TROUBLESHOOTING GUIDE - EHLTG
Before performing any task, always lower the platform fully to the floor and disconnect the power supply.
Consult the factory for problems at time of installation, or for any problems not addressed below. * Check
the DC notes page for troubleshooting other problems specific to batteries and chargers.
Problem
Power unit doesn’t run when “UP”
button is pressed.
Motor runs, platform doesn’t move.
Power unit not noisy.
Motor hums or pump squeals, but the
platform does not move, or the
platform moves only slowly.
Platform raises, then drifts down.
Spongy or jerky platform movement.
Platform won’t lower
Platform lowers too slowly.
Possible Cause(s):
Transformer fuse is blown.
No supply voltage.
Upper-travel limit switch is engaged
or bad.
Bad control transformer.
Bad motor relay coil.
Motor rotation is wrong (AC-powered
units only).
Pump is failing to build pressure.
See last paragraph, above. Excess
voltage drop to motor, due to power
wire size too small, wire run too long,
or incoming voltage too low.
Motor is “single-phasing”.
Pressure relief opening at full
pressure.
Contamination holding open the
lowering valve or the check valve.
See last paragraph, above.
Excessive air in the hydraulic
cylinders.
Toe guard is actuated.
Toe guard switch, or wire, broken.
Solenoid coil is bad.
Physical blockage of the structure.
Solenoid valve, flow control, or suction
hose screen plugged.
Pinched hose.
Velocity fuse locking (platform only
slowly creeps down). Flow control
spool sticking.
See last paragraph, above.
Action:
Test with meter; replace if bad.
Test with meter. Check fuses,
breakers, and overloads to
determine the cause.
Inspect, test switch. Replace if bad.
Check for 24 VAC; replace if bad.
Test with meter; replace if bad. Verify
the motor runs CW, opposite the shaft
end.
Consult factory.
Same as above.
Check power installation for adequacy.
Check incoming voltage
while motor
is running. Correct problem found.
Determine cause of loss of voltage on
one phase; correct.
Check for structural damage or binding
of the scissor legs, etc. Check for
platform overload condition.
Remove and inspect. Clean per
instructions in “Power Unit
Operation.”
Same as above.
Bleed air per procedure described in
“Power Unit Operation”. Check that
the toe guard bar is
hanging freely. Adjust if necessary.
Inspect visually, check with multimeter.
Repair as needed.
Check with multimeter on diode-check
function. (Reading for ohms will
not provide an accurate test of the
coil.) Inspect for foreign material or
objects that might block the leg set
or its Remove and inspect. Clean
per instructions in “Power Unit
Operation.”
Check pressure, supply, and return
hoses for kinks.
Same as for jerky platform movement.
Remove plug from FC port; push
on flow spool to ensure it is fully
pressed into the cavity. Pull and
clean the spool if necessary. Same
as above.
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