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Fuel Pipe Sizing
There are numerous on-line or otherwise-published
references for fuel pipe sizing. For example, NFPA 54 -
National Fuel Gas Code, 2006 (Item #: 320-6031-06) is
a common resource. The installer should consider the
specific gravity of gas, compensate for a nominal amount of
restriction from bends and fittings, and refer to federal and
local codes for guidance.
Fuel Conversion
The unit is shipped from the factory calibrated for NG
operation. To convert the engine from NG to LP vapor, locate
the fuel selector switch (A) and move the selector switch to
either LP or NG.
Fuel Pressure
Both LP vapor and natural gas fuel supply pressure at the
generator's fuel inlet port should be between 7 to 11 inches
(18 to 28 cm) of water (in. W.C.) at full load with all gas
appliances turned on and operating. Maximimum pressure
drop from static (engine not running) to full load is 0.5 in.
W.C. Maximum pressure with engine OFF at No Load is
13.85 in. W.C.
Power Loss
Air density is less at high altitudes, resulting in less available
engine power. Specifically, engine power will decrease 3%
for each 1,000 feet (300 m) above sea level and 1% for each
10° F (5.6°C) above 77°F (25°C). Generators located in these
conditions, that use power management technology must
have their transfer switch programmed appropriately for this
power decrease.
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Fuel Consumption
Estimated fuel supply requirements at half and full load for
natural gas and LP vapor fuels are shown here.
BTU/hr
CF/ph
m³/ph
GAL/hr
BTU/hr
CF/ph
m³/ph
A
BTU/hr
ft³/hr
m³/hr
Gal/hr
BTU/hr
ft³/hr
m³/hr
Physical Properties
Normal Atmospheric State
Boiling Point (in °F):
Initial
End
Heating Value:
BTU per gallon (Net LHV*)
BTU per gallon (gross**)
Cubic feet (gas)
Density***
Weight†
Octane Number:
Research
Motor
*
LHV (Low Heat Value) is the more realistic rating.
**
Gross heat value does not consider heat lost in the form of water
during combustion.
*** Density is given in "Cubic Feet of Gas per Gallon of Liquid".
†
Weight is given in "Pounds per Gallon of Liquid".
48kW LP Vapor Fuel Consumption
Full Load
1/2 Load
708000
493500
283
197
8.0
5.6
7.9
5.5
48kW Natural Gas Fuel Consumption
Full Load
1/2 Load
662400
464400
662
464
18.8
13.2
62kW LP Vapor Fuel Consumption
Full Load
1/2 Load
800300
581550
320
233
9.1
6.6
8.9
6.5
55kW Natural Gas Fuel Consumption
Full Load
1/2 Load
681500
512040
682
512
19.3
14.5
LP Vapor
Gas
-44
-44
83,340
91,547
2,500
36.39
4.24
110+
97
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Exercise
247500
99
2.8
2.8
Exercise
244800
245
6.9
Exercise
247050
99
2.8
2.8
Exercise
240840
241
6.8
Natural
Gas
Gas
-259
-259
63,310
1,000
57.75
2.65
110+
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