Viessmann VITOLADENS 300-W Installation And Service Instructions Manual page 109

Repair
(cont.)
Checking the fuse
1. Switch off the power.
2. Release the side closures and pivot
the control unit down.
Extension kit, mixer
Checking the setting of rotary selec-
tor S1
The rotary selector on the PCB of the
extension kit defines the assignment to
the relevant heating circuit.
F1
3. Remove cover A.
4. Check fuse F1 (see connection and
wiring diagram).
Heating circuit
Heating circuit with mix-
er M2
(heating circuit 2)
Heating circuit with mix-
er M3
(heating circuit 3)
Troubleshooting
Rotary se-
lector S1 set-
ting
2
4
109