Viessmann VITODENS 100-W Installation And Service Instructions Manual page 47

Repairs
(cont.)
6. Check the connections on the DHW
side for scaling, and if required clean
or replace the plate heat exchanger.
7. Check the connections on the heat-
ing water side for contamination, and
if required clean or replace the plate
heat exchanger.
Checking the fuse
1. Switch OFF the power.
2. Open control unit casing (see
page 16).
3. Check fuse F4.
8. Install in reverse order using new
gaskets.
Note
Ensure that fixing holes and gaskets
are aligned. Install the plate heat
exchanger with the correct orienta-
tion.
F4
Troubleshooting
47