Viessmann Vitodens 100 WB1A Installation And Service Instructions Manual page 34

Installation
Installing the boiler and making all connections
A Heating flow: 722 mm
B DHW: 715 mm
C Gas connection: ½ BSP
System boiler
For operation without a DHW cylinder, shut-off connections B and D.
A Heating flow: 722 mm
B DHW cylinder flow: 722 mm
34
(cont.)
D Cold water: 715 mm
E Heating return: 722 mm
C Gas connection: ½ BSP
D DHW return: 722 mm
E Heating return: 722 mm