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Trouble
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Cause and Phenomena
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Resolutions
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The motor does not run in lifting operation.
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Connection of power supply wires or zero wire is not correct.
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Check and correct wire connection.
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The AC contactor in the circuit of the motor does not pick up.
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If the motor operates when forcing the contactor down with an isolation rod, check the control circuit. If the voltage at two ends of the contactor coil is normal, replace the contactor.
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The limit switch is not closed.
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Short-circuit terminal 10# and 0#, which are connected with the limit switch, and if the trouble disappears, check the limit switch, wires and adjust or replace the limit switch.
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In lifting operation, the motor runs, but there is no lifting movement.
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The motor turns reverse.
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Change the phases of the power supply wires.
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Lifting with light load is normal but no lifting with heavy load.
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The set safe pressure of the over-flow valve may be increased by turning the set knob right ward slightly.
The spool of the lowering solenoid valve is stuck by dirt. Clean the spool.
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The amount of hydraulic oil is not enough.
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Add hydraulic oil.
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The “operation stop valve” is not open.
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Turn right and open the “Operation stop valve and supply hydraulic oil to main oil cylinder.
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When press “Lower” button, the machine is not lowered.
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The safety pawl are not released form the safety teeth.
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First lift a little and then lowering.
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The safety pawl is not lifted.
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The air pressure is not enough or the safety pawl is stuck.
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The solenoid air valve does not work.
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If the solenoid air valve is energized, but does not open the air loop, check or replace the solenoid air valve.
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The lowering solenoid valve is energized but does not work.
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Check the plug and coil of the lowering solenoid valve and check the right turn tightness of its end copper nut and so on.
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The hydraulic oil has too high viscosity or frozen, deteriorated (in Winter).
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Replace with 20# hydraulic oil in accordance with the instruction book.
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The machine lowers extremely slowly under normal loads.
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The “antiknock valve” for preventing oil pipe burst is blocked.
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Remove or close air supply pipe and thus lock the safety pawl of the machine without lifting of the safety pawl. Remove the “antiknock valve” from the oil supply hole at the bottom of the oil cylinder, and clean the “antiknock valve”.
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Oil leakage on oil pipe or at its connections.
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Tighten oil pipe connections or replace oil seals and then make-up oil and adjust levelness.
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The “oil make-up stop valve” can not be closed tightly and almost make-up oil and adjust every day.
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Replace oil make-up stop valve and then make-up oil and adjust.
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The base or the machine is twisted.
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Adjust again the levelness of the machine, and fill or pad the base.
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