Viessmann Vitodens 200-W WB2B Series Installation Instructions Manual page 60

Single Pipe Venting (Room Air Dependent)
General Installation Information
Additional requirements for stainless steel vent pipe material
(continued)
Coaxial boiler vent pipe connection
Legend
A Combustion air intake
B Flue gas
Starter adaptor for WB2B 45, 60, 80, 105,
B2HA 45, 60, 80, 88, 100, 112, 150
B2HB 45, 57
Legend
A Boiler adaptor
B Stainless steel starter adaptor [max. insertion 2½ in.
(64 mm)]
60
Vitodens Rigid and Flex Venting Systems Installation
(continued)
Combustion
air
Flue
a 6.5 in
a
(165 mm)