Hyundai 35DS-7 Operation Manual page 155

(2) Inlet section
Unloading valve piston
At spool neutral position, oil flows from pump line to tank line through unloading valve piston.
Also unloading valve piston controls flow rate work section.
Maximum pressure of the system controls by primary relief valve.
LS
T
PS
T
Rst
LS
P
6-11
PS
P
T
Primary relief valve
R1
Max work port pressure line
D357MCV22