Viessmann VITODENS 100-W Installation And Service Instructions Manual page 75

Repairs
(cont.)
4. Check the connections on the DHW
side for scaling; clean or replace the
plate heat exchanger if required.
5. Check the connections on the heat-
ing water side for contamination;
clean or replace the plate heat
exchanger if required.
Checking the fuse
1. Switch off the power supply.
2. Open control unit enclosure (see
page 20).
3. Check fuse F4.
6. Install in reverse order using new
gaskets.
Note
During installation, ensure the fixing
holes are aligned and the gaskets are
seated correctly. Mount the plate
heat exchanger with the correct ori-
entation.
F4
Troubleshooting
75