31
TABLE 5
LP GAS PIPE CAPACITY TABLE (CU. FT./HR.)
Maximum capacity of pipe in thousands of BTU per hour of undiluted liquefied petroleum gases (at 11 inches water
column inlet pressure).
(Based on a Pressure Drop of 0.5 Inch Water Column)
Nominal
Length of Pipe, Feet
Iron Pipe
Size, 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
393
315
267
237
217
196
182
173
162
146
132
1
1,071
732
590
504
448
409
378
346
322
307
275
252
1-1/4
2,205
1,496
1,212
1,039
913
834
771
724
677
630
567
511
1-1/2
3,307
2,299
1,858
1,559
1,417
1,275
1,181
1,086
1,023
976
866
787
2
6,221
4,331
3,465
2,992
2,646
2,394
2,205
2,047
1,921
1,811
1,606
1,496
Example (LP): Input BTU requirement of unit, 120,000
Equivalent length of pipe, 60 ft. = 3/4" IPS required.
9. Note or adjust the manifold
pressure to give:
A. 1.7" w.c. for natural gas low
fire.
B. 4.8" w.c. for LP gas low fire.
10. To adjust the pressure regulator
for low fire, remove the regulator
cap
on the top of the regulator.
See Figure 27.
11. Turn the adjustment screw
clockwise to increase pressure or
counterclockwise to decrease
pressure.
12. Securely replace the regulator
cap for low fire.
13. Verify pressures for high and low
fire operation.
14. Shut off gas at the manual gas
valve and remove the U-Tube
manometer.
15. Replace the manifold pressure
tap plug before turning on gas.
Check for leak.
FIGURE 26
TYPICAL GAS VALVE
INLET
PRESSURE TAP
OUTLET
PRESSURE
TAP
HIGH FIRE
MANIFOLD
PRESSURE
ADJUSTMENT
LOW FIRE
PRESSURE
MANIFOLD
ADJUSTMENT
FIGURE 27
TYPICAL MANIFOLD PRESSURE READING
