5

1.6 GENERATOR FUEL SYSTEM

The unit has been factory tested and adjusted using
a natural gas fuel system. If propane (LP) gas is nec-
essary, refer to "Reconfiguring the Fuel System" for
conversion instructions.
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 Coolant
Level Sensor
Low Oil Pressure Switch
High Coolant
Temperature 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).
NOTE:
The Low Oil Pressure, High Coolant Temperature
and Low Coolant Level are not monitored for the
first 10 seconds of engine run time.
Figure 1.4 - Low Oil Pressure Switch

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
Section 1 - General Information
40kW Liquid-cooled Generators