Absolute Boilers 750-900-1050
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Absolute Boilers 750-900-1050
6.1.3 Gas line piping to boiler
Ensure pipe sizing capability follows the recommend values based on an overall length of pipe from the meter plus the
equivalent length of all fittings. Approximate sizing may be based on 1 cubic foot of natural gas supply per 1,000 BTU/
hour input. For example, a 1,000,000 BTU input boiler would require 1000 cubic feet of natural gas.
Nominal
Iron
Pipe
Size
(inches)
Internal
Diameter
(Inches)
Equivalent
Length
Maximum Capacity in Cubic Feet of Natural Gas per Hour
Pressure Drop of 0.5 inch Water Column/Equivalent of Pipe (in feet)
90 El
(feet)
Tee
(feet)
20
40
60
80
100
150
200
1/2
0.622
1.55
3.1
120
85
66
57
50
40
35
3/4
0.824
2.06
4.12
250
170
138
118
103
84
72
1
1.049
2.62
5.24
465
320
260
220
195
160
135
1-1/4
1.380
3.45
6.9
950
660
530
460
400
325
280
1-1/2
1.610
4.02
8.04
14600
990
810
690
620
500
430
2
2.067
5.17
10.3
2750
1900
1520
1300
1150
950
800
2-1/2
2.469
6.16
12.3
4350
3000
2400
2050
1850
1500
1280
3
3.088
7.67
15.3
7700
5300
4300
3700
3250
2650
2280
4
4.026
10.1
20.2
15000
10900
8800
8800
6700
5500
4600
6.2 Gas pressures
The boiler has been factory test fired and adjusted for proper combustion. The boilers main gas valve are certified and
can accept a maximum inlet pressure up to ½ psi or 14 “w.c. [35 mbar], but MUST provided with a min. of 3.5 “w.c.
[8 mbar] at the gas filter inlet test point when the boiler is operating at max output. Pressures below this level can
result in lockouts (for multi gas appliance installations this minimum pressure must be available at each boiler with all
gas appliances firing on max output).
WARNING
All threaded connections must be made using a pipe compound that is resistant to the action of liquefied petroleum
gases. Use only approved gas line type pipe sealant
Gas system pressure checks:
-
The boiler main gas supply shutoff valve and piping must be isolated from any gas piping pressure testing in excess
of ½ psi or 14 ”w.c. [35 mbar]
-
The boiler main gas shutoff valve and piping must be isolated by closing the main gas shutoff valve during gas
piping pressure testing less than ½ psi [3.5 kPa]
-
The boiler main gas piping and gas train must be leak tested prior to placing the boiler in operation
