Guardian Technologies 004988-4 - Manual (Page 7)

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1.6 GENERATOR FUEL SYSTEM
The unit has been factory tested and adjusted using a
natural gas fuel system. If propane (LP) gas is neces-
sary, contact an authorized service dealer.
Fuel pressure for a natural gas set up should be five
inches to 14 inches of water column (0.18 to 0.5
psi) at all load ranges.
Fuel pressure for an LP vapor set up should be 11
inches to 14 inches of water column (0.4 to 0.5
psi) at all load ranges.
NOTE:
A seperate gas line and regulator may be needed
to assure proper gas pressure to the generator.
Improper gas pressure can cause hard starting and
affect engine durability.

Gaseous fuels such as natural and LP (propane)
gas are highly explosive. Even the slightest
spark can ignite such fuels and cause an explo-
sion. 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.
1.7 ENGINE PROTECTIVE DEVICES
The engine has several safety switches which cause
the engine to automatically shut down under the
following conditions: low oil pressure, high coolant
temperature, engine overspeed, low coolant level or
overcrank (Figure 1.3).
Figure 1.3 - Engine Protective Devices
LOW OIL
PRESURE
SWITCH
SWITCH
COOLANT
TEMPERATURE
HIGH
LOW COOLANT
LEVEL SWITCH
1.7.1 LOW OIL PRESSURE SWITCH
This switch is normally-closed (N.C.) but is held open
by engine oil pressure during engine running. Should
operating oil pressure drop below about 8-10 psi (55-
68 kPa), the switch contacts close, the engine shuts
down automatically, and the low oil pressure LED is
turned ON (Figure 1.4).
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Figure 1.4 - Low Oil Pressure Switch
NOTE:
The Low Oil Pressure, High Coolant Temperature
and Low Coolant Level are not monitored for the
first 10 seconds of engine run time.
1.7.2 HIGH COOLANT TEMPERATURE
SWITCH
This normally open (N.O.) thermostatic switch has
sensing tip which is immersed in captive coolant.
Should coolant temperature exceed about 230°F
(110°C), the switch contacts close. This causes the
engine to shut down automatically and turns on
the high coolant temperature/low coolant level LED
(Figure 1.5).
Figure 1.5- High Coolant Temperature Switch
1.7.3 LOW COOLANT LEVEL SWITCH
Should engine coolant level drop below the level of
the high coolant temperature switch, it is possible for
the engine to overheat without automatic shutdown.
To prevent such overheating without automatic shut
down, the engine has a low coolant level sensor. If the
engine coolant drops too low, the engine automatical-
ly shuts down and turns on the high coolant tempera-
ture/low coolant level LED (Figure 1.6 on page 6).
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Section 1 - General Information
Liquid-cooled 30 kW Generators