CUTTING EDGE (Center) 7J9481 - Caterpillar

Manual Purge Switch - When this feature is enabled, this feature allows manual purges to be performed by depressing the manual purge switch. The switch sends a signal to the ECM in order for the ECM to initiate a purge cycle.Purge Suspend - When this feature is activated, this feature temporarily suspends automatic purges until the ECM receives a signal that allows the automatic purges to occur. This is helpful in operations that require purges at particular times. An example of purge suspend is temporarily suspending automatic purges until the machine is put into REVERSE.
Table 10
Factory Default Settings
Parameter Description Default Setting
Manual Purge The manual purge switch can be enabled or disabled. Enabled
Suspend Purge Suspension of purges can be enabled or disabled. Disabled When suspend purge is disabled, purges occur whenever the counter for the purges reaches zero. When suspend purge is enabled, purges are delayed until the machine is in REVERSE.Systems Operation
When the keyswitch is turned on, the ECM verifies that the hydraulic actuated fan has been enabled. If the fan is enabled, the ECM checks the signal from the temperature sensor. When the “PUSH” solenoid is energized, the solenoid valve allows hydraulic oil to flow to the hub assembly, and the oil moves the blades to the PUSH position. When the “PULL” solenoid is energized, the solenoid valve allows hydraulic oil to flow to the hub assembly, and the oil moves the blades to the PULL position.The pressure from the hydraulic oil moves the fan blades to the PUSH or PULL. When no pressure is sent to the hub assembly the blades return to the NEUTRAL position:PUSH - Air is drawn from the engine compartment and out through the radiator.PULL - Air is drawn through the radiator into the engine compartment.NEUTRAL - This position is used when the engine is cold. When the fan is in this position the fan will produce no air flow across the radiator.Automatic Purge
The system will automatically purge the radiator at the preset intervals. Automatic purges do not occur when the engine is cold. The fan blades are held in NEUTRAL (zero pitch).Timer Controlled System Operation
General Information
Illustration 11 g00897855
Typical Schematic
(1) Timer
(2) Optional Indicator light
(3) Toggle switch for the air flow
(4) Pin 2
(5) Pin 1
(6) Protection device for voltage surges
(7) 18 Gauge Wire
(8) Manual purge switch
(9) Solenoid valve
(10) Fuse (5-15 Amp) In a timer controlled system, the pitch of the fan blades is controlled by only a timer and a solenoid valve. The timer will initiate purges at preset intervals. This timer is also capable of receiving signals from a manual purge switch. When the manual purge switch is pressed or the preset time interval has passed, the timer sends a signal to the solenoid valve. This solenoid valve directs hydraulic oil to the hydraulic connectors on the fan assembly. The pressure from the hydraulic oil allows the fan to change the pitch of the blades. The systems that are controlled only by a timer do not use temperature sensors or position sensors.System Operation
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