Load Sense Compensator; Main Relief Valve; Load Sense Relief Valve; Turntable Swing Relief Valve - JLG 600SC Service And Maintenance Manual

SECTION 5 - BASIC HYDRAULICS INFORMATION & SCHEMATICS
5.6 MAIN VALVE BLOCK PRESSURE SETTING
PROCEDURE
Refer to Figure 5-68. Main Control Valve Block.
COLD TEMPERATURES HAVE A SIGNIFICANT IMPACT ON PRESSURE READINGS.
JLG INDUSTRIES INC. RECOMMENDS OPERATING THE MACHINE UNTIL THE
HYDRAULIC SYSTEM HAS WARMED TO NORMAL OPERATING TEMPERATURES
PRIOR TO CHECKING PRESSURES. JLG INDUSTRIES INC. ALSO RECOMMENDS
THE USE OF A CALIBRATED GAUGE. PRESSURE READINGS ARE ACCEPTABLE IF
THEY ARE WITHIN ± 5% OF SPECIFIED PRESSURES.

Load Sense Compensator

1. Install a pressure gauge at port MP1 of the main control
valve capable of reading pressures up to 1000 psi 
(70 bar).
2. Start the Engine.
3. Adjust Load Sense Compensator (1) to 400 - 450 psi 
(27.5 - 31 bar). Turn adjuster clockwise to increase or
counterclockwise to decrease pressure.

Main Relief Valve

1. Install a pressure gauge at port MP1 of the main control
valve capable of reading pressures up to 5000 psi 
(345 bar).
2. Activate telescope in and hold.
3. Adjust main relief valve (2) to 3350 - 3400 psi 
(231 - 234.5 bar). Turn adjuster clockwise to increase or
counterclockwise to decrease pressure.
4. If the pressure will not rise to 3350 psi, the load sense
relief valve will have to increase. Locate the load sense
relief valve. Increase this setting by 1 turn clockwise. Go
back to the main relief valve and increase until the cor-
rect pressure is achieved.
5-80

Load Sense Relief Valve

1. Install a pressure gauge at port MJ of the main control
valve capable of reading pressures up to 5000 psi 
(345 bar).
2. Activate telescope in and hold.
3. Adjust load sense relief valve (3) to 3200 - 3250 psi 
(220.6 - 224.1 bar). Turn adjuster clockwise to increase or
counterclockwise to decrease pressure.

Turntable Swing Relief Valve

1. Install a pressure gauge at port MJ of the main control
valve.
2. The turntable should be locked in place with the turnta-
ble lock pin. Activate swing right.
3. Adjust Relief Valve (8) to 1700 - 1750 psi 
(117 - 120.5 bar).
4. One adjustment will take care of both directions. Swing
left will be approximately 50 - 100 psi (3.5 - 7 bar) lower.
Turn adjuster clockwise to increase pressure or counter-
clockwise to decrease pressure.
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