Generac
®
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 1.8 (Page 7) for instructions on reconfigura-
tion 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 your
fuel supplier for the Btu content of your fuel.
Fuel pressure for both natural gas and liquid
propane set ups must be
11 inches to 14 inches of
water column (0.6 psi) at all load ranges
.
NOTE:
A seperate gas line and regulator may be needed
to assure proper gas pressure (11-14”) to the gen-
erator. Low gas pressure can cause hard starting
and could affect engine durability.
1.7
FUEL CONSUMPTION
*Natural gas is in cubic feet per hour.
**LP is in gallons per hour/cubic feet per hour.
Gaseous fuels such as natural gas and liquid
propane (LP) gas are highly explosive. Even the
slightest spark can ignite such fuels and cause
an explosion. No leakage of fuel is permitted.
Natural gas, which is lighter than air, tends to
collect in high areas. LP gas is heavier than air
and tends to settle in low areas.
1.8
RECONFIGURING THE
FUEL SYSTEM
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. You must sup-
ply a fuel pressure of 11 to 14 inches of water col-
umn (0.6 psi) to the fuel inlet of the generator.
1. Turn off the main gas supply.
2. Remove the three carburetor fuel hoses from the
outlet ports of the demand regulator.
3. Disconnect wire #0 and wire #14 from the gas
solenoid located on the top of the demand regu-
lator.
4. Remove the demand regulator from the enclosure
by rotating counterclockwise.
5. Remove the small jet (0D5698A) located in the
side of the regulator housing and install it into the
small threaded hole in the idle circuit port on the
regulator.
7. Refit the brass hose fitting to the idle circuit port
of the regulator. Use pipe thread sealant to reseal
the threads on the hose fitting.
8. Identify both adjustment screws.
NOTE:
One adjustment screw can be accessed from the
front of the unit and the second can be accessed
from the back of the unit.
9. The unit has been factory set to run on NG fuel.
To reset the system to run on LP fuel, turn the
two adjustment screws 1/2 turn clockwise. Use a
large screwdriver to make this adjustment.
10. The fuel system will now allow the engine to run
on LP fuel. It may be necessary to make minor
adjustments to the preset screw settings to
achieve maximum power. If you experience prob-
lems with the unit producing maximum power,
follow the procedure in Section 2.6, “Adjusting
the Regulator”.
11. Reverse procedure steps 1-4 to reinstall the
demand regulator.
Figure 1.2 – Demand Regulator
PRESSURE
U
1
T
O
TAP
1/8 NPT
IDLE CIRCUIT
PORT
BRASS HOSE
FITTING
BRASS HOSE
FITTING
FUEL HOSE
ADJUSTER
SCREWS
REGULATOR
HOUSING PORT
SMALL
FUEL JET
Section 1 — General Information
Air-cooled 8.5 kW Generator
Model #
Nat. Gas (*)
LP Vapor (**)
1/2 Load Full Load
1/2 Load
Full Load
004692-0
114
170
1.33/45.8
1.98/72.5
