Vent Length Requirements; Maximum Vent Pipe Length - Horizontal; Minimum Vent Length Is 3.3 Ft. (1 M); In. (51 Mm) - Viessmann Vitodens 100-W WB1B Series Installation Instructions Manual

Rigid Venting Systems Installation Instructions

Vent Length Requirements

Maximum vent pipe length - horizontal

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 the table 35.
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 35 Maximum allowable equivalent length - horizontal
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) system
*2
4 in. (3 in. to 4 in. increaser field supplied).
*3
See figure 80.

Minimum vent length is 3.3 ft. (1 m).

Flue starter adaptor -Stainless Steel & CPVC (all boilers)
C
C
Fig. 80 Vitodens 100-W and 200-W WB2B 19, 26, 35
Legend
A Support system
B Exhaust vent termination
C Combustion air intake (left, right or through co-axial
opening), remove and discard air intake cover (WB1B
26, 35 and WB2B 19, 26, 35)
D Combustion air opening
a Equivalent vent length (exhaust)
Single Pipe Venting (Room Air Dependent)
First elbow not included in equivalent vent calculation.
Always include vent termination length in calculations.
System Ø

2 in. (51 mm)*

3 in. (76 mm)*

4 in. (102 mm)*
2 in. (51 mm)*
3 in. (76 mm)*
4 in. (102 mm)*
3 in. (76 mm)
4 in. (102 mm)*
4 in. (102 mm)
A
- PP(s) (WB2B 80, 105 only)
D
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).
IMPORTANT
Max. equivalent vent length "a"*
1
2
2
1
2
2
2
a
IMPORTANT
3
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)

Side wall
Caulk here
(exterior caulking)
B
Flue
77