Troubleshooting - Presto Lifts Dock Lift Series Owner's Manual

7

Troubleshooting

PROBLEM
Lift will not raise
Presto Lifts
POSSIBLE CAUSE
Load too heavy
Power unit not receiving
power
Hand controls may be
malfunctioning or may not be
receiving power
Motor contactor may be
malfunctioning
Motor may be turning in wrong
direction
Hydraulic Fluid low
Lift has reached it upper limit
Motor voltage too low
Tank vent plugged
Suction filter is clogged
Vacuum leak in the suction
line
Down valve may be energized Check for voltage to down valve solenoid,
Missing coupling between
motor and pump (if applicable)
Pressure relief valve is
activated
External Hydraulic leak
Make sure the load does not exceed the rated
capacity.
Verify that the power unit is receiving power.
Section 8 Electrical on page 31.
Verify that the controls are receiving power
and are functioning correctly.
Electrical on page 31.
Verify motor contactor is functioning.
Section 8 Electrical on page 31.
Swap any two phases of the motor power leads.
With lift in fully lowered position the fluid level
should be approximately 3/4" from the top of the
tank.
Upper limit switch may need to be adjusted.
Supply voltage must be ± 10% of the rated
voltage at the motor terminals.
Make sure vent plug on hydraulic tank is
installed and not blocked.
Clean suction filter.
Check all fittings and hoses for damage or loose
connections.
should be no voltage present.
Check to make sure the coupling between the
pump and motor has been installed. (Machines
manufactured before September 2012).
If there is a loud squealing noise the pressure
relief valve may be activated. Contact
Presto Lifts Customer Service for further
assistance.
Inspect all hoses, connections, and cylinders for
leaks.
29
CHECK
See Section 8
See
PDL Dock Lift Manual
See