the most common Worcester Bosch Greenstar 8000 F faults?
The top 6 problems in plain English — with causes, DIY checks and repair costs.
Fault codes
All 99 documented codes
Tap any card for details
201
Boiler in hot water mode
202
Boiler in anti-cycle mode
203
Boiler in standby, no heat energy demand
204
Current prim. water temp. higher than set val.
208
Pump continues to run to cool the heat exchanger
214
Fan shut down during safety time
224
Maximal flue gas thermostat or heat exchanger maximal thermostat has activated
227
No flame signal after ignition
228
Flame signal without flame present
Showing 11–20 of 99
229
Not specified in text
232
Boiler locked by external switching contact
233
Boiler identification module or device electronics faulty
234
Gas valve electrical fault
235
Conflicting versions of boiler electr. and boiler identification
237
System fault
238
Boiler electronics faulty
242
Boiler electr. system fault
244
System fault boiler electronics / basic controller
245
System fault boiler electronics / basic controller
Showing 21–30 of 99
249
System fault boiler electronics / basic controller
250
System fault boiler electronics / basic controller
251
System fault boiler electronics / basic controller
252
System fault boiler electronics / basic controller
253
System fault boiler electronics / basic controller
254
System fault boiler electronics / basic controller
257
System fault boiler electronics / basic controller
258
System fault boiler electronics / basic controller
259
System fault boiler electronics / basic controller
262
System fault boiler electronics / basic controller
Showing 31–40 of 99
263
System fault boiler electronics / basic controller
265
Heat demand lower than energy supplied
268
Relay test was activated
269
Flame monitoring
273
Operation of burner and fan interrupted
281
Pump stuck or running in air
283
Burner starting Operating message, is not a fault.
284
Opening air/gas ratio control valve/oil solenoid valves Operating message, is not a fault.
305
Boiler in hot water anti-cycle mode Operating message, is not a fault.
306
Flame signal after closing the fuel supply
Showing 41–50 of 99
357
Ventilation program Operating message, is not a fault.
358
Anti-seizing functn. active Operating message, is not a fault.
360
System fault boiler electronics / basic controller
362
Boiler identification module or boiler electronics faulty
363
System fault boiler electronics / basic controller
604
System fault burner control unit
815
Low loss header temp. sensor faulty
1010
No communication via EMS BUS connection
1013
Max. combustion point reached
1017
Water pressure too low
Showing 51–60 of 99
1018
Maintenance interval expired
1019
Incorrect pump type detected
1021
Cylinder charging or hot water temperature sensor faulty
1023
Maximum run time including standby time reached
1025
Return temp. sensor is faulty
1037
Outside temp. sensor faulty - heating back-up operation active
1065
System pressure sensor faulty or not connected
1068
Outside temp. sensor or lambda probe faulty.
1070
Maintenance is due on <dd.mm.yyyy> please call your service engineer
1071
Maintenance is now due please call your service engineer
Showing 61–70 of 99
1072
Maintenance is overdue please call your service engineer
1075
Heat exchanger temp sensor short circuit
1076
Heat exchanger temp sensor disconnected
2085
Internal fault
2908
System fault boiler electronics / basic controller
2910
Fault in flue system
2914
Boiler electr. system fault
2915
Boiler electr. system fault
2916
Boiler electr. system fault
2920
Fault in flame monitoring
Showing 71–80 of 99
2923
Boiler electr. system fault
2924
Boiler electr. system fault No feedback from the modulating/current controlled gas valve.
2925
Boiler electr. system fault Unexpected feedback from the modulating/current controlled gas valve.
2926
Boiler electr. system fault Unexpected feedback from the modulating/current controlled gas valve.
2927
Flame failed during burner operation No ionisation detected after ignition.
2928
Internal fault
2931
System fault boiler electronics / basic controller Illegal instruction.
2940
System fault burner control unit Low voltage.
2946
Incorrect code plug detected
2948
No flame signal with low output
Showing 81–90 of 99
2949
No flame signal with high output
2950
No flame signal following starting procedure
2951
Loss of flame too many times Maximum unexpected flame losses exceeded.
2952
Internal fault when testing the ionisation signal
2955
Boiler does not support the parameters set for the hydraulic configuration
2956
Hydraulic configuration at the boiler activated
2957
Boiler electr. system fault
2961
No fan signal available
2962
No fan signal available
2963
The heat exchanger sensor or both supply and heat exchanger sensors are defect
Showing 91–99 of 99
2965
Flow temperature too high
2966
Flow temperature rise in heat exchanger too rapid
2968
Refilling system pressure
2969
Maximum number of refills reached
2970
Pressure drop in heating system too rapid
2971
System pressure too low
2972
Mains voltage too low
2980
Locking fault: To unlock Hold up and down arrow keys pressed simultaneously for 3 s. (Boiler locked. Contact a qualified heating engineer)
2981
Locking fault: To unlock Hold up and down arrow keys pressed simultaneously for 3 s. (Boiler locked. Contact a qualified heating engineer)
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