Viessmann VITODENS 300 Service Instructions Manual page 85

Repairs
(cont.)
Checking the boiler water temperature sensor, cylinder tem-
perature sensor or the flow temperature sensor of the low
loss header
1. Boiler water temperature sensor:
Pull the leads off boiler temperature
sensor A and check the resis-
tance.
Cylinder temperature sensor: Pull
plug % from the cable harness on
the control unit and check the resis-
tance.
Flow temperature sensor: Pull plug
"X3" from the control unit and check
the resistance across terminals
"X3.4" and "X3.5".
Troubleshooting
85