Viessmann Vitotwin 300-W Installation And Service Instructions For Contractors page 142

Troubleshooting
Repairs
(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
142
1. Pull the leads from boiler water tem-
perature sensor A and check the
resistance.
2. Check the sensor resistance and
compare it with the curve.
3. Replace the sensor in the case of
severe deviation.
Danger
The sensor is immersed in the
heating water (risk of scald-
ing).
Drain the boiler before replac-
ing the sensor.