Relief Valve (Medium Pressure Function) - Test and Adjust - Main
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345C MHPU Mobile Hydraulic Power Unit Hydraulic System
[UENR0865]
345C MHPU Mobile Hydraulic Power Unit Hydraulic System
Work Tool Parameter - Default Values - Medium Pressure
345C MHPU Mobile Hydraulic Power Unit Hydraulic System
Work Tool Parameter - Default Values - System 17
HYDRAULIC SYSTEM
VALVE GP-RELIEF
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345C MHPU Mobile Hydraulic Power Unit Hydraulic System
Relief Valve (Medium Pressure Function) - Test and Adjust - Main
- Position the machine on level ground and stop the engine.
- Release the pressure in the hydraulic system. Refer to Testing and Adjusting, "Hydraulic System Pressure - Release" for the machine.
- Install a pressure gauge with a 60000 kPa (8700 psi) capacity on pressure tap (5) for the medium pressure.
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| Illustration 1 | g01635456 |
Medium pressure valve (side view of the swing motor compartment) (3) Medium pressure valve (4) Adjustment screw (main relief valve) (5) Pressure tap (medium pressure) | |
- Start the engine.
- Place the machine controls at the following settings: engine speed dial 10 and AEC switch OFF. Refer to Testing and Adjusting, "Engine Performance - Test (Engine Speed)" for the machine for engine rpm settings.
- Warm the hydraulic oil to 50 °C (122 °F).
- Set the pilot pressure to the specifications in Testing and Adjusting, "Relief Valve (Pilot) - Test and Adjust" for the machine.
- Calibrate the solenoid valves for medium pressure. Refer to Testing and Adjusting, "Medium Pressure: Solenoid Valve (Proportional Reducing) - Calibrate" for the Tool Control System.
- Set the auxiliary tool mode for medium pressure. Refer to Testing and Adjusting, "Work Tool - Select" for the Tool Control System.
- To adjust the pressure setting of the relief valve for medium pressure, press the device for activation for this procedure. Hold the device for activation in this position.
Note: Relief action of the relief valve for more than 10 seconds is not allowed.
Note: To prevent oil flow to the work tool during this testing and adjusting procedure, close the stop valves in the lines for the work tool.
- Check the pressure at pressure tap (5) for medium pressure.
- Return the device for activation to the NEUTRAL position.
- Compare the pressure reading to the specification 21000 ± 500 kPa (3046 ± 73 psi). If the pressure reading is within the specification, no further adjustment is necessary. If the pressure reading is not within the specification, then proceed to Step 14.
- The adjustment screw for the main relief valve is located on the side of valve (3). Turn adjustment screw (4) until the pressure gauge reading at pressure tap (5) is 21000 ± 500 kPa (3046 ± 73 psi).
Note: Turning adjustment screw (4) clockwise increases the pressure. Turning adjustment screw (4) counterclockwise decreases the pressure.
Note: Always make final pressure adjustment on pressure rise.
- Press the device for activation in the opposite direction. Hold the device for activation in this position.
- Check the pressure at pressure tap (5) for medium pressure.
- Return the device for activation to the NEUTRAL position.
- Compare the pressure reading to the specification 21000 ± 500 kPa (3046 ± 73 psi). If the pressure reading is within the specification, no further adjustment is necessary. If the pressure reading is not within the specification, then proceed to Step 14.
Information System:
336D MHPU Mobile Hydraulic Power Unit Hydraulic System
Relief Valve (Auxiliary) - Test and Adjust - Line, System 18
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Work Tool Parameter - Default Values - Medium Pressure
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