background image

14

      PRESTO P4 LEVEL LOADER OWNER’S MANUAL

valve has been included for the
protection of all of the workers who
use the unit.

3.   If the motor is not running, check the

electrical plug, the circuit breaker or fuse,
and the wiring to the motor.

4.  The hydraulic oil level may be low. In order to

check the level, lower the unit completely
and unplug the power cord. Remove the rear
cover on the unit. When the platform is
lowered as far as possible, the oil should
be about 1/2’’ to 3/4’’ inch below the top of
the tank. Remove the red plastic plug on
top of the tank. Use a dipstick to check the
oil level.

5.  The motor voltage may be too low. Check

the voltage at the starter when the motor is
under load. The supply voltage should be
within ±10% of the rating.

6.  The tank vent may be plugged.  Before

operating the unit, you must remove the solid
plug from the top of the tank and insert the
red plastic vented plug. The vent line must
be clear.

7.  The suction filter may be clogged. Clean the

suction filter as described in the section on
“Periodic Maintenance.”

8.  A vacuum leak may be allowing air into the

suction line, causing cavitation (loss of
suction) in the pump. Check all fittings in
the suction line, and tighten or replace them
if necessary.

CAUTION!

If cavitation  is allowed to continue,
the pump may be damaged, and may
have to be replaced.

9.   For the platform to raise, the down valve

must be de-energized and closed
completely. Check for a problem with the
wiring to the down valve. Check the solenoid
in the valve with a voltmeter. The valve must
be clean and free to operate. To check this,
remove the solenoid and then the valve. Look

for dirt or metal chips which could block the
valve action. Clean the valve plunger with
kerosene, then blow it clean with
compressed air. The expansion nut which
holds the solenoid should be finger tight
only).

10. If the pump has been changed, the coupling

may not have been installed between the
motor and pump. See the pump assembly
in Fig. 8.

If

 

the

 

platform

 

elevates,

 

but

 

fails

 

to

 

hold

 

a

 

load:

1.   The check valve may be leaking. Dirt on the

valve seat can prevent the valve from
closing fully. The check valve is mounted in
the base of the pump housing, as shown in
Fig. 8. Remove the check valve cap and
inspect the valve for dirt or metal chips
which may be preventing it from closing. You
may be able to restore the seal by lightly
rapping the ball into the seat using a 1/4"
diameter rod and a small hammer.

2.  The down valve may be energized. While

the unit is holding a load, the down valve
should be de-energized and fully closed.
Check the solenoid in the valve with a
voltmeter. The valve must be clean and free
to operate. To check this, remove the
solenoid and then the valve. Look for dirt or
metal chips which could block the valve
action. Clean the valve plunger with
kerosene, then blow it clean with
compressed air. The expansion nut which
holds the solenoid should be finger tight only!

3.  The cylinder may be leaking.  Look for oil on

the cylinder rod and in the vent line. (This
may also occur if the oil tank has been over-
filled.)  If you find much oil in either place,
and the tank is not over-filled, the cylinder
must be repacked. See the section in this
manual on “Repacking the Cylinder.”

If

 

the

 

platform

 

fails

 

to

 

lower:

1.   The sensor and reflector for the photo eye

toe guard are mounted at the front of the
unit, near the floor level. There may be
something blocking the beam of the photo

Summary of Contents for P4

Page 1: ...Model Number ___________________ Serial _________________________ Date Placed in Service _____________ IMPORTANT READ CAREFULLY BEFORE INSTALLINGOR OPERATINGLIFT Part orders are subject to a 50 miminum charge May 2006 ...

Page 2: ...l settings The instructions included in this manual are not necessarily all inclusive because Presto Lifts cannot anticipate all conceivable or unique situations In the interest of safety please read this whole manual carefully Please understand the material in the manual before you install use or service the P4 unit If you have any questions about the instructions in this manual please contact yo...

Page 3: ...NTENANCE AND TROUBLESHOOTING 10 Hazards 10 Routine Periodic Maintenance 11 Troubleshooting Check List 12 Repacking the Cylinder 15 Adjusting the Chain Tension 15 Ordering Replacement Parts 16 LIST OF FIGURES Fig 1 Safety labels 5 Fig 2 Pinch points 6 Fig 3 Load the unit correctly 7 Fig 4 Electrical diagram 8 Fig 5 Hydraulic diagram 9 Fig 6 Parts identification Front view 12 Fig 7 Parts identificat...

Page 4: ... TAKEN Therefore throughout this manual Presto has identified certain hazards which may occur in the use of the P4 Level Loader unit and provided appropriate INSTRUCTIONS or PRECAUTIONS which should be taken to avoid these hazards In some cases Presto has also pointed out the CONSEQUENCES which may occur if Presto s instructions or precautions are not followed Presto uses the following system of i...

Page 5: ...ion where the cord can reach an outlet easily without stretching the cord tightly 5 Move the unit into position supporting the platform of the unit Place the unit on a firm level surface CAUTION If you place the unit on a surface which is not firm or level the unit may shift as it operates You may be hurt or the unit or load may be damaged 6 The unit may be operated without bolting the frame to th...

