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| Illustration 1 | g01232017 |
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 main power relay, and the fire suppression pressure switch.
Note: The idle timer/fire suppression control unit, the idle timer control unit or the fire suppression control unit have the same power input and power output connections.
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| Illustration 2 | g01222427 |
(1) Fire suppression activated indicator (2) Idle timer on indicator (3) Engine shutdown switch (4) System reset switch (5) Idle timer/fire suppression control unit | |
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| Illustration 3 | g01236904 |
(6) Main power relay | |
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| Illustration 4 | g01237410 |
Typical example (7) Fire suppression pressure switch | |
With the key start switch in the ON position, 24 volt power is supplied from the batteries to main power relay (6), and to circuit breaker 6.
When main power relay (6) is energized, 24 volt power is supplied to the circuit breaker panel.
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 the fire suppression system. With the fire suppression system activated, fire system activated indicator (1) will flash red and the sonar alarm will sound. After a six second delay idle timer/fire suppression control unit (5) will de-energize main power relay (6) .
When main power relay (6) is de-energized, the contacts will be open, disconnecting the 24 volt power supply to the circuit breaker panel. The Engine ECM and the Power Train ECM will not receive 24 volt power. This will cause the engine to shutdown.
Holding system reset switch (4) in the depressed position will maintain 24 volt power to main power relay (6). When system reset switch (4) has been released idle timer/fire suppression control unit (5) will maintain power to main power relay (6) for a further six seconds.
When the key start switch is turned to the OFF position idle timer/fire suppression control unit (5) illuminates fire suppression activated indicator (1) and continues to provide power to main power relay (6). After three minutes of engine idle time, idle timer/fire suppression control unit (5) interrupts power to main power relay (6). Main power relay (6) will de-energize and the engine will shutdown.
Depressing engine shutdown switch (3) at any time will interrupt 24 volt power to main power relay (6). This will shutdown the engine.