Innovation Series & ReCon Water Heater
GF-5050
Venting and Combustion Air Guide
TAG-0043_0Q
12/01/2016
AERCO International, Inc.
•
100 Oritani Dr.
•
Blauvelt, New York 10913
•
Phone: 800-526-0288
Page
37
of
39
Example using standard North American units of measure:
1) An installer is trying to figure out if he can save some money by using a 4-inch vent (exhaust)
design versus a 6-inch when installing a single Innovation 600 water heater. After laying out
the design, he determines he needs the following components:
a) A 15-foot length of combustion air pipe with one (1) sharp 90° elbow plus (2) two
termination 90° elbows.
b) A 35-foot length of vent pipe and two (2) sharp 90° elbows plus a termination (exit cone
or rain cap).
Intake (must use 6-inch):
From
Table 4
for 6-inch piping we will design the inlet for maximum outside air temperatures
(100
°
F):
Max outside air Temp = 100
°
F
∆
p straight pipe = 0.24 ft./ft.
∆
p 90° elbow = 1.24 ft./elbow
∆
p entrance loss = 1.94 ft.
Intake
∆
p equivalent feet = 15 ft. x 0.24 ft./ft. + 3 elbows x 1.24 ft./elbow + 1.94 ft. = 10 feet
Vent using 6” pipe (Exhaust):
From
Table 8
for 6-inch piping:
∆
p straight pipe = 0.3 ft./ft.
∆
p 90° elbow = 1.7 ft./elbow
Velocity cone or Rain cap = 3 ft.
Exhaust
∆
p equivalent feet = 35 ft. x 0.3 ft./f.t + 2 elbows x 1.7 ft./elbow + 3 ft. = 17 feet
Vent using 4” pipe (Exhaust):
From
Table 8
for 4-inch piping:
∆
p straight pipe = 2.2 ft./ft.
∆
p 90° elbow = 12.1 ft./elbow
Velocity cone or Rain cap = 19.7 ft.
Exhaust
∆
p equivalent feet equals:
35 ft. x 2.2 ft./ft. + 2 elbows x 12.1 ft./elbow + 19.7 ft. =
121 feet > 80 feet --FAIL--
i)
Total equivalent feet of intake (6-inch) and vent (6-inch) =
10 ft. + 17 ft. = 27 ft. --APPROVED--
ii)
Total equivalent feet of intake (6-inch) and vent (4-inch) =
10 ft. +
121 ft.
= 131 ft.
--FAIL--
Only the 6-inch design is approved. Note that the 4” vent pipe design failed even though
the total equivalent feet for the combined intake and vent system was less than 140 feet.
The 4 inch vent design exceeded the equivalent 80 foot maximum.
