Modulex Light Commercial Series
CHAPTER 4: Installation Instructions
OMM-0158_A
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4.25 Vent Pipe Sizing
The maximum length is the combined length of straight horizontal and vertical runs, and the
equivalent straight length of fittings. The required lengths for each boiler are as follows:
NOTE:
The examples referenced in the table below are on the next page.
TABLE 4-4: Modulex EXT Vent and Piping Diameter Chart
Model
No. of
Modules
Vent Diameter
Inches (Mm)
Max. Vent Equiv.
Feet (M)
Examples 1 & 2
Max. Vent Equiv.
Feet (M)
Examples 3 & 4
EXT 450 2S
3
4” (101 mm)
100 ft. (30 m)
6 + 6 (1.8 + 1.8)
EXT 600 2S
4
6
” (101 mm)
100 ft. (30 m)
6 + 6 (1.8 + 1.8)
EXT 800 2S
5
6
” (
152 mm)
100 ft. (30 m)
6 + 6 (1.8 + 1.8)
EXT 1100 2S
7
6” (152 mm)
100 ft. (30 m)
6 + 6 (1.8 + 1.8)
TABLE 4-5: Modulex EXT Vent and Piping Length Chart
Model
Vent Pipe
Dia.
Sharp 90° Elbow
Equivalent
Feet (M)
Sweep 90°
Elbow
Equivalent
Feet (M)
45° Elbow
Equivalent
Feet (M)
Maximum Length
Equivalent
Feet (Meters)
EXT 450 2S
4”
(101 mm)
10 Feet
(3 m)
5 Feet
(1.5 m)
5 Feet
(1.5 m)
100 Feet
(30 m)
EXT 600 2S
6”
(152 mm)
10 Feet
(3 m)
5 Feet
(1.5 m)
5 Feet
(1.5 m)
100 Feet
(30 m)
EXT 800 2S
EXT 1100 2S
NOTE:
maximum pressure drop of the combustion air piping is also 100 equivalent feet (30 m).
The flue system must be installed in accordance with the local and national Standards.
EXAMPLE 1:
A 40 foot (12.2 m) length of vent pipe and 1 sharp 90° elbow add up to 40 ft. + 10
ft. = 50 equivalent ft. (17.4 m).
EXAMPLE 2:
A 30 foot (10.4 m) length of vent pipe and 2 sharp 90° elbows add up to 30 ft. + (2
x 10 ft.) = 50 equivalent ft. (17.4 m).
