16
13. Trouble shooting:
If there is slightly leaking oil at the piston that does not
have to mean that there is a damaged seal, it may be
remaining oil from the piston which has gathered during
the operation of the cylinder in the upper chamber.This is
absolutely irrelevant to the function of the cylinder.
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Pump does not built up a pressure:
•
Check if the release valve handle is closed
•
Check oil level of the reservoir
•
Check if ventilation plug of reservoir is opened
•
Check if there is dirt in ball seats
•
Discouple the cylinder and build up a slight pressure
against the male coupling
Pump builds up pressure, however, the hydraulic
cylinder does not advance:
First check oil level of the reservoir. If the pump is working
correctly and the pressure is being built up, then:
•
the force to operate the hand lever of the hand pump
will increase
•
the hydraulic hoses will stiffen
If possible, use a pressure gauges during test procedure.
A temporary decoupling of all actuators facilitates the
checking process.
If the pump builds up pressure, however, the hydraulic
cylinder still does not advance:
•
Check couplers for complete closure
•
Check hydraulic system for any leakage (fittings, seals,
etc.)
•
Check hydraulic cylinder for leakage
•
Check if ventilation plug of reservoir is opened correctly
•
For double acting cylinders you should check if a
damaged seal causes leaking of oil from one chamber
into the other oil chamber of the cylinder
Therefore the piston has to be advanced completly
and the hydraulic hose piston sided has to be discoupled,
a pressure gauges has to be mounted at the discoupled
port of the cylinder and the advancing side of the
cylinder has to pressurized. If the gauges is indicating
a pressure, the seal of the advancing side is damaged.
Hydraulic cylinder does not retract:
For single acting cylinders with spring return, one hose
connection
•
Check if couplings are closed completly, otherwise the
oil flow is cut off.
•
Check if cylinder is equipped with spring return (YLL,
YG, YLG and YFG do have gravity return - to be
retracted by external weight)
For double acting cylinders, two hose connections
Check if the oil flow in retracting direction is closed, e.g.
a not completly closed coupler
System does not hold the pressure:
Hydraulic pump actually builds up pressure, but
pressure drops again quickly:
•
Release valve (hand wheel) closed properly?
•
Check hydraulic system and cylinder for any leakage.
•
Repair of pump is required. (Dirt in ball seat?)
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Air venting:
All reservoirs of Yale hand pumps are equipped with an
"air venting / filler plug".
The dvantage is, that the capacity of the oil reservoir can
be used completly, the pumps have an excellent suction
perfomance.
Important:
Be sure to close the air vent plug of the reservoir after use.
This avoids any possible loss of hydraulic oil in case the
hand pump is turned over.
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General Operating Instructions for
Yale-Hydraulic Cylinders and Hand Pumps
Summary of Contents for Yale RPYS-1215
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