Viessmann VITODENS 222-F Service Instructions Manual page 81

Vitodens 222-F B2TA 19 and 35 Service
Corrective Action
(continued)
Checking the plate heat exchanger
Note: Drain the boiler on its heating water and DHW side.
During removal, small amounts of water may trickle
out and escape from the plate heat exchanger.
1. Shut off and drain the boiler on the heating water and
DHW sides.
2. Release the side closures and pivot the control unit
forward.
3. Remove the siphon (see page 23).
4. Push insulating mat A upwards and remove.
5. Undo two screws B and pull out plate heat
exchanger C to the front.
6. Check the connections on the heating water and
DHW side for contamination and scaling; if required,
replace the plate heat exchanger.
7. Install in reverse order with new gaskets.
Troubleshooting
81