Checking The Temperature Limiter - Viessmann Vitoladens 300-W Installation And Service Instructions For Contractors

Maintenance
(cont.)
Fault during commissioning (fault A3)
During commissioning, the control unit checks for cor-
rect placement of the flue gas temperature sensor. If
commissioning is terminated and fault message A3 is
displayed:
1. Check whether the flue gas temperature sensor is
correctly inserted. See previous diagram.

Checking the temperature limiter

If the burner control unit cannot be reset after a fault
shutdown although the boiler water temperature is
below approx. 90 °C, check the following:
A
Fig. 41
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 suc-
cessfully.
1. Disconnect the leads from temperature limiter
2. Check the continuity of the temperature limiter with
a multimeter.
3. Remove faulty temperature limiter.
4. Install a new temperature limiter.
5. After commissioning, press reset button R on the
control unit.
Troubleshooting
.
A
75