Bosch GWI-N Series Training And Service Information page 58

8.2) Problems with Error Codes
A0
Fault in both inlet and outlet NTC sensor
Component Characteristic: NTC temperature sensor (10 kΩ type)
Lock Out Error
The Inlet / Outlet NTC
sensor is interrupted
or in short circuit
Refer to table with
values in Service
Manual
See spare part list
See spare part list
Page 58 from 76
Burner shutdown and manual reset necessary
Ensure NTC wire is
attached in NTC sensor
Unplug Wires and measure
the NTC electrical
resistance [R] (Ω)
[R] > 30 kΩ or < 0.5 kΩ
Yes
NTC values out of
range
Replace NTC
Plug NTC connection
wire and turn ON unit
Problem solved?
No
Change wiring
Problem solved?
No
Replace control unit
6 720 814 719 SM FP_Australia 2017/04 EN
ATTENTION:
Red wires – outlet NTC
Blue wires – inlet NTC
No
[R] = ∞ Ω
Yes
NTC interrupted
Yes
End
Yes
No