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| Illustration 1 | g02718910 |
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(1) Keypad module
(2) CAN data link (3) Engine Control Module (ECM) (4) To Brake System (5) Shuttle Valve (6) Sensor (7) Cut-in/Cut-out Valve (8) Relief Valve (9) Priority Valve (10) Pump (11) Engine PTO (12) Standard Fan Motor (15) Check Valve (16) Fan Solenoid Valve (17) Tank | |
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| Illustration 2 | g02718911 |
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(12) Standard Fan Motor
(15) Check Valve (16) Fan Solenoid Valve (18) Case Drain (19) Outlet (20) Inlet | |
The speed of the fan is controlled by demand fan solenoid valve (16). The demand fan solenoid valve is controlled by the machine ECM. The speed of the fan motor depends on the amount of flow that is allowed through the valve (16) for the fan. The control of the fan speed is based on the value of the following conditions:
- Inlet manifold temperature
- Transmission oil temperature
- Hydraulic oil temperature
- Engine coolant temperature
- Ambient temperature (if the air conditioning is on)
The machine ECM may require more air flow for cooling. If so, the machine ECM will decrease the amount of electric current sent to demand fan solenoid valve (16). This decrease will close the demand fan solenoid valve. When the demand fan solenoid valve closes more, the pressure of pilot oil acting on flow control valve (23) for the fan increases. This action restricts the flow of oil through the flow control valve for the fan. Restricted oil flow through the flow control valve causes oil from the braking and hydraulic fan pump (10) to flow through fan motor (12). The fan motor will turn faster. The speed of the fan depends on the following inputs:
- The amount of current that is sent to the demand fan solenoid valve
- The amount of pump flow that is available
The machine ECM may not require more air flow for cooling. If so, the machine ECM will increase the amount of electric current to the demand fan solenoid valve. This increase will shift the demand fan solenoid valve more open. This action will increase the flow of oil through the flow control valve for the fan. Increased results in less oil flowing to the fan motor. The fan motor will turn more slowly. The speed of the fan depends on the amount of current that is sent to the demand fan solenoid valve.
Makeup valve (15) prevents cavitation of the fan motor during deceleration.
From the fan motor, hydraulic oil flows directly back to the hydraulic oil tank.
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| Illustration 3 | g02718912 |
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(1) Keypad module
(2) CAN data link (3) Engine Control Module (ECM) (4) To Brake System (5) Shuttle Valve (6) Sensor (7) Cut-in/Cut-out Valve (8) Relief Valve (9) Priority Valve (10) Pump (11) Motor (13) Cross-over Relief Valve (14) Reversing Fan Solenoid Valve (if equipped) (15) Check Valve (16) Fan Solenoid Valve (17) Tank (21) Reversing Fan Motor | |
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| Illustration 4 | g02718915 |
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(13) Cross-over Relief Valve
(14) Reversing Fan Solenoid Valve (if equipped) (15) Check Valve (16) Fan Solenoid Valve (18) Case Drain (19) Outlet (20) Inlet (21) Fan Motor | |
The machine can be equipped with a reversing fan. The cooling capacity of the machine is diminished when any of the following components are obstructed with debris:
- The radiator
- The hydraulic oil cooler
- The transmission oil cooler
- The screens in the enclosure doors
The reversing fan allows the debris to be removed without turning off the machine.
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| Illustration 5 | g02666236 |
| (22) Reversing fan switch | |
When the reversing fan switch (22) is pressed, a signal is sent through the Controller Area Network (CAN) to the fan reversing valve (14).
The reversing fan switch sends a signal to the engine ECM. Fan reversing solenoid (14) is controlled by the engine ECM. When the fan reversing solenoid is shifted, pump oil will be directed in the opposite direction through the motor. The fan will turn in the opposite direction.