operator. If the labels are worn or missing, or have been painted over, REPLACE THEM before releasing the lift for operation. Fig. 1 shows the safety markings on this unit.
Routine Periodic Maintenance
Every month:
•Remove the plate on the rear of the unit and check the mechanical parts. Inspect the leaf- type chain which lifts the platform. Check for signs of wear. If the machine is operated in a very dusty environment, you may have to wipe off the dust.
•Check the bolts which anchor the ends of the chain. The chain should be tight, and each bolt should be locked in place.
•Check the level and appearance of the hydraulic fluid. In order to check the level, lower the unit completely and unplug the power cord. Remove the rear cover on the unit. Remove the red plastic vent plug on top of the hydraulic tank, and use a dipstick to check the oil level. When the platform is fully lowered, the oil should be about 1/2’’ to 3/4’’ inch below the top of the tank. Add oil if necessary. Change the oil if it has darkened, or feels gritty or sticky.
CAUTION!
It is important to use hydraulic fluid with the correct grade and properties. See the hydraulic oil specification in Fig. 10 of this manual.
Every six months or 500 hours of operation, whichever comes first:
•Lubricate the lifting chain lightly with spray lube or SAE 30 mineral oil.
•Lubricate the bushing inside the sheave or pulley which supports the upper part of the chain.
•Apply a light coat of grease to the vertical 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, it can drop quickly. Someone may be hurt, or the unit or load may be damaged. To avoid this problem, inspect all of the hydraulic hoses and fittings regularly, and replace them if they are worn or damaged.
•The clear plastic vent line and the cylinder rod should be free of hydraulic fluid. If you find much fluid in either place, the cylinder seals may be leaking. (It is also possible the tank may be
•Lower the platform and disassemble the down valve as shown in Fig. 8. Blow the valve plunger clean with compressed air. Reassemble the valve and reinstall it.
•Drain and discard the hydraulic fluid. The suction filter is in the tank, at the point where the suction line runs out to the pump. Unscrew the hydraulic line, then remove the filter. Blow the filter clean with compressed air. Reinstall the filter in the tank and reassemble the hydraulic line.
•Refill the tank with new hydraulic fluid.
CAUTION!
If you continue to use fluid after it has “worn out,” the moving parts in the system will wear more quickly.
•Be sure all of the warning labels are in position and legible. See Fig. 1. THE WARNING LABELS ARE INTENDED TO PROTECT YOUR WORKERS. If the labels are missing, or if they have been painted over, replace them.
PRESTO P4 LEVEL LOADER OWNER’S MANUAL 11
