125
5693 982 - 04
Vitotronic 300, GW2B Installation and Service
Sensors
(continued)
Components
Viessmann NTC 10 k
Ω
1. Pull
plug
!
.
2. Check the sensor resistance across plug terminals
“1” and “2” and compare with the curve.
3. If the results are very different from the curve,
disconnect the wires from the sensor and repeat the
test on the sensor.
4. Depending on the result, replace the lead or the
outside temperature sensor.
Outside temperature sensor
When an entered limit in the Vitotronic 300 is reached
(see coding address “1F” in “Boiler”) group, a service
display appears.
1. Disconnect
plug
aG
.
2. Check the sensor resistance and compare it with the
curve.
3. In the case of severe deviation, check the installation
and replace the sensor if required.
Flue gas temperature sensor
Viessmann NTC 20 k
Ω
(orange identification)
Resistance in k ohms
Temperature
Temperature
Resistance in k ohms
