Gas - Lochinvar Power-Fin Designer's Manual

Designer's Guide / Power-fin Water Heater
Chapter 3 – Gas Supply
Lochinvar products are designed with the concept of flame control. We develop combustion
systems that tightly control the flow of air and gas to deliver a clean and efficient burn. In
Chapters 1 and 2, we showed the various methods to deliver an ample quantity of air to the
appliance. In Chapter 3, we discuss delivering a steady and reliable supply of gas to the
appliance.
The key to the gas supply is sizing the gas line properly. The Power-fin will require less than a
half a pound of pressure. The following Sizing Chart is based on less than ½ pound of pressure
or less than 14 inches of pressure. The table is derived from the ANSI Z223.1, the National Fuel
Gas Code.
Simply calculate the total linear feet of straight gas pipe. Figure each elbow as equal to five
straight feet of pipe. Working down the column that matches your pipe length, find the value
GREATER THAN the total Btu/hr input of the water heater or water heaters. This will identify the
minimum nominal iron pipe size.
Nominal
Iron
Pipe
Size 10 20
3/4" 369 256
1" 697 477
1 1/4" 1,400 974
1 1/2" 2,150 1,500
2" 4,100 2,820
2 1/2" 6,460 4,460
3" 11,200 7,900
4" 23,500 16,100
The Power-fin features a Negative-Regulation or Neg-Reg gas
combustion system. The gas is introduced upstream of the
combustion blower. As the blower draws air in, the negative
pressure on the inlet of the blower pulls the gas from the gas
valve. The gas/air mixture is pushed through the blower into the
burner. The gas/air mixture filters through the ceramic burner
mesh and is ignited by the Hot Surface Igniter.
On full fire, a crisp blue flame rises off the surface of the burner.
As demand decreases, the operating control reduces the blower
speed. The flame is reduced and touches the burner surface.
The ceramic burner material is designed to burn infra-red safely without being damaged by direct
contact of the flame. Even at this reduced Btu/hr input, the gas/air mixture is balanced to provide
clean, efficient combustion.
GAS PIPE SIZING CHART
Length of Pipe in Straight Feet
30 40 50
205 174 155
384 328 292
789 677 595
1,210 1,020 923
2,260 1,950 1,720 1,560
3,610 3,100 2,720 2,460
6,400 5,400 4,870 4,410
13,100 11,100 10,000 9,000
60 70 80 90
141 128 121 113
267 246 256 210
543 502 472 441
830 769 707 666
1,440 1,330 1,250
2,310 2,100 2,000
4,000 3,800 3,540
8,300 7,690 7,380
21
LOCHINVAR CORPORATION
300 MADDOX SIMPSON PKWY
LEBANON, TN 37090
www.lochinvar.com
100 125 150 175
106 95 86 79
200 179 164 149
410 369 333 308
636 564 513 472
1,180 1,100 974 871
1,900 1,700 1,540 1,400
3,300 3,000 2,720 2,500
6,870 6,150 5,640 5,130

Gas

200
74
138
287
441
820
1,300
2,340
4,720