Komatsu PC200-8M0 Shop Manual page 188

SEN06120-00
In boom "LOWER" operation
q When operating boom "LOWER", the pilot pressure from the PPC valve pushes pilot piston (2).
q The pressurized oil of the boom cylinder bottom flows from orifice (c) to drain port (T) through orifice (a)
and chamber (b).
q Chamber (b) inside poppet and drain port (T) are interconnected, and the pressure of chamber (b)
drops.
As the pressure of chamber (b) becomes less than the pressure of port (B), poppet (5) opens.
q
q As poppet (5) opens, the pressurized oil from port (B) flows to port (A) and then flows to the control
valve.
46
10-402
402 Hydraulic system, Part 2
Functions and operation by valve
PC200, 200LC, 220, 220LC-8M0