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| Illustration 1 | g02556015 |
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Schematic of the pilot hydraulic system (1) Pilot oil filter (2) Pilot pressure relief valve (3) Hydraulic cooling fan (4) Fan control solenoid valve (5) Reversing fan control (6) Fan control solenoid valve (7) Travel speed solenoid valve (8) Swing parking brake solenoid (9) Swing motor (10) Pilot on/off solenoid valve (11) Pilot manifold (12) Pressure control valve (13) Implement control valve (14) Pilot oil pump (15) Travel control valve (16) Travel motors (17) Hydraulic tank (18) Intermittent saw valve (if equipped) | |
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| Illustration 2 | g01388859 |
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Location of the pilot manifold | |
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| Illustration 3 | g02556178 |
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Pilot manifold (4) Fan control solenoid valve (5) Reversing fan control solenoid valve (6) Fan control solenoid valve (7) Travel speed solenoid valve (8) Swing parking brake solenoid (10) Pilot on/off solenoid valve | |
The pilot hydraulic system contains the following components: pilot oil pump (14), pilot oil filter (1), pilot pressure relief valve (2), pilot manifold (11), hydraulic cooling fan (3), fan solenoids (4), (5), and (6), travel speed solenoid valve (7), swing parking brake solenoid (8) and pilot on/off solenoid valve (10).
The pilot hydraulic system receives oil flow from pilot oil pump (14). The pilot oil pump is mechanically connected to the main pump.
Reference: For more information about the pilot oil pump, refer to Systems Operation/Testing and Adjusting, "Gear Pump (Pilot)".
The pilot oil pump draws oil from the case of the main pump. The pilot oil flows through pilot oil filter (1) to pilot manifold (11). The pilot oil filter has a bypass valve and a pressure relief valve (2) in the filter base.
The pilot hydraulic system controls the following functions:
(1) The pilot hydraulic system supplies pilot oil to selector and pressure control valve (12).
The selector and pressure control valve regulates the lowering of the boom, when the engine is stopped.
When the engine is operating, pilot oil pump (14) sends pilot oil through filter (1) to selector and pressure control valve (12) and manifold (11). The pilot oil shifts selector and pressure control valve (12) to the CLOSED position.
When the engine is stopped, the pilot oil flow is stopped. The selector and pressure control valve shifts. Pressurized oil from the boom up circuit flows through the pilot manifold to the solenoid valves on the boom control valve.
When the joystick control is moved to BOOM DOWN, the pressurized oil flows through the solenoid valve to the spool in the control valve. The spool shifts allowing the boom to be lowered.
Note: The engine start key must be in the ON position and the hydraulic lockout must be in the UNLOCKED position.
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| Illustration 4 | g01388857 |
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Hydraulic lockout (pilot oil) on later machines (19) LOCKED position (20) UNLOCKED position | |
Note: When the hydraulic lockout is in the LOCKED position (19), no implement functions will operate.
(2) The pilot hydraulic system supplies pilot oil to optional hydraulic cooling fan (3). Hydraulic cooling fan (3) operates at pilot system pressure. Pilot oil will flow into pilot manifold (11) to fan control solenoid valves (4) and (6).
Fan control solenoids (4) and (6) are activated when sensors for the coolant temperature, hydraulic oil temperature, and engine inlet manifold temperature reach set point. A signal is sent from the IQAN controller to fan control solenoid valves (4), and (6) and reversing fan control solenoid (5).
In order for the hydraulic cooling fan to draw in air, fan control solenoid (6) and reversing fan control solenoid (5) must be energized. Oil will flow to fan control solenoid (6) then to the hydraulic cooling fan (3). Oil will flow from the hydraulic cooling fan (3) through fan control solenoid (4). The oil will then flow from fan control solenoid (4) to the hydraulic tank.
When the hydraulic cooling fan is NEUTRAL, fan control solenoids (4) and (6) must be de-energized and reversing fan control solenoid (5) must be energized. This process will not allow oil to flow to the hydraulic cooling fan (3).
In order for the hydraulic cooling fan to push air, the fan control solenoid (4) and reversing fan control solenoid (5) must be energized. Oil will flow to fan control solenoid (4) then to the hydraulic cooling fan (3).
A manual override switch inside the operator compartment switches the fan to the reverse direction. This procedure is for removing debris from the radiator.
Reference: Refer to the System Operation, RENR3699, "Flexxaire Fan" manual for additional information.
(3) The pilot hydraulic system supplies pilot oil to travel speed solenoid valve (7).
The travel speed solenoid controls the speed of the machine in forward direction or reverse direction. When travel speed solenoid valve (7) is de-energized and the hydraulic lockout is in the UNLOCKED position (20), the machine will travel in high speed. When travel speed solenoid valve (7) is energized by the travel speed control switch inside the operator compartment, pilot oil flows to the travel motors. The machine will travel in low speed.
Reference: For more information on the travel speed of the machine, refer to Systems Operation/Testing and Adjusting, "Travel System".
(4) The pilot hydraulic system supplies pilot oil in order to release the swing parking brake.
When swing parking brake solenoid (8) is energized, and the hydraulic lockout is UNLOCKED (20), pilot oil flows to the swing parking brake. The swing parking brake is released.
(5) The pilot hydraulic system supplies pilot oil to implement control valve (13) and travel control valve (15).
When the hydraulic lockout is in the UNLOCKED position (20), pilot solenoid valve (10) is energized. Pilot oil flows from pilot manifold (11) to the proportional solenoid valves of the implement control valve and the travel control valve.
When an implement is activated, the pilot oil flows through the proportional solenoid valve to the spool of the control valve. The control valve shifts allowing pressurized oil to flow from the implement pump to the implement.