PVG 32 AND 120 PROBLEM 2

[BEMPE16524]

Hi Guys,

I have a problem with a PVG 120 valve.
The schematic is shown in attachment (marked as DCV-1).

When i operate other functions (using PVG32) besides 'Luff'(using PVG120), the luff cylinder is pushed out.
Regardless whether i operate the lever up or down, the luff cylinder will be pushed to the same direction.

Anyone had same problem before? Currently we dismantle the PVG120 and do some servicing.



R.Efendy

 

[Jacc]

Check your backpressure on the T port of the PVG. Maybe a quick coupler to the HPU is not opening fully, either not fully connected or just malfunctioning.
If there is a lot of backpressure, running any other function except LUFF will raise the pressure in the T gallery which will push oil out through both A and B ports of the LUFF section.
If both A and B are pressurized at the same time the rod will extend because "the big piston area "wins" over the smaller rod area" or more scientifically, it becomes a single acting cylinder with the piston rod as the effective area. The pressure will pilot both counterbalance valves open.