Checking The Boiler Water Temperature Sensor, Cylinder Temperature Sensor Or Flow Temperature Sensor Of Low Loss Header - Viessmann Vitodens 222-F Installation And Service Instructions For Contractors

Troubleshooting
Maintenance
(cont.)
Checking the boiler water temperature sensor, cylinder temperature sensor or flow temperature
sensor of low loss header
A
5
Fig. 56
20
10
8
6
4
2
1
0.8
0.6
0.4
10 30 50 70 90 110
Temperature in °C
Fig. 57 Sensor type: NTC 10 k
104
X3
Ω
1. ■ Boiler water temperature sensor
Disconnect leads from boiler water temperature
sensor and check resistance.
A
Cylinder temperature sensor
■
Pull plug from the cable harness at the control
%
unit and check resistance.
■ Flow temperature sensor
Disconnect plug "X3" at 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. 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.