4.A manual main gas shutoff valve is provided outside the jacket, upstream of the main gas valve.
5.In Canada, derated10% from 2,000 - 4,500 ft., over 4,500 ft. derate must be in accordance with local authorities. Consult factory for installations at higher elevations.
High Altitude Applications
Atmospheric pressure decreases as the height above sea level increases. At any altitude above sea level, a cubic foot will contain less gas than a cubic foot at sea level. Thus, the heating value of a cubic foot of fuel gas will decrease as height above sea level increases.
Specific gravity of a gas with respect to sea level also decreases with altitude. These changes in heating value and specific gravity tend to offset each other.
However, as elevation above sea level is increased, there is less oxygen per cubic foot
of air. Therefore, heat input rate should be reduced in an appliance above 2000 feet. Ratings should be reduced at the rate of 4 percent for each 1000 feet above sea level.
(TABLE E) – INLET GAS PRESSURE
MODELS | NAT. GAS | LP GAS |
CW |
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Minimum Allowable | 4” | 8” |
Maximum Allowable | 10.5” | 13” |
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CW |
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Minimum Allowable | 4.5” | 8” |
Maximum Allowable | 10.5” | 13” |
WATER CONNECTIONS
Inlet and Outlet Water Connections
For ease of service, install unions on inlet and outlet of the water heater.
The connection on the unit marked “Inlet” should be used for return water from the storage tank. The connection on the header marked “Outlet” should be connected to the inlet of the storage tank. (See Appendix A for Water Heater Piping Diagrams).
EXAMPLE OF HIGH ALTITUDE APPLICATIONS
For example, if a unit’s input is 100,000 Btu/hr at sea level, the rated input at 4000 feet of elevation can be calculated by derating input 4% per 1000 feet above sea level.
[Btu/hr Input]
[1.00 - (Elevation/ 1000 ft. x 0.04)] = Btu/hr Input at specified elevation. [100,000][1.00 - (4000 ft. /1000 ft. x 0.04)]
=Btu/hr Input 4000’ elevation. [100,000][0.84] = 84,000 Btu/hr Input at 4000 ft. elevation.
(TABLE D) – GAS SUPPLY PIPE SIZING
Length of Pipe In Straight Feet
Nominal Iron |
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Pipe Size, Inches | 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 |
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1 | 697 | 477 | 384 | 328 | 292 | 267 | 256 | 246 | 210 | 200 | 179 | 164 | 149 | 138 |
11/4 | 1,400 | 974 | 789 | 677 | 595 | 543 | 502 | 472 | 441 | 410 | 369 | 333 | 308 | 287 |
11/2 | 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 |
21/2 | 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 | 7,900 | 6,400 | 5,400 | 4,870 | 4,410 | 4,000 | 3,800 | 3,540 | 3,300 | 3,000 | 2,720 | 2,500 | 2,340 |
31/2 | 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 0.05 Inch Water Column (Based on NAT GAS, 1025 BTU’s per Cubic Foot of Gas and 0.60 Specific Gravity).
L o c h i n v a r D E S I G N E R ’ S G U I D E C O P P E R - F I N W A T E R H E A T E R 6 1 5 - 8 8 9 - 8 9 0 0 | 1 1 |
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