320C and 322C Excavators Attachment Hydraulic System – System 5: Relief Valve (Line) – Test and Adjust – Attachment Control Valve

Use the following information in order to work in the service mode.




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(1) Up key

(2) Down key

(3) Left key

(4) Right key

(5) Set key

(6) Menu key

(7) Cancel key

(8) OK key

Test for the Line Relief Valve (Attachment Control Valve)

Note: A temporary setting of main relief valve is required before any line relief valve pressure setting is adjusted. Refer to the temporary setting of main relief valve in Testing and Adjusting, “Relief Valve (Main) – Test and Adjust” for the machine.

  1. Position the machine on level ground and stop the engine.
  1. Release the pressure in the hydraulic system. Refer to Testing and Adjusting, “Hydraulic System Pressure – Release” for the machine.



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    Pump compartment for the 320C and the 322C

    (26) Pressure tap (idler pump)

    (27) Pressure tap (drive pump)

    (37) Pressure tap (power shift)





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    Pump compartment for the 325C

    (26) Pressure tap (idler pump)

    (27) Pressure tap (drive pump)

    (37) Pressure tap (power shift)

  1. Connect a 60000 kPa (8700 psi) pressure gauge to pressure tap (27) . Connect a 6000 kPa (870 psi) pressure gauge to pressure tap (37) . This is used to monitor power shift pressure.

    Note: Refer to figure 2 for the 320C and the 322C machines.

    Note: Refer to figure 3 for the 325C machines.

  1. Start the engine.
  1. Place the machine controls at the following settings: engine speed dial 10 and AEC switch OFF. Refer to Testing and Adjusting, “Engine Performance – Test – Engine Speed” for the machine for engine rpm settings.
  1. Set the pilot pressure to the specifications in Testing and Adjusting, “Relief Valve (Pilot) – Test and Adjust” for the machine.
  1. Increase the hydraulic oil temperature to 55° ± 5°C (131° ± 9°F).
  1. Set the main relief valve to specifications. Refer to Testing and Adjusting, “Relief Valve (Main) – Test and Adjust” for the machine.
  1. Calibrate the power shift pressure. Refer to Testing and Adjusting, “Proportional Reducing Valve – Calibrate (Power Shift)” for the Engine and Pump Control System.
  1. Start Service Mode and input a fixed power shift pressure of 2900 kPa (420 psi).
    1. Press menu key (6) .

      Note: If more than thirty seconds pass between pushing the keys on the keypad, the menu mode will be cancelled and the previous display will be restored to the message display.

    1. Press down key (2) in order to highlight the menu item “SERVICE OPTIONS” on the message display. Press OK key (8) .
    1. Input the password “FFF2”. Press left key (3) or right key (4) in order to change the position of the flashing character. Press up key (1) or press down key (2) in order to change the value of the flashing character. Press OK key (8) after the correct password is displayed.
    1. Press down key (2) in order to highlight the menu item “SWITCH STATUS” on the message display.
    1. Press right key (4) repeatedly until “DEVICE TEST” appears on the message display.
    1. Press down key (2) in order to move down one line on the message display.
    1. Press right key (4) until the “PS PRV – FIXED” appears on the message display.
    1. Press down key (2) .
    1. Press OK key (8) . The display on line 4 of the message display will now change to a numeric value. These characters represent an approximate power shift pressure (kPa).
    1. Press left key (3) or right key (4) in order to increase or decrease the desired numeric value that is displayed on line 4 of the message display to “2900”. Pressing left key (3) one time decreases the power shift pressure 10 kPa (1.5 psi). Pressing right key (4) one time increases the power shift pressure 10 kPa (1.5 psi).

      Note: The value for power shift pressure on the monitor may not always match the pressure reading on the pressure gauge. Adjust the value on the monitor until the desired power shift pressure is attained on the pressure gauge that is connected to the pressure tap for power shift pressure. The actual power shift pressure must be 2900 kPa (420 psi) on the pressure gauge.

    Note: To prevent a change in power shift pressure during the adjustment of the line relief valve for the attachment control valve, do not turn the engine start switch to the OFF position.

    Note: Refer to Service Manual, RENR3814, “Engine and Pump Control System” for additional information on Service Mode.

  1. The pressure setting for the top line relief valve and for the bottom line relief valve for the attachment control valve is 36800 ± 1500 kPa (5340 ± 220 psi).



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Line relief valve (typical example)

(14) Locknut

(15) Adjustment screw

Note: After relief valve adjustments, cancel Service Mode.

Note: Return the main relief valve pressure to the specified setting after testing and adjusting any line relief valve. Refer to Testing and Adjusting, “Relief Valve (Main) – Test and Adjust” for the machine for the main relief valve pressure setting.

Note: To prevent oil flow to the work tool during this testing and adjusting procedure, close the stop valves in the lines for the work tool.

Adjustment of the Line Relief Valve (Attachment Control Valve)

  1. To adjust the line relief valve pressure setting of the upper work tool, push the foot pedal for the work tool FORWARD. Hold the foot pedal in this position.
  1. Check the pressure in the work tool at pressure tap (2) .
  1. Return the foot pedal for the work tool to the NEUTRAL position.
  1. Compare the pressure reading to the specification 36800 ± 1470 kPa (5340 ± 220 psi). If the pressure reading is within the specification, no further adjustment is necessary. If the pressure reading is not within the specification, then proceed to Step 5.
  1. Loosen locknut (14) on the upper line relief valve for the work tool. Turn adjustment screw (15) until the pressure gauge reading at pressure tap (27) is 36800 ± 1470 kPa (5340 ± 220 psi).
  1. To adjust the line relief valve pressure setting of the lower work tool, push the foot pedal for the work tool BACKWARD. Hold the foot pedal in this position.
  1. Check the pressure in the work tool at pressure tap (27) .
  1. Return the foot pedal for the work tool to the NEUTRAL position.
  1. Compare the pressure reading to the specification 36800 ± 1470 kPa (5350 ± 215 psi). If the pressure reading is within the specification, no further adjustment is necessary. If the pressure reading is not within the specification, then proceed to Step 10.
  1. Loosen locknut (14) on the lower line relief valve for the work tool. Turn adjustment screw (15) until the pressure gauge reading at pressure tap (27) is 36800 ± 1470 kPa (5350 ± 215 psi).
  1. After completion of line relief valve adjustment, tighten locknut (14) .

Note: Turning adjustment screw (15) clockwise increases the pressure. Turning adjustment screw (15) counterclockwise decreases the pressure.

Note: Always make final pressure adjustment on pressure rise.

Note: After relief valve adjustments, cancel Service Mode.

Note: Return the main relief valve pressure to the specified setting after testing and adjusting any line relief valve. Refer to Testing and Adjusting, “Relief Valve (Main) – Test and Adjust” for the machine for the main relief valve pressure setting.