Testing/troubleshooting a UnifiedTM Hydraulic Jacking Machine
Follow
these instructions to perform the actions necessary to find out what is right
and wrong with the operation of a UnifiedTM
jacking machine.
The
first thing to do is to inspect the oil. It
should be golden hydraulic oil, without any reddish ATF, diesel fuel, kerosene
or any other additive in it. Start
the engine and let it warm up. Open
ALL of the “unified needle valves
(the left hand valves).”
Close ALL of the “outlet needle valves”
(the right hand valves)
and the “helper jack outlet” valves. Check
all the hose lines and fittings for any leaks.
The main control valve lever operates either up and down, or side to
side. Move it
both ways briefly to find out moving the lever in which direction causes
the numbered meter rod visible in the sight glass on the side of the main tank
to advance or retract.
Move
the main control valve lever in the direction needed to get the meter rod to
zero and hold it there until the zero shows.
Keep holding the lever over and the pressure on one of the large gauges
in the upper right of the panel should reach between 5500 and just over 6000 PSI.
If this pressure cannot be generated on the gauge, listen for a rushing
noise coming from the valve itself. This
indicates that the main control valve relief valve is not not set properly.
The segment of the main control valve that controls this operation can
also be faulty. If the pressure does
not hold when the lever is released to the center position, check for any leaks
at the hoses and fittings behind the panel.
Let the machine set under pressure for five to ten minutes and check for
any leaks and fix them before continuing.
Restart
the machine and build pressure up
to 5000 PSI,
then close ALL of the “unified needle valves”
(the left hand valves).
If pressure drops off on a jack pressure gauge when the unified needle
valve is closed, suspect a bad circuit relief valve, or (much less likely) worn
internal cylinder seals. With all of
the “unified needle valves” closed tight, move the main control valve lever
to move the meter rod forward (away from zero).
Pressure should rise on all of the jack pressure gauges, and on one of
the two gauges in the upper right of the panel.
You should be able to get at least as much pressure on the gauges as you
reached before. If not, then the
segment of the main control valve that controls jacking may be faulty.
If the pressure is higher than was reached before, the other working
segment of the main control valve may be bad.
The main control valve is subject to wear from dirty oil over time, and
will suffer premature wear if the oil is not kept clean.
Pressure
on all of the gauges that show pressure should reach 5500 to 6000 PSI.
Release the main control valve lever, and the pressure should hold on all
of the gauges. If pressure falls on
a jack pressure gauge, suspect a faulty relief valve.
These also suffer wear from dirty oil.
A slow loss of pressure means a very minor leak, just a few drops of oil
per minute. If all of the gauges
lose pressure at about the same rate, including the large “main cylinder”
gauge, suspect worn main cylinder seals.
Close the needle valve between the two large gauges.
If pressure continues to drop, then the main control valve segment is
bad. If the pressure stops dropping,
then the main cylinder seals are worn out.
The key to keeping a UnifiedTM jacking machine alive and functioning for decades is to change the oil twice a year, start and operate the machine weekly while it is stored to maintain lubrication of the seals and cylinders by circulating the oil, keep the oil clean by checking the filter screen at oil changes, and minimizing the machine’s exposure to dirt.
By
following the above procedures, you can check the health of a UnifiedTM
jacking machine.