Viessmann VITODENS 343-F WS4A Installation And Service Instructions Manual page 106

Troubleshooting
Repairs
(cont.)
Checking the plate-type heat exchanger
1. Remove cover panel A.
2. Shut off the heating water side of
the compact boiler.
3. Close the on-site shut-off valve.
4. Drain the boiler on the DHW side
via drain valve B.
5. Drain the system on the heating
water side via drain valve C.
106
6. Undo fittings D.
7. Pull the locking bracket from plug-
in connectors E and pull the con-
nections on the heating water
side.