Converting a double acting valve for use with single acting cylinder?

J_J · Apr 10, 2014

Thanks, your knowledge and description of the valve is appreciated.

This valve is a first for me.

It works pretty much like I said, does it not..

No body else does what they did as far as using the T port for the selection for the closed center or standard valve., and no one uses the N symbol to designate a port.

The T port and the N port share the same cavity. They chose to confuse the situation.

Like I said before, use air to determine the flow.

As far as Plugging A and use B as the work port is fine. Either work port will work. You are simple shifting a spool.

If using this valve in an open center hyd system, either the T port or the N port can be used for the OUT fluid.

As far as back pressure, the say 700 psi. That is usually stated for the tank pressure, and they usually refer to the problem with exceeding the value, is that the seals will be damaged.

PB ports have always been able to handle high pressure.

They don't show a carry over/PB port, but if this is the last valve in the system, you don't need one.

If you need PB, then I would not use this valve.

Use air to verify all functions.

Elder Massey · Apr 10, 2014

Right.. "they" chose to confuse the issues. A new right out of the box control valve with the T port blocked with an otherwise unidentified plug should be enough to raise red flags to anyone. This man, and several others that have asked the same questions about the tank port being blocked, combined with an again unidentified "N" port, with or without an instruction sheet, is utter nonsense. The plug had to be removed to identify it as a closed center plug. This man had to call several stores and could not get a straight answer. If something does not come with a schematic diagram of the circuit for that particular device, or it is not available anywhere else, then I personally believe that end users are senselessly put at risk. In essence, that is all that I am saying or will say.

I don't need someone distributor's lawyers breathing down my throat. Personally, when so much time has to be devoted to basically troubleshooting a brand new control valve, my opinion is that it should not be on the market and I will speculate that this is why these controls are on eBay for fifty bucks. Kind of akin to buying Chinese dogfood.

I checked mine for use as a 4 way. He should verify what the supposed "instruction" sheet says for 3 way use. While I know that I could use it as a 4 way my thoughts were about whoever has to deal with it in the future. My brand new "convertible control" is in my scrap pile behind my workshop where it will stay.

glastron23 · Apr 10, 2014

Elder.. these are not that bad of a valve.. just a little bothersome to get info on them.. the N port is a tank port on the 3/4 valves. On a 4 way only valve it would be used as a Power beyond out port.
The 3/4 valves require that the plug 14 be installed in the T port for a 3 way valve as it allows the A port(via a drilled passage) to bleed to tank when you retract the SA cylinder. The spool will open the pump flow to the A port and this needs to go to tank to prevent the hydraulic oil from dead heading in the unused A port.
When you change it to a 4 way valve you install plug 13 in the T port that plugs the A port drilled passage and allows the A port to then direct fluid to the DA cylinder. All pump flow then exits the N port back to tank.