Venting and Combustion Air Guide
07/21/11 AERCO International, Inc.
•
100 Oritani Dr.
•
Blauvelt, NY 10913
•
Ph: 800-526-0288 Page
169
of
200
GF-5050
TAG-0043_0C
Pg 16 of 22
3.4 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 heater are as follows:
Model No.
INN600
INN800
INN1060
Vent Diameter
4”
(102 mm)
6
(152 mm)
6
(152 mm)
Maximum Vent
Equivalent Feet (Meters)
140 ft.
(42.7 m)
140 ft.
(42.7 m)
140 ft.
(42.7 m)
Equivalent Vent Length Examples
Model No.
Vent Pipe
Diameter
Sharp 90°
Elbow
Equiv. Ft.
(m)
Sweep 90°
Elbow
Equiv. Ft.
(m)
45° Elbow
Equiv. Ft.
(m)
Equiv. Ft.
(m)
Maximum
Length
Equiv. Ft
(m)
INN600
4”
(102 mm)
10 ft.
(3.05 m)
5 ft.
(1.5 m)
5 ft.
(1.5 m)
5 ft.
(1.5 m)
140 ft.
(42.7 m)
INN800
INN1060
6”
(152 mm)
10 ft.
(3.05 m)
N/A
5 ft.
(1.5 m)
5 ft.
(1.5 m)
140 ft.
(42.7 m)
The maximum pressure drop of the combustion air piping is also 140 equivalent feet (42.7 m). See
Section 2.2. Note that this does
NOT
mean the allowed combined pressure drop between the vent and
combustion air is 280 equivalent feet (85.3 m). That is, the vent cannot go above 140 equivalent feet
(42.7 m), even if the combustion air is less than 140 equivalent feet, and vice versa.
Examples:
1. A 40 foot (12.2 m) length of vent pipe and 1 sharp 90° elbow plus a termination rain cap add up to
40 ft + 10 ft + 10 ft = 60 equivalent ft. (18.3 m)
2. A 30 foot (10.4 m) length of vent pipe and 2 sharp 90° elbows plus a termination rain add up to 30
ft + (2 x 10 ft) + 10 ft = 50 equivalent ft (18.3 m).
Pg 17 of 22
