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

Repairs
(cont.)
3. Push the three-way valve drive A
slightly upwards.
4. Turn the three-way valve B with
drive A 1/8 anticlockwise and
remove.
5. Remove two screws C from the
plate-type heat exchanger and
remove plate-type heat exchanger
D with gaskets.
Note
During removal, small amounts of
water may trickle out and escape
from the removed plate-type heat
exchanger.
Checking the fuse
1. Switch OFF the power.
6. Check the DHW side for scaling and,
if required, clean or replace the plate-
type heat exchanger.
7. Check the heating water side for con-
tamination and, if required, clean or
replace the plate-type heat
exchanger.
8. Install in reverse order with new gas-
kets.
Note
Ensure that fixing holes and gaskets
are aligned. Install the heat plate
exchanger the correct way round.
F4
2. Open control unit casing (see
page 13).
Troubleshooting
47