Page 6: ...lumber or other materials which might get in the way of the unit as it raises or lowers 2 Warn others to stay away from the unit Operate the unit through its full range of travel The unit should rise smoothly with a quiet humming sound and lower smoothly and quietly Raise and lower the unit a few times to check the lifting action WARNING As the platform moves up and clown pinch points are created ...

Page 7: ...R The unit uses a power supply of 115 Volts AC This voltage can kill you DON T WORK WITH THE ELECTRICAL PARTS UNLESS YOU ARE A QUALIFIED ELECTRICIAN WARNING As you operate this lift follow these rules Do not put your hands or feet under the lift platform Do not work under the lift platform without installing the safety pins See Fig 6 and the section on Maintenance Do not stand sit or ride on the l...

Page 8: ... t try to lift a load that exceeds the maximum rating If you do not follow these rules the unit may fail suddenly Someone may be hurt or the unit and load may be damaged The unit is designed so it can lift the rated load if the load center is placed over the center of the platform The load center should be 24 or 61 cm from the rear of the platform If the load is placed offcenter near the front of ...

Page 9: ...ise the platform and Down to lower it If the unit does not operate right away unplug the power cord and call a qualified maintenance worker WARNING If you hear a squealing noise from the pump the pressure relief valve is operating DON T CONTINUE TO USE THE UNIT The pump will overheat very quickly and may be permanently damaged The relief valve is included to protect the machine operators DO NOT CH...

Page 10: ...y of 115 Volts AC This voltage can kill you DON T WORK ON THE ELECTRICAL PARTS UNLESS YOU ARE A QUALIFIED ELECTRICIAN WARNINGS As the unit moves up and down pinch points are formed as shown in Fig 2 KEEP HANDS FEET AND LOOSE CLOTHING AWAY FROM THESE PINCH POINTS If your hand or arm or a part of your clothing is caught you may be hurt Before performing any maintenance on the unit lower the platform...

Page 11: ...cal guides for the rollers on the rear of the unit Check all of the hydraulic fittings and hoses and tighten the connections if necessary Sometimes the fittings can be worked loose by the vibrations from the power unit WARNING If a hydraulic fitting becomes loose or if a hydraulic hose breaks the hydraulic fluid may escape from the system under pressure If the platform is raised when this happens ...

Page 12: ...ise CAUTION If the platform will not raise do not continue to hold the Up button for more than 2 or 3 seconds You may damage the pump 1 The sensor and reflector are mounted at the front of the unit near the floor level There may be something blocking the beam of the photo eye toe guard The reflector may need to be cleaned or replaced 2 The load may be too heavy Check the actual weight of the load ...

Page 13: ...cap Retainer ring Relief valve adjusting screw Check valve cap O ring Check valve spring Check valve ball Outer spring Inner spring Relief valve poppet Coupling pump to motor Gasket Down valve plunger Down valve strainer Down valve solenoid Nut Fig 8 Pump ...

Page 14: ... the valve Look for dirt or metal chips which could block the valve action Clean the valve plunger with kerosene then blow it clean with compressed air The expansion nut which holds the solenoid should be finger tight only 10 If the pump has been changed the coupling may not have been installed between the motor and pump See the pump assembly in Fig 8 If the platform elevates but fails to hold a l...

Page 15: ...ader unit may use several different types of cylinders To order a repacking kit and receive repacking instructions please call the Presto Lifts Parts Department at 800 343 9322 When ordering specify the model number and serial number of the unit Adjusting the Chain Tension It is very important that the lifting chain be tensioned correctly As the chain is used it will tend to stretch a bit Over tim...

Page 16: ...warranty Freight prepaid and invoice for small parcel shipments except parts covered by warranty Parts replaced under warranty are on a charge credit basis We will invoice you when we ship the replacement part then credit you when you return the worn or damaged part Presto Parts Department 21 Park Street Attleboro MA 02703 Telephone 800 343 9322 FAX 888 788 6496 Email service PrestoLifts com www P...

Page 17: ...re order Consult Customer Svc 2 Custom engineered modified lifts No Returns PARTS Standard parts may be returned with a 20 restocking fee Modified or custom engineered parts are not returnable Unfortunately due to potentially concealed damage all sales of electrical assemblies are final QUALITY ISSUES Should you feel there is a quality problem please contact the seller to ask questions and gather ...

Page 18: ...hirty 30 days from the effective date of the RMA to have the merchandise arrive freight prepaid at Presto Lift Inc Returns from locations other than the Continental US Canada and Mexico must be shipped within the thirty 30 day period to arrive Free On Board FOB at Presto Lift Inc as soon as practical If a customer believes Presto Lift Inc s merchandise is defective freight will be reimbursed to th...

Page 19: ...PRESTO P4 LEVEL LOADER OWNER S MANUAL 19 ...

Page 20: ...RMA number The shipping charge to return the component to the buyer is the responsibility of Presto Lifts Inc This limited warranty does not cover labor expense for removal or reinstallation of components after thirty days This limited warranty shall not cover among other things damages resulting from foreign matter or water failure to provide reasonable and necessary maintenance and if appli cabl...

Reviews: