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Installation and Service Manual
13. Remove the manometer and related fitting from the “inlet” side
of the gas valve, replace 1/8" hex plug in the gas valve and
tighten.
14. Turn on the gas supply at the manual valve, turn on L.P. gas at
the tank if required.
15. Turn the power switch to the “ON” position.
16. Turn the gas valve knobs to the “ON” position.
17. Set the temperature control to call for heat.
ƽ WARNING: After completing any testing on the
gas system, leak test all gas connections. Apply a
soap/water solution to all gas connections while
main burners are operating. Bubbles forming
indicate a leak. Repair all leaks at once. Do not
operate this pool heater with a leak in the gas train,
valves or related piping.
Check burner performance by cycling the system while you observe
burner response. Burners should ignite promptly. Flame pattern
should be stable, see Burner Flames, page 47. Turn system off and
allow burners to cool, then cycle burners again to ensure proper
ignition and flame characteristics.
Figure 30 – Measuring Gas Supply Pressure at Combination
Gas Valve
TABLE - K
Multiple Unit Installations Gas Supply Pipe Sizing
Nominal
Iron Pipe
Size
(Inches)
Length of Pipe in Straight Feet
10 20 30 40 50 60 70 80 90 100 125 150 175 200
3/4" 369 256 205 174 155 141 128 121 113 106 95 86 79 74
1" 697 477 384 328 292 267 246 256 210 200 179 164 149 138
1 1/4" 1,400 974 789 677 595 543 502 472 441 410 369 333 308 287
1 1/2" 2,150 1,500 1,210 1,020 923 830 769 707 666 636 564 513 472 441
2" 4,100 2,820 2,260 1,950 1,720 1,560 1,440 1,330 1,250 1,180 1,100 974 871 820
2 1/2" 6,460 4,460 3,610 3,100 2,720 2,460 2,310 2,100 2,000 1,900 1,700 1,540 1,400 1,300
3" 11,200 8.900 6,400 5,400 4,870 4,410 4,000 3,800 3,540 3,300 3,000 2,720 2,500 2,340
4" 23,500 16,100 13,100 11,100 10,000 9,000 8,300 7,690 7,380 6,870 6,150 5,640 5,130 4,720
Maximum capacity of pipe in thousands of BTU’s per hour for gas pressures of 14 Inches Water Column (0.5 PSIG) or less and a total system pressure drop of 0.5
Inch Water Column (Based on NAT GAS, 1025 BTU’s per Cubic Foot of Gas and 0.60 Specific Gravity).
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