Viessmann VITOLIGNO 300-P Service Instructions Manual page 100

Troubleshooting
Repairs
(cont.)
Flame temperature sensor
Checking the flame temperature sensor
300
250
200
150
100
50
0
0 2 4
Voltage in mV
Curve for thermocouple NiCr / Ni (type
K) at a comparison temperature of 0 °C
1. Pull off LV plug X17/aL and measure
thermoelectric power. For this, only
use a suitable measuring device for
thermocouple type K.
Specification
Sensor type
Permissible ambient temperature during
operation, storage and transport
■ Silicone equalisation line
■ Measuring insert (tip of probe)
100
6 8 10 12
2. Check insulating resistance: Thermo-
couple against casing at room tem-
perature > 200 MΩ.
3. Check the measuring insert (tip of the
measuring probe) for damage.
Note
The tip of the measuring probe must
not be bent.
4. Check the silicone equalisation line
for damage.
Viessmann insulated thermocouple
NiCr-Ni, type K
− 50 to + 180 °C
− 200 to + 1200 °C