Viessmann VITODENS 222-F Installation And Service Instructions Manual page 127

Repairs
(cont.)
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 28).
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 heat-
ing water and DHW side for contam-
ination and scaling; if required,
replace the plate heat exchanger.
7. Install in reverse order with new gas-
kets.
Troubleshooting
127