Checking The Boiler Water Temperature Sensor, Cylinder Temperature Sensor Or Flow Temperature Sensor Of Low Loss Header - Viessmann Vitovalor 300-P Installation And Service Instructions For Contractors

Repairs (gas condensing module)
Checking the boiler water temperature sensor, cylinder temperature sensor or flow temperature
sensor of low loss header
A
%
X3
Fig. 98
20
10
8
6
4
2
1
0.8
0.6
0.4
10 30 50 70 90 110
Temperature in °C
Fig. 99 Sensor type: NTC 10 k
(cont.)
Ω
1. ■ Boiler water temperature sensor
Pull off leads from boiler water temperature sen-
sor and check resistance.
A
■ Cylinder temperature sensor
Pull plug from the cable harness at the control
%
unit and check resistance.
■ Flow temperature sensor
Pull plug "X3" at the control unit and check resist-
ance across terminals "X3.4" and "X3.5".
2. Compare the sensor resistance with the curve.
3. In the event of severe deviation replace the sensor.
Danger
The boiler water temperature sensor is
directly immersed in the heating water (risk
of scalding).
Drain the boiler on the heating water side
before replacing the sensor.
Troubleshooting
127