Worcester Bosch CDI Highflow Combi Boiler Error Codes Leave a Comment / Boiler Fault Codes, Worcester Bosch Boilers / By Emergency Plumbers / May 3, 2015 May 3, 2020 / Boiler Error Codes, Boiler Fault Codes, Combi Boiler, Domestic Gas Boiler, Worcester Bosch, Worcester Bosch CDI Highflow Worcester Bosch CDI Highflow Combi Boiler Error Codes Fault Description System Behaviour A1 Pump dry run detection or pump is running in air the system pressure needs checking A5 Tank negative thermistor coefficient (NTC) defect A7 Domestic hot water (DHW) negative thermistor coefficient (NTC) defect A8 Energy Management System (EMS) communication error B1 Code plug not detected B2, B3, B4, B5, B6 Data error B7 Burner control error C6 Fan defect D3 External temperature limiter D5 Condensate pump failure D6 Internal heat bank overflow EA Flame not detected E2 Primary negative thermistor coefficient (NTC) defect E9 Safety temperature limiter in central heating (CH) flow stat tripped F0 Internal error F1 ROM fault F7 Flame detected after appliance has been shut off FA Flame detected after gas shut off FD Reset button pressed – try pressing the reset button again
