Viessmann Vitodens 222-F B2TA Installation And Service Instructions Manual page 141

Repair
(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
1. ■ Boiler water temperature sensor
Pull the leads from boiler water
temperature sensor A 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 on the heating
water side before replacing
the sensor.
Troubleshooting
141