Vent Length Requirements; Maximum Vent Pipe Length - Horizontal - Viessmann Vitodens 100-W WB1A-24 Installation Instructions Manual

Single Wall Venting (Room Air Dependent)

Vent Length Requirements

Maximum vent pipe length - horizontal

Table 46. Maximum allowable equivalent length - horizontal
Boiler Model
HWB1A 8-24, 8-30
HWB2 6-24C, 6-24
HWB2 8-32
HWB2 11-44
HWB2 15-60
*1
2" diameter system only available with CPVC system
*2
4" (3" to 4" increaser field supplied. Do not order Viessmann 4" parallel adaptor).
Maximum of five 90° elbows allowed in the entire vent system. See Fig. 47
Minimum vent length is 3.3 ft. / 1m.
Field supplied
exhaust vent pipe
and fittings
Fig. 60
Legend
Support system
Exhaust vent termination
Combustion air intake
Combustion air opening
a Equivalent vent length (exhaust)
70
System Ø Max. equivalent
*1
2" / 51mm
3" / 76mm
*2
4" / 102mm
3" / 76mm
4" / 102mm
3" / 76mm
4" / 102mm
4" / 102mm
4" / 102mm
Starter adaptor
vent length (a)
33ft. / 1m
52ft. / 16m
66ft. / 20m
52ft. / 16m
63ft. / 19.2m
40ft. / 12m
50ft. / 15.2m
52ft. / 16m
40ft. / 12m
a
Size the exhaust vent pipe as specified
in the table on the left. This table lists
the maximum allowable vent length in
ft. and meters of the exhaust piping.
Vent diameter must not be reduced at
any point in the installation.
IMPORTANT
First elbow not included in equivalent
vent calculation.
Always include vent termination length
in calculations.
Side wall
Caulk here
(exterior caulking)
Flue