Hydraulic Power Unit Troubleshooting

Up travel

* In = right, out = left

1. No up-start (elevator remains at floor)

Test: Turn adjuster #5 all the way in.

If the elevator now starts upwards, the problem is at solenoid A.

Coil A not energised or voltage too low.

Check electrics. See ¶ below.

Solenoid A tube not screwed down tight.

Tighten solenoid A tube.

Solenoid A: needle AN and seat AS contaminated or damaged.

Clean or change needle and seat.

Adjuster #2 (up acceleration) turned in too far.

Turn out adjuster #2.

Adjuster #1 opened too far (not enough pilot pressure).

Adjust bypass pressure.

Pressure of relief valve S is set too low.

Set relief valve higher (turn in).

Adjuster #8 completely closed (car sits on the buffer).

Turn out adjuster #8. Turn in adjuster #7 completely to close the down valve, then turn out again to required speed.

Bypass flow guide U is too large (slots too wide).

Insert smaller bypass flow guide (see the flow guide chart).

Pump running in the wrong direction.

Check motor direction and install the pump correctly.

The pump connection flange is leaking excessively.

Seal the pump connection.

The pump is undersized, worn or crack in the housing.

Select bigger pump or change pump.

Test: If by turning adjuster #1 with the pump running the pressure does not rise above 5 bar (even with a smaller bypass valve inserted), the problem may be at the pump, at the connection between the pump and the valve or at the pulsation damper, if available.

2. Up-start, but no full speed

Test: Turn adjuster #3 all the way in. If the elevator now travels upwards at full speed, the problem is at solenoid B.

Coil B not energised or voltage too low.

Check electrics. See ¶ below.

Solenoid B tube not screwed down tight.

Tighten solenoid B tube.

Solenoid B: needle AN and seat AS contaminated or damaged.

Clean or change needle and seat.

The pump connection flange is leaking excessively.

Seal the pump connection.

The pump is undersized or worn.

Select bigger pump or change pump.

3. Up-start too hard

Adjuster #1 turned in too far.

Adjust bypass pressure.

Adjuster #2 turned out too far.

Turn in adjuster #2.

Bypass flow guide U too small (slots too narrow).

Insert larger bypass flow guide (see the flow guide chart).

O-Ring UO on bypass flow guide U is leaking.

Change O-Ring (see valve parts detail drawing (Korean))

Star to delta motor switch period is too long.

0.2~0.3 sec. is sufficient.

Excessive friction on the guide rails or in the cylinder head.

Cannot be eliminated through valve adjustment.

4. No deceleration into levelling speed

Coil B does not de-energise.

Check electrics. See ¶ below. Slow down switch is set too high (too late).

Adjuster #3 turned in too far.

Turn out adjuster #3.

O-Ring UO on bypass flow guide U is leaking.

Change O-Ring (see valve parts detail drawing (Korean))

5. Levelling too fast

Adjuster #4 turned out too far.

Turn in adjuster #4 (to about 0.05m/sec levelling speed).

6. Deceleration into levelling speed but overtravel of floor level

Coil A is de-energised too late.

Check electrics. See ¶ below. Change switch position in the shaft.

Adjuster #5 (soft-stop) turned in too far.

Turn out adjuster #5.

Adjuster #1 turned in too far.

Adjust bypass pressure.

Up levelling speed too high.

Turn in adjuster #4 until the lift stops level with the floor or to about 0.05m/sec (recommendation).

7. Bypass pressure not adjustable

Bypass flow guide U too small (slots too narrow).

Insert larger bypass flow guide (see the flow guide chart).

Restriction on the return line.

Enlarge return line.

8. Elevator stops before reaching the floor (no levelling)

Coil A and B reversed.

Swap coil A and B. See ¶ below.

Up levelling speed too slow.

Turn out adjuster #4 until the lift stops level with the floor or to about 0.05m/sec (recommendation).

Middle O-Ring FO of flange 4F is leaking.

Change O-Ring (see valve parts detail drawing (Korean))

Down travel

1. No down start

Coil D not energised or voltage too low.

Check electrics. See ¶ below.

