Viessmann Vitodens 200-W Installation And Service Instructions Manual page 137

Repair
(cont.)
20
10
8
6
4
2
1
0.8
0.6
0.4
10 30 50 70 90 110
Temperature in °C
Sensor type: NTC 10 kΩ
1. ■ Boiler water temperature sen-
sors
Remove lead to boiler water tem-
perature sensor § or §A and
check the resistance.
■ Cylinder temperature sensor
Pull plug % from the cable har-
ness at the control unit and check
the resistance.
■ Flow temperature sensor
Pull plug "X3" from the control unit
and check the resistance across
terminals "X3.4" and "X3.5".
2. Check the sensor resistance and
compare the actual values with the
curve.
3. Replace the sensor in the case of
severe deviation.
Danger
The boiler water temperature
sensors are immersed in the
heating water (risk of scald-
ing).
Drain the boiler before replac-
ing the sensor.
Troubleshooting
137