LOFA MC536 Operation and Troubleshooting
Revision - A - 22-May-2006 3
Operation
Turning the control system key to the run position starts a self-test which causes all LEDs to flash three times
and enables the fuel run/stop solenoid output. After self-test, the LEDs indicate the state of the inputs they
monitor. The normal indications are battery charge and oil pressure on most applications. If these LEDs are
not illuminated at this time it may indicate the inputs are not properly connected.
The Preheat LED is illuminated when the key switch is turned to the run position if automatic preheat is
configured (See Preheat Options). Preheat time varies from application to application. After waiting for the
Preheat LED to extinguish, the engine is cranked by turning and holding the key switch in the start position
until the engine starts. The key switch is spring loaded to return automatically to the run position when
released. The Preheat LED is illuminated during afterglow if enabled.
Note
The key switch is equipped with a mechanical start locking device.
An attempt to re-crank the engine can only be made by turning the key switch
to the off position to reset the start locking mechanism.
If the engine is not started within 30 seconds of turning on the system, the fuel run/stop solenoid output is
turned off to prevent battery discharge when the key switch is left in the run position. The fuel run/stop
solenoid output is turned off after 30 seconds even if preheating. As soon as the key switch is turned to the
start position the solenoid output is enabled. The afterglow cycle begins when the key switch returns to the
run position.
Note
If conditions do not warrant preheat, the engine may be started by turning the key to the start
position without waiting for the preheat time to expire.
Control system instrument power, including the hourmeter and voltmeter, is provided by the fuel run/stop
solenoid output. If the instruments do not power up when the key is turned to the run position, this indicates
a problem with the solenoid circuit (see Troubleshooting).
After the engine starts, the control system electronics ignore all shutdown conditions for the first 10 seconds.
This delay eliminates the requirement to hold a by-pass override button during starting and allows the system
conditions such as oil pressure to normalize. The 10 second timer starts when the key switch returns to the
run position.
Note
Starter input is required for correct system operation. If the starter motor input is not activated
(connected to battery positive) and the engine is started through another means (i.e. air
starter) the engine will shutdown 30seconds after the key switch is turned to the run position.
To prevent unintentional engine shutdowns caused by intermittent conditions (i.e., pressure spikes, coolant
movement) the control system requires a constant 1/3 seconds fault input to cause engine shutdown.
Warning
When used in combination with mechanical float type switches
engine vibrations may prevent constant contact closure.
