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Generac
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Power Systems, Inc. 7
1.6 FUEL REQUIREMENTS
AND RECOMMENDATIONS
With LP gas, use only the vapor withdrawal
system. This type of system uses the vapors formed
above the liquid fuel in the storage tank.
The engine has been fitted with a fuel carburetion
system that meets the specifications of the 1997
California Air Resources Board for tamper-proof dual
fuel systems. The unit will run on natural gas or LP
gas, but it has been factory set to run on natural gas.
Should the primary fuel need to be changed to LP
gas, the fuel system needs to be reconfigured. See
Section 1.9 for instructions on reconfiguration of the
fuel system.
Recommended fuels should have a Btu content of at
least 1,000 Btus per cubic foot for natural gas; or at
least 2,520 Btus per cubic foot for LP gas. Ask the
fuel supplier for the Btu content of the fuel.
Required fuel pressure for natural gas is 5 inches to
7 inches water colum (0.18 to 0.25 psi); and for
liquid propane, 11 inches to 14 inches of water
column (0.4 to 0.5 psi).
NOTE:
Any piping used to connect the generator to the
fuel supply should be of adequate size to ensure
the fuel pressure NEVER drops below 4 inches
water colum for natural gas or 10 inches water col-
umn for liquid propane for all load ranges.
1.7 FUEL CONSUMPTION
*Natural gas is in cubic feet per hour.
**LP is in gallons per hour/cubic feet per hour.
1.8 RECONFIGURING THE
FUEL SYSTEM
1.8.1 7 KW, 410CC
To reconfigure the fuel system from NG to LP,
follow these steps (Figure 1.3):
NOTE:
The primary regulator for the propane supply is
NOT INCLUDED with the generator. A fuel pres-
sure of 11 to 14 inches of water column (0.4 to 0.5
psi) to the fuel inlet of the generator MUST BE
SUPPLIED.
1. Turn off the main gas supply (if connected).
2. Open the roof and remove the door.
3. Remove the battery (if installed).
4. Disconnect wire #0 and wire #14 from the gas
solenoid on top of the demand regulator.
5. Remove the carburetor fuel hose from the outlet
port of the demand regulator.
6. Remove the demand regulator by removing the
fastener that retains the regulator mounting
bracket.
7. Remove the square headed steel pipe plug from
outlet port #1 and the brass hose barb fitting
from outlet port #2.
8. Refit the brass hose barb fitting to outlet port #1
and the square headed steel pipe plug to outlet
port #2.
9. Reverse procedure steps 1-5 to reinstall demand
regulator.
10. Reverse the procedure to convert back to natural
gas.
Figure 1.3 – Demand Regulator
NOTE:
The natural gas adjustment screw is preset during
installation and should not need any further
adjustment.
1.8.2 12KW AND 15KW, V-TWIN ENGINES
To reconfigure the fuel system from NG to LP,
follow these steps:
NOTE:
The primary regulator for the propane supply is
NOT INCLUDED with the generator. A fuel pres-
sure of 11 to 14 inches of water column (0.4 to 0.5
psi) to the fuel inlet of the generator MUST BE
SUPPLIED.
1. Turn off the gas supply. (if connected)
2. Open the roof and remove the door.
3. Remove the battery. (if installed)
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◆
Section 1 — General Information
Generac Air-cooled 7 kW, 12 kW and 15 kW Generators
Model # Nat. Gas (*) LP Vapor (**)
1/2 Load Full Load 1/2 Load Full Load
04673 66 119 0.82/30 1.47/54
04674 152 215 1.53/56 2.08/76
04675 156 220 1.58/58 2.40/88