Viessmann Vitodens 200-W Installation Instructions Manual page 138

Troubleshooting
Maintenance
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
138
(cont.)
1. ■ Boiler water temperature sensor
1
Pull the leads from boiler water
temperature sensor §A and
check the resistance.
■ Boiler water temperature sensor
2
Pull the leads from boiler water
temperature sensor §B 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 it with the curve.
3. Replace the sensor in the case of
severe deviation.
Danger
The boiler water temperature
sensor is immersed in the
heating water (risk of scald-
ing).
Drain the boiler before replac-
ing the sensor.