Komatsu ecot3 PC300LC-8 Shop Manual page 175

10 Structure, function and maintenance standard
4. When abnormally high pressure is generated
q If abnormally high pressure is generated in the
boom cylinder bottom circuit, the pressurized
oil in port (B) pushes check valve (6) open,
then safety valve (3) operates.
PC300, 350-8
q If arm drift prevention valve (optional) is
installed to the arm cylinder head circuit, the
boom cylinder bottom circuit pressure force or
arm cylinder head circuit pressure force,
whichever having higher pressurized oil,
pushes check valve (6) or (6A) open to actuate
safety valve (3).
SEN01994-01
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