OPERATING THE MACHINE SECONDARY RELIEF PRESSURE ADJUSTMENT When attaching the breaker other than the NPK, it is necessary to install the secondary relief valve in line. For this purpose, the boom piping for the attachment is provided with a part to which the secondary relief valve is connected. Pressure is set to A when shipped from HITACHI. Two methods are available to measure the pressure. Measure the pressure as follows. 1. Measuring the pressure at the relief valve : (1) Attach a pressure gauge to the pressure gauge connection port (see the figure below) (2) Close the stop valves at the arm end. Depress the attachment pedal to pressure the line.
After completing piping, reset this pressure to the specified level of each breaker. (3) Adjust the pressure to 1 to 1.5MPa (10 to 15 kgf/cm 2 ) higher the setting pressure. Adjust the pressure as follows : 1. Attach the pressure gauge to the pressure gauge port. 2. Loosen the lock nut, then gradually turn the pressure- adjust screw clockwise to increase the pressure, or coun- terclockwise to reduce the pressure. One turn of the screw changes about 4.9MPa (50 kgf/ cm2) in pressure. 3. After adjusting the pressure, make sure to tighten the lock nut. PRESSURE INCERESE PRESSURE DECREASE PRESSURE-ADJUST BOLT (WIDETH ACROSS FLAT: 14) (WIDETH ACROSS FLAT:
14) LOCK NUT PRESSURE GAUGE CONNECTION PORT (PT 1/4) 2. Measuring the pressure at the arm end. M107-05-005 (1) Remove the attachment connection horse and con- nect a pressure gauge to the connection fitting at the arm end. (2) Adjust the pressure to the setting pressure. 5-20 Model Set Pressure A ZAXIS400R-3, 400LCH-3 19.6MPa (200 kgf/cm2)