Troubleshooting - Bosch HP270-2 Technical Manual

6) Troubleshooting

Code E01 – Lock Out error (reset by pressing OK for more than 3 sec)
Fault in the hot water NTC temperature sensor (in the top of the tank) (10 kΩ type)
The NTC sensor is
interrupted or in short
circuit
Refer to table with
values in Service
Manual
See spare part list
Page 41 from 56
Ensure NTC connection wire is
correctly plugged in control unit
Unplug connection and Measure the
NTC electrical resistance [R] (Ω)
[R] > 55 kΩ or < 0.68 kΩ
Yes
NTC value out of
range
Change wiring and ensure
sensor is assembled correctly
Plug NTC connection
wire and turn ON unit
Problem solved?
No
Replace control unit
6-720-821-364 SM HP270 – 250 - 200 2016/12 en
Note:
NTC top (hot water)
No
[R] = ∞ Ω
Yes
NTC interrupted
Yes
End
See spare part list
No