Viessmann VITODENS 333 Service Instructions Manual page 89

Repairs
(cont.)
Checking plate heat exchanger
1. Shut off and drain the boiler on the
primary and the secondary side.
2. Release the side closures and
pivot the control unit forward.
3. Remove the siphon.
4. Release fittings A, screws B and
pull plate heat exchanger C for-
ward.
Note
During removal, small amounts of
water may trickle out and escape
from the removed plate heat
exchanger.
5. Check the secondary side for scal-
ing and, if necessary, replace the
plate heat exchanger.
6. Check the primary connections for
contamination and, if necessary,
replace the plate heat exchanger.
7. Install in reverse order using new
gaskets. Lubricate the new gas-
kets/seals.
Troubleshooting
89