Komatsu PC500LC-10R Shop Manual page 252

COMPONENT PARTS OF HYDRAULIC SYSTEM 10 STRUCTURE AND FUNCTION
5: Suction valve 7: LS shuttle valve
6: Check valve
When the boom is lowered, a regeneration circuit is formed from the cylinder bottom to the cylinder head to in-
crease the oil flow to the cylinder head.
When the cylinder head pressure is higher than the bottom pressure (when dig-
ging, etc.)
Check valve (6) installed to regeneration circuit (C) closes to stop the oil flow from the cylinder bottom to the
cylinder head.
10-158 PC500LC-10R