Vent Length Requirements; Maximum Vent/Air Intake Pipe Length - Horizontal - Viessmann Vitodens 200-W WB2B Series Installation Instructions Manual

Vitodens Rigid and Flex Venting Systems Installation

Vent Length Requirements

Maximum vent/air intake pipe length - horizontal

IMPORTANT
Always include vent termination length in calculations.
Maximum allowable equivalent length - horizontal
Boiler Model
WB1B 26, 35
WB2B 19, 26, 35, B2HA 19, 28, 35, B2HB 19, 26, 35,
B2TA 19, 35, B2TB 19, 35
WB2B 45, 60, B2HA 45, 60, B2HB 45, 57
WB2B 80, 105, B2HA 80, 88, 100, 112
B2HA 150
* 1 2 in. to 3 in. or 2 in. to 4 in. increaser field supplied.
* 2 See illustrations below.
* 3 Due to higher exhaust vent pipe resistance, there is an automatic input reduction of 9% for model B2HA 150
when a 4 inch diameter vent pipe is used.
* 4 4 in. to 5 in. increaser field supplied.
Note: For combination of different vent/air intake pipe diameters, such as Ø 3 in. stainless steel vent with Ø 2 in.
(CVPC, PVC, ABS) air intake pipe, the total equivalent length must be used for the smaller pipe diameter.
Minimum vent length is 3.3 ft. (1 m).
First elbows not
included in equivalent
vent length calculation
Vitodens 100-W WB1B 26, 35, 222-F B2TA 19, 35
B2TB 19, 35, 200-W WB2B 19, 26, 35, 200-W B2HA 19,
28, 35, B2HB 19, 26, 35
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
See note below
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)
4 in. (100 mm)*
5 in. (125 mm)*
Flue starter adaptor
Air intake starter adaptor
Boiler vent pipe adaptor
For PP(s) see page 64.
Direct Venting (Two-pipe System)
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 lengths.
See table and illustration below for reference.
All PP(s) vent material and air intake (if PP(s) used) must
be ULC S636 or UL1738 listed, manufactured by M&G /
DuraVent or Centrotherm.
Max. combined equivalent vent length
(a+b)*
98 ft. (30 m)
164 ft. (50 m)
200 ft. (61 m)
1
115 ft. (35 m)
1 148 ft. (45 m)
180 ft. (55 m)
1
98 ft. (30 m)
1 148 ft. (45 m)
131 ft. (40 m)
3 131 ft. (40 m)
4 131 ft. (40 m)
Legend
A Support system
B Exhaust pipe termination with screen
C Combustion air intake with screen
a Equivalent vent length (exhaust)
b Equivalent vent length (air intake)
2
Side wall
Caulk here
(Exterior caulking)
Flue
Air
43