Viessmann Vitocrossal 300 Series Service Instructions Manual page 94

Troubleshooting
Corrective Action
Temperature sensors
Temperature sensors
94
(continued)
Vitocrossal 300 CU3A 26 to 199 Service
Checking the DHW / low loss header / heating circuit /
room temperature sensor
1. Pull the leads from temperature sensor.
2. Check the sensor resistance and compare it with
the curve.
3. Replace the sensor in the case of severe deviation.
Checking the boiler temperature sensor
1. Pull plug § and measure the resistance.
2. Check the sensor resistance and compare it with
the curve.
3. Replace the sensor in the case of severe deviation.
4. Release the strain relief on the sensor well and pull the
sensor out of the well and disconnect plug. Install the
new sensor in reverse order.