Viessmann Vitodens 222-F B2TA Installation And Service Instructions Manual page 138

Troubleshooting
Repair
(cont.)
Drain boiler on the heating water side
1. Close the shut-off valves on the heat-
ing water side.
2. Route hose at drain valve A into a
suitable container or drain outlet.
138
3. Open drain valve A and drain the
boiler as much as required.