Goodman GRL SERIES Installation Instructions Manual page 31

FIGURE 26
TYPICAL GAS VALVE
INLET
PRESSURE TAP
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
Iron Pipe
Size, Inches 10 20 30
1/2 275 189 152
3/4 567 393 315
1 1,071 732 590
1-1/4 2,205 1,496 1,212 1,039
1-1/2 3,307 2,299 1,858 1,559
2 6,221 4,331 3,465 2,992
Example (LP): Input BTU requirement of unit, 120,000
Equivalent length of pipe, 60 ft. = 3/4" IPS required.
FIGURE 27
TYPICAL MANIFOLD PRESSURE READING
Length of Pipe, Feet
40 50 60 70 80
129 114 103 96 89
267 237 217 196 182
504 448 409 378 346
913 834 771 724
1,417 1,275 1,181 1,086 1,023
2,646 2,394 2,205 2,047 1,921
HIGH FIRE
MANIFOLD
PRESSURE
ADJUSTMENT
LOW FIRE
PRESSURE
MANIFOLD
ADJUSTMENT
OUTLET
PRESSURE
TAP
90 100 125 150
83 78 69 63
173 162 146 132
322 307 275 252
677 630 567 511
976 866 787
1,811 1,606 1,496
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.
31