Maximum Vent Pipe Length - Vertical - Viessmann Vitodens 100-W WB1B Series Installation Instructions Manual

Single Pipe Venting (Room Air Dependent)
Vent Length Requirements

Maximum vent pipe length - vertical

All PP(s) vent material and air intake (if PP(s) used) must
be ULC S636 or UL 1738 listed, manufactured by M&G
(Muelink & Grol b.v.) / DuraVent or Centrotherm.
Size the exhaust vent pipe as specified in table 36. This
table lists the maximum allowable vent length in feet and
meters of the exhaust piping. Vent diameter must not be
reduced at any point in the installation.
Table 36 Maximum allowable equivalent length - vertical
Boiler Model
WB1B 26, 35
g
WB2B 19, 26, 35
g
WB2B 45, 60
g
WB2B 80, 105
g
*1 2 in. diameter system only available with CPVC / PP(s) systems
*2 4 in. (3 in. to 4 in. increaser field supplied).
*3 See figure 81.
Minimum vent length is 3.3 ft. (1 m.)
A
b
C
D
Fig. 81
78
(continued)
B
a
D
E
Rigid Venting Systems Installation Instructions
IMPORTANT
For PP(s) systems, all exhaust vent and air intake piping
and elbows exposed outside, must be UV resistant
polypropylene (supplied by the vent manufacturer).
System Ø
2 in. (51 mm)*
1
3 in. (76 mm)* 2
4 in. (102 mm)* 2
2 in. (51 mm)*
1
3 in. (76 mm)* 2
4 in. (102 mm)* 2
3 in. (76 mm)
4 in. (102 mm)* 2
4 in. (102 mm)
Legend
A Exhaust (straight coupling) with screen
B Flashings
C Support system
D Combustion air intake (left, right or through co-axial
opening), remove and discard air intake cover (WB1B
26, 35 and WB2B 19, 26, 35)
E Combustion air opening
a Equivalent length (exhaust)
b min. 18 in. (457 mm)
max. 48 in. (1219 mm)
Max. equivalent vent length "a"*
86 ft. (31 m)
164 ft. (50 m)
200 ft. (61 m)
115 ft. (35 m)
148 ft. (45 m)
180 ft. (55 m)
98 ft. (30 m)
148 ft. (45 m)
131 ft. (40 m)
3