Fuel System
FUEL SYSTEM
FUEL REQUIREMENTS
The Stationary Emergency Generator may be equipped with one of the following fuel systems:
•Natural gas fuel system
•Propane vapor (LPV) fuel system
Recommended fuels should have a Btu content of at least 1,000 Btu's per cubic foot for natural gas; or at least 2,520 Btu's per cubic foot for LP gas. Ask the fuel supplier for the Btu content of the fuel.
NOTE:
The fuel consumption requirements are identified in the Specifications section of the Owner's Manual. Refer to the Installation Manual if assistance is required for the sizing of the pipe diameter for the generator. Any piping used to connect the generator to the fuel supply should be of adequate size to achieve the 100% load fuel consumption requirements identified in the Specifications section regardless of actual load.
NOTE:
The recommended fuel pressure is identified in the Specifications section this manual.
NOTE:
It is the responsibility of the installer to make sure that only the correct recommended fuel is supplied to the generator fuel system. Thereafter, the owner/operator must make certain that only the proper fuel is supplied.
NATURAL GAS FUEL SYSTEM
Natural gas is supplied in its vapor state. In most cases, the gas distribution company provides piping from the main gas distribution line to the standby generator site. The following information applies to natural gas fuel systems.
•Gas pressure in a building is usually regulated by national, state and local codes.
•To reduce gas pressure to a safe level before the gas enters a building, a primary regulator is needed. The natural gas supplier may or may not supply such a regulator.
•It is the responsibility of the gas supplier to make sure sufficient gas pressure is available to operate the primary regulator.
•Gas pressure at the inlet to the fuel shutoff solenoid must never exceed approximately 14 inches water column (0.5 psi).
PROPANE VAPOR WITHDRAWAL FUEL SYSTEM
This type of system utilizes the vapors formed above the liquid fuel in the supply tank. Approximately 10 to 20 percent of the tank capacity is needed for fuel expansion from the liquid to the vapor state. The vapor withdrawal system is generally best suited for smaller engines that require less fuel. The installer should be aware of the following:
•When ambient temperatures are low and engine fuel consump- tion is high, the vapor withdrawal system may not function efficiently.
•Ambient temperatures around the supply tank must be high enough to sustain adequate vaporization, or the system will not deliver the needed fuel volume.
•In addition to the cooling effects of ambient air, the vaporization process itself provides an additional cooling effect.
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