Repairs - Viessmann VITODENS 333 Service Instructions Manual

Troubleshooting

Repairs

Checking the outside temperature sensor (weather-compen-
sated control unit)
84
1. Pull plug X3 from the control unit.
2. Test the resistance of the outside
temperature sensor across term-
inals X3.1 and X3.2 on the pulled
plug and compare with the curve.
3. Where actual values strongly devi-
ate from the curve values, discon-
nect the wires at the sensor and
repeat test directly at the sensor.
4. Depending on the result, replace
cable or outside temperature sen-
sor.