18
10 Adjusting the High-pressure Safety Valve
The high-pressure safety valve is factory-set to 73 MPa. To readjust it, perform the following
steps:
(1) Stop the motor and loosen the lever of the directional control valve.
(2) Remove the hexagon socket head cap screw (92)
and turn the adjustment screw (22) inside the oil
tank counterclockwise using a screw driver to loosen
it.
(3) Disconnect the high pressure hose (or the fitting)
from the discharge port and set a hexagon socket
head plug.
(4) Set the pressure for the pressure switch to 75 MPa.
(5) Activate the motor.
(6) Tighten the lever of the directional control valve.
(7) While checking the display of the pressure switch,
gradually turn the adjustment screw clockwise to
increase the pressure until it becomes 3 to 5 MPa
higher than the operating pressure.
(8) Loosen the lever of the directional control valve.
(9) Repeat shifting of the lever of the directional control
valve a few times to increase the pressure and check that the set pressure is achieved.
(10) Reset the set pressure for the pressure switch to the operating pressure.
(11) Remove the plug from the discharge port and connect the high pressure hose (or the
fitting).
(12) Set a hexagon socket head cap screw (92).
*
Do not readjust the pressure to a value higher than 73 MPa.
*
Set the pressure for the pressure switch 3 to 5 MPa lower than the setting for the high-
pressure safety valve to prevent the safety valve from operating continuously.
*
Make sure to wrap sealing tape around the hexagon socket head plug and taper pipe
thread of the high-pressure hose before screwing them. See "How to wrap sealing tape" on
Page 10.
*
A setting lower than or equal to 20 MPa loosens the adjustment screw or causes other
problems. If any malfunction occurs, contact the sales agent.
*
Ensure that position the suction filter below the oil level so that the pump will not take in
air.
Structural drawing of high-pressure safety
valve
