Engine Protective Devices; High Coolant Temperature Sender; Low Coolant Level Sensor; Low Oil Pressure Switch - Generac Power Systems Stationary emergency generator Owner's Manual

ENGINE PROTECTIVE DEVICES

The Stationary Emergency Generator may be required to operate
for long periods of time without an operator on hand to monitor
such engine conditions as coolant temperature, oil pressure or
rpm. For that reason, the engine has several devices designed to
protect it against potentially damaging conditions by automatically
shutting down the unit when the oil pressure is too low, the coolant
temperature is too high, the coolant level is too low, or the engine
is running too fast.
Engine protective switches and sensors are mentioned here for
the reader's convenience. Also refer to the applicable control
panel manual for additional automatic engine shutdown infor-
mation.

HIGH COOLANT TEMPERATURE SENDER

An analog coolant temperture sender, located in the engine's
cooling system will cause an engine shutdown if the temperature
should exceed approximately 125° C (257° F). The generator will
automatically restart once the temperature has returned to a safe
operating level.

LOW COOLANT LEVEL SENSOR

To prevent overheating, the engine has a low coolant level sensor.
If the level of engine coolant drops below the level of the low cool-
ant level sensor, the engine automatically shuts down.

LOW OIL PRESSURE SWITCH

This switch has normally closed contacts that are held open by
engine oil pressure during cranking and operating. Should oil pres-
sure drop below the 8 psi range, switch contacts close, and the
engine shuts down. The unit should not be restarted until oil is
added, and the AUTO/OFF/MANUAL switch must be turned to OFF
and then back to AUTO.
Engine Protective Devices
NOTE:

OVERCRANK SHUTDOWN

After a prespecified duration of cranking, this function ends the
cranking if the engine has failed to start. The overcrank message
will turn ON. Turn OFF the AUTO/OFF/MANUAL switch, then turn
switch back to AUTO to reset the generator control board.
If the fault is not corrected, the overcrank feature will continue
to activate.
Approximate Crank Cycle Times
• 15 seconds ON
• 7 seconds OFF
• 7 seconds ON
• 7 seconds OFF
• Repeat for 45 seconds
• Approximately 90 seconds total.

OVERSPEED SHUTDOWN

A speed circuit controls engine cranking, start-up, operation and
shutdown. Engine speed signals are delivered to the circuit board
whenever the unit is running. Should the engine overspeed above
a safe, preset value, the circuit board initiates an automatic engine
shutdown. Contact the nearest Authorized Dealer if this failure
occurs.

RPM SENSOR LOSS SHUTDOWN

If the speed signal to the control panel is lost, engine shutdown
will occur.

DC FUSES

A fuse (7.5 amp) is located on the control panel. It protects the
panel components from damaging overload. Always remove this
fuse before commencing work on the generator. The unit will not
start or crank if the fuse is blown.
A fuse (25 amp) is located in the engine wire harness adjacent
to the DC alternator. It is used to prevent circuit failure due to DC
alternator falure. It will also protect the system in the event of a
wiring short-dircuit. If this fuse is blown, the generator will not
operate. Replace these fuses with the same size, type, and rating.
4-1
NOTE:
05/10 B Rev. EngProt003