Viessmann Vitotwin 300-W Installation And Service Instructions For Contractors page 146

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
Checking flow temperature sensor heating circuit
BSB aJ
146
?
?
1. Pull the leads from internal appliance
temperature 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.
1. Remove plug ? from the extension
for heating circuit with mixer.