Viessmann Vitoligno 300-P Service Instructions For Contractors page 100

Troubleshooting
Repairs
(cont.)
■ If several remote control units and
additional KM BUS users are connec-
ted, make the connections via a socket
as shown in the diagram
■ Total length of all KM BUS cables up
to 50 m
Room temperature sensor, part no. 7408 012
Connection
See chapter "Vitotrol 200" or "Vitotrol
300".
Check room temperature sensor
600
590
580
570
560
550
540
530
520
510
500
0 5 10 15 20 25 30 35 40
Room temperature in °C
Specification
Sensor type
Protection
Permiss. ambient
temperature
■ during operation 0 to + 40 °C
■ during storage
and transport
100
Pt500
IP 30
−20 to + 65 °C
1. Disconnect the wires from the sen-
sor.
2. Check the sensor resistance at ter-
minals "9" and "13b".
3. Compare the measurement with the
actual temperature displayed (for
scanning, see chapter "Tempera-
tures, boiler coding card and brief
scans").
Check the installation and, in the
case of severe deviation, replace the
sensor.