Worcester Bosch CDI Highflow Combi Boiler Error Codes

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

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