Checking The Temperature Limiter - Viessmann Vitodens 222-F Installation And Service Instructions Manual

Troubleshooting
Maintenance
(cont.)
Fig. 61
20
10
8
6
4
2
1
0.8
0.6
0.4
10 30 50 70 90 110
Temperature in °C
Fig. 62 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 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.

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:
100
Ω
1. Disconnect leads from flue gas temperature sensor
.
A
2. Check sensor resistance and compare it to the
curve.
3. In the event of severe deviation replace the sensor.
3. Switch the ON/OFF switch OFF.
4. Switch the ON/OFF switch ON again.
Re-start the commissioning assistant.
Note
If a stable flame is not formed during the sensor test,
repeat the test several times.