Generac Power Systems 04389-3 - Manual (Page 9)

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1.6 SYSTEM SET LED
The “System Set” LED is lit when all of the following
conditions are true:
1. The AUTO/OFF/MANUAL switch is set to the
AUTO position.
2. The utility voltage being supplied to the unit is
being sensed by the PCB. If the utility sense volt-
age is not connected to the unit or if it is below
168 volts AC, then the system set light will flash
rapidly. This indicates that if the AUTO/OFF/
MANUAL switch is placed in the Auto position,
the generator will start.
3. The “Not In Auto” dip switch is set to the OFF
position on the control board.
4. No alarms are present, for example, low oil pres-
sure, high temperature, etc.
1.7 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, 10 inches to 12 inches of water
column (0.36 to 0.43 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
column for liquid propane for all load ranges.
1.8 FUEL CONSUMPTION
*Natural gas is in cubic feet per hour.
**LP is in gallons per hour/cubic feet per hour.
*** Values given are approximate.
DANGER

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.
1.9 RECONFIGURING THE
FUEL SYSTEM
1.9.1 7 KW, 410CC ENGINE
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 10 to 12 inches of water column (0.36 to
0.43 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.
Figure 1.3 – Demand Regulator
NG FUEL SYSTEM LP FUEL SYSTEM
FUEL HOSE
BRASS HOSE
FITTING
BRASS HOSE
FITTING
FUEL JET
OUTLET
PORT
FUEL HOSE
ADJUSTMENT
SCREW
HOSE & PLUG
SWITCHED SIDES
PIPE
PLUG
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Section 1 — General Information
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
04389 66 119 0.82/30 1.47/54
04456 152 215 1.53/56 2.08/76
04390 156 220 1.58/58 2.40/88