Checking The Flue Gas Temperature Sensor - Viessmann VITODENS 200-W Installation And Service Instructions Manual

Troubleshooting
Maintenance
(cont.)

Checking the flue gas temperature sensor

The flue gas temperature sensor locks out the boiler
when the permissible flue gas temperature is excee-
ded. Reset the interlock after the flue system has
cooled down by pressing reset button R.
A
Fig.55
20
10
8
6
4
2
1
0.8
0.6
0.4
10 30 50 70 90 110
Temperature in °C
Fig. 56 Sensor type: NTC 10 k
Fault during commissioning (fault A3)
During commissioning, the control unit checks correct
placement of the flue gas temperature sensor. If com-
missioning is terminated and fault message A3 is dis-
played:
1. Check whether the flue gas temperature sensor is
correctly inserted. See previous diagram.
94
Ω
1. Pull leads from flue gas temperature sensor
2. Check the sensor resistance and compare it with
the curve.
3. In the event of severe deviation replace the sensor.
2. If necessary, correct the position of the flue gas
temperature sensor or replace faulty flue gas tem-
perature sensor.
3. Press reset button R and repeat commissioning.
The check is repeated until it is completed success-
fully.
.
A