Checking The Fuse - Viessmann VITODENS 111-W Installation And Service Instructions Manual

Troubleshooting
Repairs
(cont.)
A
2x
B
Fig. 44
1. Undo plate heat exchanger
pull out forwards.
2. Check the connections on the heating water and
DHW side for contamination and scaling; if
required, replace the plate heat exchanger.

Checking the fuse

Fig. 45
1. Switch off the power supply.
2. Open control unit enclosure (see page 15).
3. Check fuse F4.
48
(screws ) and
A B
F4
3. Install in reverse order using new gaskets.