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Revision B December 2013
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A.
Clear oil flowing out of fill-hole usually means cylinders
were not fully collapsed when
reservoir was filled.
B.
Foamy oil flowing out of the fill-hole points to the following:
1.
Air is present in the system; that is, cylinders and fluid lines. The response usually
is ''spongy'' and the cylinder moves with a ''jerking'' motion.
2. There is no drop tube or ''down spout'' on the return line so that the oil is not
returning to the bottom of the reservoir.
3. The return oil velocity is excessive; to correct: add a flow control valve to decrease
velocity, increase size of ''down spout'' or add a diffuser.
4. The reservoir is too small to supply the volume of oil required by the cylinders, and
the pump picks up air when the oil level drops below the suction pickup tube.
5. Damage to pump seal (See Pump Section).
C. Water in the oil.
Water can enter the reservoir through the fill-hole if the unit is left outdoors or washed
with high-pressure washers. Protect the unit whenever possible, and change oil
regularly to minimize problems. In cold weather, the water will freeze and the pump
will not work until the ice melts.
4.
Tips and Comments
A.
In most cases the reservoir is made to be mounted either vertically or horizontally and
improper mounting will not allow it to be filled to capacity (See Pump Priming section).
B. On units with a remote reservoir, try to mount it above the pump whenever possible to
“flood” the inlet.
C.
One of the functions of the reservoir is to keep the reservoir in the proper temperature
range. If the reservoir cannot dissipate enough heat, increase the size in order to
bring the oil temperature down to the proper level (See Hydraulic Fluid section).
Filters
Most pump systems have filters which must be cleaned periodically or whenever flow is slow or
sluggish. Some filters may be washed in cleaning solvent and blown dry with compressed air.
Those which cannot be cleaned properly should be replaced. External high-pressure filters may
be added to the system for added protection and ease of cleaning.