Adjuster #6 turned in too far.

Turn out adjuster #6.

Adjuster #8 turned out too far.

Turn in adjuster #8 cautiously. Attention: Danger of travelling through the floor!

O-Ring UO on down valve X is leaking.

Change O-Ring (see valve parts detail drawing (Korean))

Filter on solenoid D contaminated.

Check filter, clean if necessary.

2. No full speed

Coil C not energised or voltage too low.

Check electrics. See ¶ below.

Adjuster #7 (full speed) turned in too far.

Turn out adjuster #7.

Down valve flow guide X too small (slots too narrow).

Insert larger down valve flow guide (see the flow guide chart).

Filter on solenoid D contaminated.

Check filter, clean if necessary.

3. No down levelling, elevator stops before floor level

Coil C and D reversed.

Swap coil C and D. See ¶ below.

Adjuster #9 turned in too far.

Turn out adjuster #9 (to about 0.05m/sec levelling speed).

Spring 9F in adjuster #9 is broken or down levelling valve Y is blocked.

Clean the down levelling valve or change the spring.

Pressure setting of KS too high.

Turn out adjuster KS.

4. Deceleration into levelling speed, but elevator travels through floor level

Adjuster #8 turned in too far, filter of adjuster #8 clogged, or adjuster #8 damaged.

Turn out adjuster #8 about 1/2 turn. Clean the filter or change adjuster #8.

Down levelling speed is too fast.

Turn in adjuster #9 until the lift stops level with the floor or to about 0.05m/sec (recommendation).

5. No deceleration into levelling speed, elevator travels through floor level

Solenoid C: needle DN and seat DS contaminated or damaged.

Clean or change needle and seat.

Inner O-Ring FO on flange 7F is leaking.

Change O-Ring (see valve parts detail drawing (Korean))

6. Elevator sinks quickly

Solenoid D tube not screwed down tight.

Tighten solenoid D tube.

Adjuster #8 turned in too far.

Turn out adjuster #8 about 1/2 turn.

Damage on down valve X or check valve V.

Check parts and change them if necessary.

7. Elevator sinks slowly due to inner leakage (relevelling)

For possible down leakage points see the "System oil leakage (Korean)" document.

Solenoid D: needle DN and seat DS contaminated or damaged.

Clean or change needle and seat.

O-Ring XO of down valve X is leaking.

Change O-Ring (see valve parts detail drawing (Korean)); when down valve is compensated, replace down valve.

O-Ring VO of check valve V is leaking.

Change check valve (see valve parts detail drawing (Korean))

O-Ring WO of check valve V is leaking.

Change O-Ring (see valve parts detail drawing (Korean))

Inner O-Ring FO in flange 4F is leaking.

Change O-Ring (see valve parts detail drawing (Korean))

O-Ring HO of manual lowering H is leaking.

Change O-Ring HO or change manual lowering.

8. Elevator sinks due to inner leakage of auxiliary equipment

HP: Handpump is leaking.

Seal the hand pump.

HX/MX: Adjuster 8M turned in too far.

Turn out adjuster 8M.

HX/MX: Down valve 9M is leaking; needle DN and seat DS contaminated or damaged.

Clean or change needle and seat.

HX/MX: O-Ring XO of down valve YM is leaking.

Change O-Ring (see valve parts detail drawing (Korean))

HX/MX: Manual lowering is leaking (HX/MX).

Change manual lowering.

Contraction of oil during cooling (especially from 35°C or above).

Consider an oil cooler if hot oil is a problem.

Micro drive MD, door lock valve L10 or L20 are leaking.

When possible isolate and check.

¶ Valves are already adjusted according to available data. Check electrical operation before changing valve settings. To check the operation of the coils, remove the hexagon nut (19 mm). By lifting the coil, the noticeable magnetic force of a live coil can be felt. In addition, the lift function can be changed by lifting off the coils, for example to simulate levelling speeds or to test accelerations and decelerations. If the coil gets too hot, the coil has to be mounted onto the solenoid and the adjustments have to be carried out on normal travels from floor to floor until the coil has cooled down again.