Viessmann VITODENS 343-F WS4A Installation And Service Instructions Manual page 100

Troubleshooting
Repairs
(cont.)
100
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 on the sensor itself.
4. Depending on the result, replace
the lead or the outside temperature
sensor.