Fuel Factors
An important consideration affecting the entire installation is the type of fuel used by your generator. The system was factory tested and adjusted using natural gas, but can be converted to use LP vapor. For proper engine function, factors that are inherent to each of these fuels, your location and the duration of possible utility interruptions are important considerations in the following fuel guidelines:
• Use clean, dry fuel, free of moisture or any particulate material. Using fuels outside the following recommended values may cause performance problems.

Fuel Pressure

Both LP vapor and natural gas fuel supply pressure at the generator’s fuel inlet port should be between the following levels at full load with all gas appliances turned on and operating.

• NG is 5-7” W.C.

• LP is 11-14” W.C.

Ensure that all gas line shutoff valves are OPEN and that adequate fuel pressure is available whenever automatic operation is desired.

 

• In engines set up to run on propane (LP), commercial

Power Loss

 

grade HD5 propane with a minimum fuel energy of

 

Air density is less at high altitudes, resulting in less available

 

2500 BTUs/ft3 with maximum propylene content of

 

5% and butane and heavier gas content of 2.5% and

engine power. Specifically, engine power will decrease 3.5%

 

minimum propane content of 90% is required.

for each 1,000 feet (300 m) above sea level and 1% for

Natural gas rating will depend on specific fuel but typical

each 10° F (5.6°C) above 77°F (25°C). Generators located in

these conditions must have their transfer switch adjusted

derates are between 10 to 20% off the LP gas rating.

appropriately for this power decrease. See Automatic

Natural gas or LP engines are certified to operate on natural

Transfer Switch manual on how to adjust for the power

or liquid propane gas. The emissions control system for this

decrease.

engine is EM (Engine Modifications).

 

 

 

 

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

 

WARNING Propane and Natural Gas are extremely flammable

common resource.

 

and explosive, which could cause burns, fire or

The installer should consider the specific gravity of gas

 

explosion resulting in death or serious injury.

 

and compensate for a nominal amount of restriction from

 

The residential generator is equippedNOTwith an aut matic safety

•

bends, fittings, etc. If an unusual number of fittings, bends, or

 

gas “fuel shut-off” valve.

 

 

other restrictions are used, refer to federal and local codes

•

DO NOT operate the equipment if the “fuel shut-off” valve is

for guidance.

 

missing or inoperative.

for

REPRODUCTION

 

 

 

 

 

 

 

 

 

 

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