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5608 741 - 04
Vitodens Rigid and Flex Venting Systems Installation
Direct Venting (Two-pipe System)
Vent Length Requirements
Maximum vent/air intake pipe length - horizontal
IMPORTANT
Always include vent termination length in calculations.
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.
Maximum allowable equivalent length - horizontal
Boiler Model
System Ø
See note below
Max. combined equivalent vent length
(a+b)*
2
WB1B 26, 35
2 in. (51 mm)
3 in. (76 mm
4 in. (102 mm)*
1
98 ft. (30 m)
164 ft. (50 m)
200 ft. (61 m)
WB2B 19, 26, 35, B2HA 19, 28, 35, B2HB 19, 26, 35,
B2TA 19, 35, B2TB 19, 35
2 in. (51 mm)
3 in. (76 mm)*
1
4 in. (102 mm)*
1
115 ft. (35 m)
148 ft. (45 m)
180 ft. (55 m)
WB2B 45, 60, B2HA 45, 60, B2HB 45, 57
3 in. (76 mm)
4 in. (102 mm)*
1
98 ft. (30 m)
148 ft. (45 m)
WB2B 80, 105, B2HA 80, 88, 100, 112
4 in. (102 mm)
131 ft. (40 m)
B2HA 150
4 in. (100 mm)*
3
5 in. (125 mm)*
4
131 ft. (40 m)
131 ft. (40 m)
*
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).
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
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)
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
Flue
Air
Caulk here
(Exterior caulking)
Side wall
Flue starter adaptor
Air intake starter adaptor
Boiler vent pipe adaptor
For PP(s) see page 64.
First elbows not
included in equivalent
vent length calculation