Two Post Lift Common Problems

Possible causes

Judgment method

Solution

The lowering throttle valve is tightened too tightly.

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Loosen the nut of the lowering throttle valve core, rotate the valve core counterclockwise, and adjust the appropriate position according to the lowering speed of the hoist.

The hydraulic oil is not clean.

Visually check that the hydraulic oil is not clear and there are sundries.

Replace the hydraulic oil.

There are sundries in the explosion-proof roller valve.

Disassemble the oil cylinder connector and check whether there are sundries.

Clean the explosion-proof throttle valve or replace the oil cylinder connector.

There are sundries in the valve core of the electromagnetic unloading valve.

Disassemble the valve core of the electromagnetic unloading valve and check whether there are sundries.

Clean or replace the solenoid unloading valve spool.

There are sundries in the manual unloading valve.

Disassemble the valve core of manual unloading valve and check whether there are sundries.

Clean or replace the valve element of manual unloading valve.

The oil pipe is blocked inside.

Remove the main oil pipe, connect the removed oil pipe to the joint of the pump station, press the rising button, and visually check whether the oil output of the oil pipe is smooth.

Replace the oil pipe.

Possible causes

Judgment method

Solution

Filter screen of oil suction pipe is blocked.

Remove the screws connecting the valve plate to the oil drum and check whether there are sundries on the filter screen of the oil suction pipe.

Clean the strainer of oil suction pipe.

There are sundries in the valve core of the electromagnetic unloading valve.

Let the lift rise and check whether the machine unloads automatically.

Clean or replace the solenoid unloading valve spool.

Debris in the valve core of manual unloading valve.

Let the lift rise and check whether the machine unloads automatically.

Clean or replace the valve element of manual unloading valve.

Possible causes

Judgment method

Solution

Poor contact of lowering button.

Turn on the power supply, press the descent button, and use a multimeter to check whether the wiring at both ends of the button is powered on.

Replace the lowering button.

The safety lock cannot be opened.

Check whether the value on the air pressure gauge of the oil-water separator reaches 6kg air pressure.

If not, pull out the pressure valve on the oil-water separator upward and turn it clockwise until it reaches 6kg air pressure.

Cylinder damage

When descending, check whether the fuse cannot be opened while being opened.

Replace the cylinder on the fuse that cannot be opened.

Possible causes

Judgment method

Solution

Insufficient hydraulic oil

Check whether the hydraulic oil in the oil drum meets the standard dosage specified in the manual by visual inspection or by using an oil pointer.

Refuel to meet the standard consumption of this model.

Motor reverse

When pressing to rise, observe whether there are bubbles in the hydraulic oil in the oil barrel.

Switch the middle 380V power line connected to the motor with any line on both sides.

The electromagnetic unloading valve core is not closed tightly.

Screw the solenoid unloading valve spool by hand to determine whether it is tightly closed.

Tighten the solenoid unloading valve spool.

Possible causes

Judgment method

Solution

The external power supply is not powered on.

Check whether the external power supply is connected with the power line of the control cabinet (box).

Reconnect the power cord.

Circuit breaker trip

Open the cover plate of the control box and check whether there is a circuit breaker tripping.

Push the switch on again.

Possible causes

Judgment method

Solution

Poor contact of rising button contact.

Press the rising button, and use a multimeter to check whether the wiring at both ends of the button is powered on.

Replace the rising button.

The rising limit is not connected or loose.

Short circuit the limit switch wire, press the rise button, and check whether the machine rises. If it rises, check whether the quick plug connector of the limit switch is loose.

Reconnect the quick connect connector.

Possible causes

Judgment method

Solution

Loose wire rope

Pull the steel wire rope by hand to determine whether it is loose.

Tighten the bolts that fix the steel wire rope.

Friction between column and sliding table.

Check whether the contact part between the column and the sliding table is lubricated.

Add lubricating oil at the inner four corners of the column and test the rise and fall.

The air in the oil cylinder is not exhausted.

Start the lifting machine, raise the sliding table by about 40cm, release the exhaust hole above the oil cylinder without locking, and listen for the sound of exhaust.

Loosen the vent hole until oil is discharged from the vent hole, and then retighten the vent screw.