Komatsu PC220-7 issue

[rockfall]

Will do the time cycle test. You forgot to tell me about the safety-suction valve thing. What is its function in the control valve. Will playing with it increase efficiency of the machine?

 

[John C.]

The safety suction valve is just another name for a circuit relief. The suction part of the relief refers to an anti-cavitation function to prevent a vacuum happening on a function. For the CLSS systems the pumps destroke at a set pressure and the safety suctions usually only open when an outside force is applied mechanically to an implement. An example might be when a heavy rock falls on the bucket and tries to force the bucket closed and the stick down. The safety suction would relieve the circuit and allow the oil to flow out of one side of the cylinder and the suction part on the other side of the cylinder function would open to tank and allow oil to be drawn into the other side. In order to test them you would have to raise the pump setting above the setting of the valve or remove the valve and use a porto power and a mounting jig.

 

[Godwin Shoko]

Got it. John can you search for me where it is exactly located in dash 7 because I have searched the back side of the control valve a lot for this valve but couldnt find it. Is it next to the back pressure valve somewhere?

This is how it looks like from the back.View attachment 195985

May you kindly provide me with the whole pc 220 manual if you ve got....