Worcester Bosch Greenstar 4000 Combi fault codes

18 codes from the Worcester Bosch manual for the Greenstar 4000 Combi gas boiler. Pick one for what it means, the likely causes and where to start.

Code	What it means
1013	Max. combustion point reached (the maximum burner time is reached)
1021	Cylinder charging or hot water temperature sensor faulty
1037	Outside temp. sensor faulty - heating backup operation active
1065	System pressure sensor faulty or not connected
1068	Outside temp. sensor or lambda probe faulty
1073	Short-circuit at flow temp. sensor
1074	No signal from flow temperature sensor
1075	Heat exchanger temp sensor short circuit
1076	Heat exchanger temp sensor disconnected
2085	Internal fault
214	Fan shut down during safety time
224	Maximal flue gas thermostat or heat exchanger maximal thermostat has activated (blocking)
228	Flame signal without flame present
234	Gas valve electrical fault
235	Conflicting versions of boiler electr. and boiler identification
238	Boiler electronics faulty
242	Boiler electr. system fault
245	System fault boiler electronics / basic controller