Viessmann VITODENS 222-F Service Instructions Manual page 78

Troubleshooting
Corrective Action
78
(continued)
Vitodens 222-F B2TA 19 and 35 Service
Checking the outside temperature sensor
1. Pull plug "X3" from the control unit.
2. Test the resistance of the outside temperature
sensor across terminals "X3.1" and "X3.2" on the
disconnected plug and compare it with the curve.
3. Where actual values deviate severely from the curve
values, disconnect the wires at the sensor and repeat
test on the sensor itself.
4. Depending on the result, replace the lead or the
outside temperature sensor. Sensor type: NTC 10 kΩ
Checking the outlet temperature sensor
1. Pull the leads from outlet temperature sensor A.
2. Check the sensor resistance and compare it with the
curve.
3. Replace the sensor in the case of severe deviation.
Temperature sensors
Temperature