87
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:
A
Fig. 53
1.
Pull the leads from temperature limiter
A
.
2.
Check the continuity of the temperature limiter with
a multimeter.
3.
Remove the faulty temperature limiter.
4.
Coat the replacement temperature limiter with heat
conducting paste and install it.
5.
After commissioning, press reset button
R
on the
control unit.
Checking the fuse
F1
A
Fig. 54
1.
Switch off the power.
2.
Release the side closures and pivot the control unit
down.
3.
Remove cover
A
.
4.
Check fuse F1 (see connection and wiring dia-
gram).
Troubleshooting
Repair
(cont.)
5772 980 GB
Service