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| Illustration 1 | g01001147 |
Idle timer/fire suppression control circuit | |
The components of the idle timer/fire suppression control circuit are the idle timer/fire suppression control unit, the Engine Electronic Control Module (Engine ECM), the fire suppression pressure switch and the main power relay.
Note: The idle timer/fire suppression control unit, idle timer control unit and the fire suppression control unit are options. The power inputs and power outputs have the same connections for all the control units.
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| Illustration 2 | g00996562 |
View below the dash panel (1) Fire system activated indicator (2) Engine shutdown switch (3) System reset switch (4) Idle timer/fire suppression control unit | |
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| Illustration 3 | g00996565 |
Left side view of engine (5) Engine ECM | |
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| Illustration 4 | g00996567 |
Front view of cab (front cover plate removed) (6) Main power relay (7) Fire suppression pressure switch | |
With the key start switch in the ON position, 24 volt power is supplied from the batteries to the main power relay. Power is also supplied from the batteries via circuit breaker #3 to the idle timer/fire suppression control unit and then to the main power relay. With the main power relay energized, 24 volt power is supplied to the Engine ECM. This will enable the engine to run.
If the fire suppression system pressure decreases to 860 ± 170 kPa (125 ± 25 psi), fire suppression pressure switch (7) will activate. This will provide a ground connection to activate idle timer/fire suppression control unit (4). With the idle timer/fire suppression control unit activated, fire system activated indicator (1) will flash RED and the sonar alarm will activate. After a six second delay idle timer/fire suppression control unit (4) will de-energize main power relay (6) .
When the main power relay is de-energized, 24 volt power is interrupted to Engine ECM (5) causing the engine to shutdown.
Holding system reset switch (3) in the depressed position will maintain 24 volt power to the main power relay. When the reset switch has been released the idle timer/fire suppression control unit will maintain power to the main power relay for a further six seconds.
With the key start switch in the OFF position, the idle timer/fire suppression control unit illuminates fire system activated indicator (1) and continues to provide power to the main power relay. After three minutes of engine idle time, the idle timer/fire suppression control unit interrupts power to the main power relay causing the relay to de-energize and the machine will shutdown.
Depressing engine shutdown switch (2) at any time will interrupt power to the main power relay. This will shutdown the engine.