20
Condition
Cause
Remedy
The motor rotates
without increasing the
pressure at all or
properly.
The set pressure for the high-
pressure safety valve is lower
than the operating pressure.
Set the pressure for the high-pressure
safety valve to 73 MPa. When using
the pump at a low pressure, set a
value 3 to 5 MPa higher than the
operating pressure.
The high-pressure pump is
damaged. If the pump is
making an unusual noise and
the pressure pulses, it is
damaged.
Ask the sales agent for repair.
Abnormality of internal
components of the tank
• Loosening of fasteners,
dropping of components
• Damage to components
Ask the sales agent for repair.
The directional control valve
is out of order.
• The valve is flawed.
• The seal is broken.
Ask the sales agent for repair.
The directional control
valve (ESW-4H or ESL-
4S) does not work.
The spool is immobilized
because of a flaw or
hydraulic locking.
Ask the sales agent for repair.
The coil is damaged because
of wrong voltage.
Replace the coil with one appropriate
for the voltage.
The coil is broken or
improperly connected.
Check continuity of the coil and
connection. If the coil is broken,
replace it.
The diode is damaged.
A rectifier is used for AC/DC
conversion. Replace the rectifier
(terminal parts).
The cylinder piston does
not extend or retract
quickly.
The bag nut at the coupler is
loose, resulting in a narrow
passage.
Tighten the bag nut thoroughly .
The pipe resistance is too
high to allow the low-
pressure oil to be discharged.
Replace the pipe with a thicker one.
The pressure does not
rise neither when the
cylinder extends nor
retracts.
The cylinder piston seal is
damaged.
Ask the sales agent for repair.
The oil temperature
increases intensely.
The pump is used too often.
The ambient temperature is
too high.
Install an oil cooler to keep the oil
temperature not higher than 60°C.
Oil is leaking inside the
pump.
Ask the sales agent for repair.
