Installation guide

Direct Venting (Two-pipe System)
48
Vent Requirements - Stainless Steel (continued)
Additional requirements for stainless steel vent pipe material (continued)
Viessmann coaxial increaser and 2” air intake CPVC adaptor must be ordered, (see table 33. for part number).
Minimum pipe diameter available for exhaust stainless steel pipe is 3”.
The air intake pipe of the increaser must be removed and discarded (See Fig. 34).
The air inlet (intake) cover must stay in place.
Table 33. Coaxial increaser (min. stainless steel pipe diameter is 3” / 76mm)
Supplier
Boiler Model Coaxial increaser CVPC Starter Adaptor
for air intake
Qty.
Viessmann HWB1B 10-26, 10-35
HWB2B 9-19/26/35
(60>3”)
(see Fig. 35)
2” 1
Vent pipe starter adaptors
for WB1B 10-26, 10-35 and
WB2B 9-19, 9-26, 9-35
5368 815 v2.0 b
Fig. 34
Air intake
outer pipe
d
e
c
b
Air
a
Flue
A
B
Air inlet (intake)
cover must stay
in place.
DO NOT remove!
Optional
left connection
for air intake
Fig. 35
Legend
A Stainless steel slip joint vent
starter adaptor
B 2” CVPC starter adaptor,
ViPN 7134 769
a3”/76mm
b2”/51mm
c 6.25” / 159mm
d 10.34” / 263 mm
e3”/76mm
(For this type of installation only:)
Boiler comes with pre-installed
combustion air cover mounted on the
concentric vent pipe adaptor. Do not
remove combustion air intake cover.
Removing this cover may cause
unintended room air dependent
operation (non-direct vent). Room air
dependent operation requires provisio
n
of combustion and ventilation air (as
per section “Single Wall Venting”,
p. 64.
WARNING