107
Fig. 75
10
1
10 30 50 70 90 110
Temperature in °C
0.4
0.6
0.8
2
4
6
8
20
Resistance
in kΩ
Fig. 76
Sensor type: NTC 10 k
Ω
1.
Pull out leads at flue gas temperature sensor
A
.
2.
Check the sensor resistance and compare it to the
curve.
3.
In the event of severe deviation replace the sensor.
Fault "A3" during commissioning
During commissioning, the control unit checks whether
the flue gas temperature sensor is correctly positioned.
If the flue gas temperature sensor is not positioned
correctly, commissioning is cancelled and fault mes-
sage A3 is displayed.
1.
Check whether the flue gas temperature sensor is
correctly inserted. See previous diagram.
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.
Checking the temperature limiter
If the burner control unit cannot be reset after a fault
shutdown although the boiler water temperature is
below approx. 75 °C, check the following:
Troubleshooting
Maintenance
(cont.)
5773 238 GB
Diagnosis
