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4. Release the internal pressure of the hydraulic system
The hydraulic oil in the hydraulic pipeline is at high temperature and high pressure when the machine is working
intermittently. The oil may spray out when removing the oil port, so turn the oil filler cap before removing the cap to relieve
internal pressure.
1) If the working device is not in the state shown in the
figure, start the engine at a low speed, extend the bucket
cylinder, and retract the stick cylinder. Then land the
bucket and turn off the engine.
2) Within 15 seconds after turning off the engine, turn the
start switch to the ON position, and operate the joystick
(working device, walking) in each direction to release the
internal pressure.
5. Safe operation of accumulator
Warning: The accumulator is a component filled with high pressure nitrogen, which may
cause explosion and other hazards if used incorrectly. The accumulator cannot be
disassembled, and the operation such as drilling and welding also cannot be carried out
on it. Avoid the accumulator from being close to the fire source, and avoid collision and
impact on the accumulator. Professional personnel shall be invited to dispose the
accumulator.
The machine is equipped with accumulators in the control
pipeline. The accumulators in the control pipeline are the
pressure storage devices. When these devices are
installed, the control pipeline can be operated for a short
time even after the engine stops.
The working device can be lowered under its own weight
by operating the joystick.
Pressure relief method for the control pipeline of the machine equipped with
accumulators
1) Lower the working device to the ground, and then close the hydraulic breaker hammer or other accessories.
2) Turn off the engine.
3) Turn the key of the start switch to the ON position again to make the current flow in the circuit.
4) Adjust the safety lock control lever to the free position, and then operate the joystick of the working device and the
accessory control pedal (if equipped) in the front, rear, left and right directions to release the pressure in the control line.
5) Adjust the safety lock control lever to the LOCK position in order to lock the control lever and the accessory control
pedal.
High pressure
nitrogen hazard
Summary of Contents for U27
Page 1: ...U27Hydraulic Excavator Instruction Manual Guangxi Yuchai Heavy Industry Co Ltd...
Page 5: ...1 1 Preface...
Page 17: ...2 1 Safety regulations...
Page 44: ...3 1 Parts introduction...
Page 49: ...3 6 Panel meter Oil level pointer Timing display Water temperature pointer Indicator area...
Page 55: ...4 1 Operation guide...
Page 89: ...5 1 Maintenance...
Page 130: ...6 1 Accessories guide...