Repairs - Viessmann Vitodens 333 Service Instructions Manual

Repairs

Checking the outside temperature sensor (weather-compen-
sated control unit)
1. Pull plug "X3" off the control unit.
2. Test the resistance of the outside
temperature sensor across term-
inals "X3.1" and "X3.2" on the dis-
connected plug and compare it 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. Subject to result, replace the lead
or the outside temperature sensor.
Troubleshooting
79