Viessmann VITOLIGNO 300-P Service Instructions Manual page 99

Repairs
(cont.)
Checking the sensor
740
720
700
680
660
640
620
600
580
560
540
0 20 40
Flow temperature or
return temperature in ºC
Specification
Sensor type
IP rating
Permiss. ambient
temperature
■ During operation 0 to + 100 °C
■ During storage
and transport
60 80 100
Viessmann Ni500
IP 32
− 20 to + 70 °C
1. Pull plug ?.
2. Check the sensor resistance at the
plug.
3. Compare the measurement with the
actual temperature (for scanning, see
chapter "Temperatures, boiler coding
card and brief scans").
In the case of severe deviation, check
the installation and replace the sen-
sor if required.
Troubleshooting
99