Viessmann VITODENS 100-W Installation And Service Instructions Manual page 76

Troubleshooting
Repairs
(cont.)
Checking plate heat exchanger
C DHW
D Cold water
1. Switch OFF the mains power.
2. Close the gas shut-off valve and
safeguard against reopening.
3. Shut off and drain the boiler on the
primary and the secondary side.
Draining on the primary side (see
page 71).
4. Flip down control unit.
76
E Heating water return
F Heating water flow
5. Remove two screws A at the plate
heat exchanger and B remove.
Note
During removal, small amounts of
water may trickle out and escape
from the removed plate heat
exchanger.
6. Check the secondary side for con-
tamination and, if necessary, clean
or replace the plate heat exchan-
ger.