Alarm switches are set at a less critical tempera ture,
pressure, or level limit than the comparable shutoff
control. The alarm switch warns the operator that an
unsafe operating condition is starting to occur.
Corrective measures should be taken to avoid possible
damage to the engine and/or a possible shutdown of the
It could be hazardous to have the engine stop un
expectantly when engine power is needed. How
ever, if the engine overspeeds, the engine must be
When the preset temperature, pressure or fluid level
occurs, the alarm switch will either turn on a light or an
audible alarm. The light or alarm will continue to
operate until the condition is correct ed. When the
condition is corrected the alarm will automatically reset
and the light will turn off.
The cause of the shutdown must be investigated
and corrected before starting the engine.
Alarm Shutoff Switch
A switch may be installed in the alarm circuit for
silencing the alarm while the engine is stopped for
repairs. Before starting, be sure the switch is moved to
the closed (ON) position, and the warn ing lights are lit.
If the switch is left in the open (OFF) position when
the engine is started, the engine will not be
Testing Indicator Lights
Most control panels are equipped with a test switch.
Turn the switch ON, to check all of the indicator lights for
proper operation. Test the in-
dicator lights periodically. Replace burned out light
Testing Shutoff Devices and Alarms
Have all shutoff controls and alarms on the engine
checked twice a year by your Caterpillar dealer.
It is important that these controls function properly. Their
operating condition can only be checked by simulating
extreme operating conditions under
controlled testing procedures. To avoid damage to the
engine, only authorized personnel should conduct these