Viessmann VITODENS 200-W Installation And Service Instructions Manual page 112

Troubleshooting
Repairs
(cont.)
2. Measure the sensor resistance across "X3.1" and
"X3.2". Compare with the curve in the following
table.
If the results are very different from the curve, dis-
connect the wires from the sensor. Repeat the test
directly on the sensor.
Depending on the result, replace the lead or the
outside temperature sensor.
Flue gas temperature sensor
1. Disconnect the leads from flue gas temperature
sensor .
B
Flue gas temperature sensor
■
Boiler water temperature sensor
■
Cylinder temperature sensor
■
Flow temperature sensor, low loss header
■
20
10
8
6
4
2
1
0.8
0.6
0.4
10 30 50 70 90 110
Temperature in °C
Sensor type: NTC 10 k
Ω
Fault during commissioning (fault A3)
During commissioning, the control unit checks correct
placement of the flue gas temperature sensor. If fault
message A3 is displayed:
1. Check whether the flue gas temperature sensor is
correctly inserted. See previous diagram.
2. Correct the position of the flue gas temperature
sensor if required.
112
2. Check the sensor resistance. Compare with the
curve in the following table.
In the event of severe deviation replace the sensor.
3. If the permissible flue gas temperature has been
exceeded, the flue gas temperature sensor locks
out the appliance. Cancel the interlock after the
flue system has cooled down by pressing reset
button R.
Outside temperature sensor (hardwired)
■
200
100
80
60
40
20
10
8
6
-20 -10 0 10 20
Temperature in °C
Sensor type: NTC 10 k
Ω
3. Switch the ON/OFF switch OFF.
4. Switch the ON/OFF switch ON again.
Re-start the commissioning assistant.
30