Generac Power Systems Magnum MGG100M, Operator'S Manual

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General Information
36833 C MGG100M Operating Manual 21
Sourcing Natural Gas
The unit accepts NG vapor, sourced from either of the following.
• A utility supply line
• A wellhead
Natural gas is drawn into the fuel system through the NG inlet port (see Figure 7 ).
Sourcing Liquid Propane
The unit accepts propane liquid, sourced in pressurized tanks.
Note: THIS FUEL SYSTEM DOES NOT ACCEPT PROPANE VAPOR. Propane supply tanks must dispense propane
liquid. Check the regulator on the supply tank to verify LPL is dispensed. If your propane supply tank does not have
a liquid withdrawal system, a licensed propane supply company must install the correct fitting to allow for it.
Liquid propane is drawn into the fuel system through the LPL inlet port (see Figure 7 ). The LPL vaporizer and regulator
converts the liquid to a vapor before introducing the fuel to the engine carburetor.
Fuel Switching
Natural gas is the primary fuel and LPL is the secondary. The unit always selects and uses the primary fuel source,
provided it is available. The primary fuel source is available when input pressure in the primary fuel line is at or above
30 PSI (207 kPa).
Note: Input pressure is fuel pressure in the supply pipe between the fuel source and the unit.
Fuel switching occurs automatically and during unit operation—no operator action is required. At all times, if input
pressure in the NG fuel line drops below 30 PSI (207 kPa) for a certain time frame, the unit switches to the secondary
fuel; and when input pressure in the NG fuel line rises to or above 30 PSI (207 kPa), the unit switches back to the
primary fuel. A fuel sensor measures the input pressure in the primary fuel line.
Note: No sensor is connected to the secondary fuel line. If NG is unavailable and LPL becomes depleted, no fuel
switching is attempted and no warning is delivered, but the unit shuts off.
If NG input pressure drops below 30 PSI (207 kPa) for a certain time frame and no secondary fuel source is available,
the low fuel pressure warning
activates. If the primary fuel source drops below 20 PSI (138 kPa), the unit shuts off.
For more information, see Low Fuel Pressure Warning .