Gas connections and gas regulator, For natural gas, For lp gas – Bosch 125B LPS User Manual
Page 10: Gas line sizing, Fig. 4
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GAS CONNECTIONS and Gas Regulator
NOTE: The Aquastar 125 B”S” is supplied with a gas pressure regulator that must be installed on the heater before
attaching the gas supply line. See figure 5. Failure to install the gas regulator as shown in figure 5 will be a violation
of CSA certification of the unit. The regulator supplied with the heater is preset for the gas shown on the rating
plate to the correct pressure. It is an appliance level regulator designed for (low inlet) pressure (less than 1/2 Psig
or 15” W.C.) DO NOT connect to an unregulated or high pressure propane line or to a high pressure commercial
natural gas line.
FOR NATURAL GAS
Maximum Capacity of pipe in Cubic Feet of Gas per Hour
for Gas Pressure of 0.5 Psig or less and a Pressure drop of
0.3 in Water Column.
(Based on a 0.60 Specific Gravity Gas) Btu numbers given
in thousands.
Follow boxed numbers for piping just one Aquastar 125BS
(example: 3/4” B.I. Natural Gas pipe for 30 ft. will handle
152,000 btu’s). For multiple appliances combine the total
btu input load and then refer to applicable chart below.
FOR LP GAS
Maximum Capacity of Pipe in Thousands of
BTU per Hour of Undiluted Petroleum Gases
(at 11 inches Water Column Inlet Pressure)
(Based on a Pressure Drop of 0.5 Inch Wa-
ter Column).
Maximum Capacity of Semi-Rigid
Tubing in Thousands of BTU per Hour of
Undiluted Liquified Petroleum Gases (at 11
inches Water Column Inlet Pressure)
(Based on a Pressure Drop of 0.5 Inch Water
Column)
* Source National Fuel Gas Code NFPA 54, ANSI Z223.1 - No
Additional Allowance is necessary for an ordinary number of fittings
GAS LINE SIZING
Nominal
Iron
Length of Black Iron Pipe, Feet
Pipe
Internal
Size,
Diameter
inches inches
10
20
30
40
50
60
70
80
90
100
125
150
175
200
1/4
0.364
32
22
18
15
14
12
11
11
10
9
8
8
7
6
3/8
0.493
72
49
40
34
30
27
25
23
22
21
18
17
15
14
1/2
0.622
132
92
73
63
56
50
46
43
40
38
34
31
28
26
3/4
0.824
278
190
152
130
115
105
96
90
84
79
72
64
59
55
1
1.049
520
350
285
245
215
195
180
170
160
150
130
120
110
100
1 1/4
1.380
1050
730
590
500
440
400
370
350
320
305
275
250
225
210
1 1/2
1.610
1600
1100
890
760
670
610
560
530
490
460
410
380
350
320
2
2.067
3050
2100
1650
1450
1270
1150
1050
990
930
870
780
710
650
610
2 1/2
2.469
4800
3300
2700
2300
2000
1850
1700
1600
1500
1400
1250
1130
1050
980
3
3.068
8500
5900
4700
4100
3600
3250
3000
2800
2600
2500
2200
2000
1850
1700
4
4.026
17,500 12,000 9,700 8,300
7,400 6,80
6,200 5,800 5,400 5,100 4,500
4,100 3,800 3500
Nominal
Iron Pipe
Black Iron Pipe
Size,
Length of Pipe, Feet
Inches
10
20
30
40
50
60
70
80
90
100
125
150
1/2
275 189 152
129 114 103
96
89
83
78
69
63
3/4
567 693 315
267 237 217 196 185 173
162
146
132
1
107 732 590
504 448 409 378 346 322
307
275
252
1 1/4
220 149 121
103 913 834 771 724 677
630
567
511
1 1/2
330 229 185
155 141 127 118 108 102
976
866
787
2
622 433 346
299 264 239 220 204 192 1811 1606 1496
Copper
Outside
Length of Tubing, Feet
Diameter,
Inch
10
20
30
40
50
60
70
80
90
100
3/8
39
26
21
19
_
_
_
_
_
_
1/2
92
62
50
41
37
35
31
29
27
26
5/8
199 131
107
90
79
72
67
62
59
55
3/4
329 216
181
145
131
121 112 104
95
90
7/8
501 346
277
233
198
187 164 155 146 138
Fig. 4