Maximum Vent/Air Intake Pipe Length - Vertical - Viessmann Vitodens 100-W WB1A-24 Installation Instructions Manual

Direct Venting (Two-pipe System)
Vent Length Requirements

Maximum vent/air intake pipe length - vertical

Table 36. Maximum allowable equivalent length - vertical
Boiler Model
HWB1A 8-24, 8-30
HWB2 6-24C, 6-24
HWB2 8-32
HWB2 11-44
HWB2 15-60
*
4" (3" to 4" increaser field supplied. Do not order Viessmann 4" parallel adaptor).
Maximum of five 90° elbows allowed in the entire vent and air intake system. See Fig. 47.
Minimum vent length is 3.3 ft. / 1m.
52
(continued)
System Ø Max. combined
vent length (a+b)
3" / 76mm
*
4" / 102mm
3" / 76mm
4" / 102mm
3" / 76mm
4" / 102mm
4" / 102mm
(for larger Ø system
consult Viessmann)
4" / 102mm
(for larger Ø system
consult Viessmann)
Legend
Support system
Flashings
Exhaust (straight coupling) with
screen
Combustion air intake with screen
a Equivalent length (exhaust)
b Equivalent length (air intake)
c min. 18" / max. 48"
d min. 12"
e min. 12"
f 6" over max. local snow level
(check with your local weather
office for details)
The total equivalent length specified for
a two pipe system is the total
combined length of the exhaust vent
and air intake pipe system. Do not
exceed these maximum lenghts. See
table 36., as well as Figs. 44, 45, and
46 for reference.
equivalent
66ft. / 20m
79ft. / 24m
66ft. / 20m
79ft. / 24m
49ft. / 15m
62ft. / 19m
66ft. / 20m
49ft. / 15m
a
Vertical Vent Installation
d
e
c
f
b
Fig. 45