Gas Water Heater Installation
44
5. Cascade system Plumbing Pipe Size (@ NR/NP-240(A))
Q’ty
△
T=86
ºF
Flowrate
(GPM)
Velocity
of Water
(ft/s)
Pipe
Diameter
(mm/in)
Q
’ty
△
T=86
ºF
Flowrate
(GPM)
Velocity
of Water
(ft/s)
Pipe
Diameter
(mm/in)
1
7.19
4.78
20A
3/4”
16
115.07
5.44
80A
3
”
2
14.38
5.61
25A
1”
17
122.26
5.81
80A
3
”
3
21.57
5.54
30A
11/4”
18
129.45
6.14
80A
3
”
4
28.77
5.21
40A
1
1/2”
19
136.64
6.46
80A
3
”
5
35.96
6.53
40A
11/2”
20
143.83
6.83
80A
3
”
6
43.15
4.49
50A
2”
21
151.02
4.06
100A
4
”
7
50.34
5.24
50A
2”
22
158.21
4.25
100A
4
”
8
57.5
6.00
50A
2”
23
165.41
4.45
100A
4
”
9
64.72
4.39
65A
21/2”
24
172.60
4.65
100A
4
”
10
71.92
4.75
65A
21/2”
25
179.79
4.85
100A
4
”
11
79.11
5.34
65A
21/2”
26
186.98
5.05
100A
4
”
12
86.30
5.84
65A
21/2”
27
194.17
5.24
100A
4
”
13
93.49
6.33
65A
21/2”
28
201.36
5.44
100A
4
”
14
100.68
6.79
65A
21/2”
29
208.56
5.61
100A
4
”
15
107.87
5.11
80A
3”
30
215.75
5.81
100A
4
”
If the flow rate inside pipes is over 6.6 ft/s, corrosion might be occurred
inside the pipes.
Above state may be different depending on installation circumstance.
