Rev. 6/30/2020
DCR-880, MANUAL
Copyright 2020 Vestil Manufacturing Corp. Page 20 of 25
to the reservoir rather than pushing it into the cylinder. This pressure relief mechanism prevents damage to the
hydraulic system.
To lower the carriage, press the
DOWN
button. This energizes the lowering solenoid valve coil, which unseats the
poppet valve and allows oil to return to the reservoir from the cylinder through the pressure-compensated flow control
valve. Releasing the
DOWN
button de-energizes the solenoid and closes the valve poppet. The poppet valve and
check valve together prevent oil from returning to the reservoir and cause the cylinders to stop retracting. The carriage
will maintain its position until another command is received.
LOWERING SOLENOID VALVE
The lowering valve might occasionally need to be cleaned. See “Troubleshooting” on
. Before working on
any
part of the hydraulic system, always lower the carriage.
1. Remove the cover from the power unit.
2. Identify the lowering valve (port LL in the manifold) and remove it.
3. Use a thin tool to press the poppet in (from the bottom of the valve) and open the valve.
4. Repeat several times while immersing the valve in kerosene or mineral spirits.
5. Blow compressed air through the valve while holding it open as described in step 3.
6. Inspect the O-rings and the PTFE washer (polytetrafluoroethylene). If either component is damaged, replace it.
7. Reinstall the valve. The valve should be tightened to approximately 20 ft.-Ib. of torque.
VELOCITY FUSE
There is a brass velocity fuse with a stainless steel spring in the base of the cylinder. This safety feature reduces
the possibility of personal injury and damage to the DCR (or load) if there is a sudden loss of hydraulic pressure. If a
fitting leaks or a hose is punctured, the platform lowers more rapidly. If the rate of descent exceeds the preset speed
of the velocity fuse, the fuse closes. While the fuse is shut oil cannot flow. The carriage remains stationary until
pressure is reestablished.
The velocity fuse might activate although no failure occurs, if, for instance, air enters the hydraulic system. To be
able to raise or lower the carriage requires resetting the velocity fuse. To reset the fuse, activate the pump by jogging
the
UP
button. Immediately after resetting the velocity fuse, lower the carriage and remove the drum. Then, cycle the
carriage by raising the carriage all the way up and back down. Do this several times to purge air from the system.
BLEEDING AIR FROM THE HYDRAULIC CIRCUIT
If the carriage descends very slowly or not at all, air probably is trapped in the hydraulic circuit and must be bled
from the system. To bleed air from the hydraulic circuit, follow these directions.
1.) Lower the carriage. If applicable, also disengage the drum.
2.) A “bleeder” screw is located at the top of the cylinder Loosen the bleeder screw by 1/4 to 1/2 turn to allow
trapped air to escape. Jog the motor to push air out of the system.
3.) When the cylinder is free of air, only clear hydraulic fluid will flow from the bleeder screw opening. At that point,
retighten the bleeder screw.
USING THE BATTERY CHARGER (DC UNITS ONLY)
Working on lead-acid batteries is dangerous. Batteries contain sulfuric acid and produce explosive
gases. A battery explosion could result in loss of eyesight or serious burns.
•
DO NOT smoke near the battery or expose the battery to a spark or flame.
•
ONLY charge batteries
in
dry, well-ventilated
locations.
•
DO NOT lay metallic items, like tools, on top of a
b
attery
•
NEVER touch both terminals simultaneously! Remove personal jewelry items such as rings and watches.
•
Always have plenty of fresh water and soap nearby in case contact with battery acid occurs.
•
Operating the battery with low voltage can cause premature motor contact failure.
•
The charger is equipped with an external ground wire (small green wire). During installation the charger must be
grounded to the equipment. Be sure this wire is always connected to the chassis, frame, or other metallic surface
considered to be ground.
•
Remove accumulated deposits on the terminals and confirm that all battery connections are sound.
•
Replace defective electrical cords and wires immediately.
•
DO NOT use the charger if the flanged inlet is damaged.
•
DO NOT connect the charger to a damaged extension cord.
Every DC powered drum carrier is equipped with an onboard battery charger with a flanged electrical inlet. The inlet
is mounted through the cover/housing of the power unit. The user must provide a 3-prong charging cord appropriate
for the line and motor voltages.
The charger is current limited and will not exceed its rated output even if loads are placed on the battery while it is
charging. The charger fuse will blow if it is connected in reverse polarity. To charge the battery:
