Could air cause this issue???

[LD1]

Went back through the whole thread in order to try to figure out just what is going on.

Before I started the D.W. for the first time with the new valve/log lift...it raised the lift but then stopped...the cylinder would not move in either direction...likewise with the splitter cylinder...it is like the system is locked up...activating either of the spools the cylinders move a fraction and stop...and not necessarily in the direction they are supposed to according to the way the valve is engaged...

When you said this, I need some clarification. Are the cylinders going to the end of their travel and THEN locking up? Or are they locking up no matter what position they are in? Fully retracted, somewhere in the middle? Or just once fully extended they will no longer retract?

Both the cylinders work like they are supposed with the (original) single spool valve...but when I install the new (Prince Wolverine) two spool valve...

When hooking up the old single spool, I assume you are operating one single cylinder at a time? And they both then work normally?

Now...after putting a gauge in a working circuit...I initially get 2500 in one direction but only get 2000 in the other...and the machine bogs a bit...adjusting the PRV seems to have no effect on these pressures...

another thing...when I first start the D.W....it moves a cylinder normally for a very short time then it locks up...again it acts like the fluid is not being able to return when the valve is engaged but testing with forced air it works fine...
Would/could the PRV be causing something like this...

When you put a pressure gauge in a working circuit, how did you do this? Did you remove a hose and test the port? or did you TEE it in? If you Tee'd it in, you should NOT have made much pressure, as it would not require much force to move the cylinder. If you just removed the hose and put the gauge in the port, those numbers seem okay.

When you say "cylinder moves normally for a very short time then locks up". Just what is the definition of short time? Are we talking 2-3"? or are we talking 1/8-1/4"?

Also, are these OPEN center valves that you keep refering to? or are they tandem center valves? (I would think you would want tandem center at least on the log lift).

A tandem center valve opens pressure to tank but blocks off A and B ports on the valve. This is how most loader valves are.
A true open center opens ALL ports to tank. If it truly were an open center valve, when in neutral (again A and B ports open to tank) the log lift would bleed down because it dont isolate the working ports like a tandem valve.

We WILL get to the bottom of this.

 

[J_J]

Apparently we do not have the whole story.

If you have a DA valve connected to a single DA cyl, and you push the lever, the cyl is going to move. If it does not, suspect the QD. or get rid of the QD's.

Just make sure the two spool ports are connected to the same cyl, such as A1 connected to cyl port A1, and Bl port connected to cyl port 2.

If this valve is the last valve in the flow path, you can run the OUT port to tank. PB port with no adapter should be plugged.

If this valve is inline with other valves, then the PB adapter should be installed and feeding the flow path in series and the log splitter valve OUT port will go to tank.

 

[LD1]

I would also like to see a pic of how the lines are attached to the DW.

I know you said you are 100% sure that the hoses are hooked up correct. And the pictures on the valve do show the inlet and outlet correct (red tape inlet is on the side of the casting with the PRV). But that dont mean its right at the DW.

What you are describing is exactly what would happen if you were to try to supply flow in the return port and have the inlet hooked to tank. Because there is a check valve on the pressure port that will allow flow INTO the valve, but NOT out. Its to protect other things in the circuit from flow going the wrong direction when the pump is off, and gravity is acting as your pump.

So if the inlet and return lines are crossed on the DW, with the open center valve, fluid passes through valve (only reversed, flow going from tank port and out the inlet port and back to the DW). But as soon as you open a lever, a passage is opened to allow flow (from tank port) into the cylinder, but wont be able to return due to the check valve in the pressure port.

The single spool may or may not have a check valve. But the diagram of the 2-spool certainly shows one.

 

[pmsmechanic]

I just want to learn something here.

 

[LD1]

See if this will help.

If you have inlet and tank reversed, with both levers in neurtal there is no issue. Fluid can flow freely from tank to port or port to tank. It dont care which way it flows



The way the valve should work...



And if you reverse the pressure and tank lines


Notice there is no issue supplying the fluid to the working port and on to the cylinder even if it is being supplied from the tank side of the valve. The problem becomes that check valve (circled in green) that prevents fluid from exiting via the pressure port.

This describes your symptoms to a TEE.

 

[/pine]

See if this will help.

If you have inlet and tank reversed, with both levers in neurtal there is no issue. Fluid can flow freely from tank to port or port to tank. It dont care which way it flows

View attachment 453316

The way the valve should work...

View attachment 453317

And if you reverse the pressure and tank lines
View attachment 453318

Notice there is no issue supplying the fluid to the working port and on to the cylinder even if it is being supplied from the tank side of the valve. The problem becomes that check valve (circled in green) that prevents fluid from exiting via the pressure port.

This describes your symptoms to a TEE.

Yes I agree that is what seems to be happening...BUT...the splitter works great with the original single spool valve and the connections to the DW as they are...I have considered reversing them just to see what happens...!

When you said this, I need some clarification. Are the cylinders going to the end of their travel and THEN locking up? Or are they locking up no matter what position they are in? Fully retracted, somewhere in the middle? Or just once fully extended they will no longer retract?

When a lever is first engaged a cylinder will move a few inches then locks...will not move in either direction...

When hooking up the old single spool, I assume you are operating one single cylinder at a time? And they both then work normally?

Yes

Also, are these OPEN center valves that you keep refering to? or are they tandem center valves? (I would think you would want tandem center at least on the log lift).

I refer to them as OC because fluid passes between the IN and out ports when no spools are engaged...I'm ignorant of the difference with "tandem center valves"...

Thanks for the time and replies....I will try to get some more pictures posted later today...

 

[LD1]

Yes I agree that is what seems to be happening...BUT...the splitter works great with the original single spool valve and the connections to the DW as they are...I have considered reversing them just to see what happens...!

As I said, that single spool valve may not have the check valve in there.

If the two spool valve didnt have that check valve on the pressure side, you would be none-the-wiser and everything would be working even if the P and T were reversed. Only thing is the adjustable PRV valve wouldnt work and you would be operating at whatever the PRV of the DW is set to.

Have you actually stuck the supply and/or return hoses into a bucket, and fired up the DW and see which one has oil coming out?

 

[oldnslo]

/pine,
Presuming the DW has a built in relief valve can you just take the hose that you have labeled as pressure and dead head into a gauge. If you see system pressure then your connections are correct, if not then you may have them switched because everything that LD1 stated is correct. A single spool valve may not have the load checks but if you run the valves with P & T switched for very long there is a very good chance that you will damage the valve seals and or crack the valve casting. Most Tank ports are only good for a couple hunderd PSI.

 

[/pine]

Again, thanks for the time and perspectives...After I post these pictures I will try and make some short videos of what is happening...

...that single spool valve may not have the check valve in there...

This is the top of the original single spool...it appears to be just a plug where a PRV would normally be...?


Here are the connections to the DW, (the open bottom QD is Power Beyond) the return line goes to the bottom of the tank:


Here are the QDs that connect the original hoses (they were connected to the original valve on the DW) to the 20's hoses:


This is the working end:


And a couple of of overall views:




I will reread recent replies soon and try to answer anything I have missed...

 

[/pine]

I have absolutely confirmed that the pressure (red tape) line is pumping fluid....

 

[LD1]

Well if it is indeed pressure, it is clearly returning with valve in neutral.....otherwise the DW would really be bogging down.

So pressure to valve and return from valve is okay. Just wont return when valve is shifted....HMMM

the internal passages to return the fluid from the cylinder to the tank hook direct to the same passage that flows to tank when valve is in neutral. Are you absolutely sure there is no PB plug in there and you are hooked to the CORRECT tank port on the valve?

May cost you a little fluid and be messy, but what happens if you UNHOOK the tank line from the valve, use a bungee cord to pull a lever, and fire up the DW?

(dont want to fire the DW and then try to run over and open the valve. Cause being open center you will loose a lot of fluid in that time period.)

It will either

1. not flow any fluid and cylinder be locked as it is now
2. Pour out oil expelled from the cylinder as it moves

 

[LD1]

Where you located BTW?

I am sure it isnt even remotely close to me, but this has me so intrigued I would travel a bit just to see this in person and help solve the issue.

 

[/pine]

Well if it is indeed pressure, it is clearly returning with valve in neutral.....otherwise the DW would really be bogging down.

So pressure to valve and return from valve is okay. Just wont return when valve is shifted....HMMM

the internal passages to return the fluid from the cylinder to the tank hook direct to the same passage that flows to tank when valve is in neutral. Are you absolutely sure there is no PB plug in there and you are hooked to the CORRECT tank port on the valve?

May cost you a little fluid and be messy, but what happens if you UNHOOK the tank line from the valve, use a bungee cord to pull a lever, and fire up the DW?

(dont want to fire the DW and then try to run over and open the valve. Cause being open center you will loose a lot of fluid in that time period.)

It will either

1. not flow any fluid and cylinder be locked as it is now
2. Pour out oil expelled from the cylinder as it moves

The tank port on the valves are open from IN to OUT (with spools centered)...I have checked but if a PB plug was installed this should not be?

I can pull the tank line off one of the two spools and see what happens following your suggestion...but I think if there was any return (with a lever engaged) everything would be working??

Without much else left to try...I am going to see if I can use the PB and backhoe return ports rather than the auxiliary lines I'm having the issue with...I will have to order some fittings etc...so I will have some time to continue troubleshooting...

FWIW...The DW is a complicated machine...it has both open and closed center circuits

I'm in the very corner of N.E. GA... just a few miles from both NC and SC...

 

[LD1]

The tank port on the valves are open from IN to OUT (with spools centered)...I have checked but if a PB plug was installed this should not be?

I can pull the tank line off one of the two spools and see what happens following your suggestion...but I think if there was any return (with a lever engaged) everything would be working??

Without much else left to try...I am going to see if I can use the PB and backhoe return ports rather than the auxiliary lines I'm having the issue with...I will have to order some fittings etc...so I will have some time to continue troubleshooting...

FWIW...The DW is a complicated machine...it has both open and closed center circuits

I'm in the very corner of N.E. GA... just a few miles from both NC and SC...

If you pull the line and crack a valve as I suggested, you are confirming 100% weather the problem is the valve (no oil coming out), or something else with the setup or DW (oil would come out and cylinder move).

Valves get tricky if you dont follow the instructions to the letter. Multiple places to hook a tank return line and/or PB plug. Adding the PB cartridge and using another tank port to have two outlets (if using PB), if not using PB, most joystick or two spool valves have 2 or 3 places that a return line "can" be hooked in. Knowing which one to hook in and which ones to block off depends on setup. (open center, closed center, PB). Easy to get confused.

 

[/pine]

...(open center, closed center, PB). Easy to get confused.

I thought I understood how the valves work as far as the "OC, CC and PB goes...in the case of a valve with PB...it can be used as either OC or CC...previously I have plumbed and installed three other Prince (Wolverine Series) MB valves...a single spool using PB and the PB port on my loader for a grapple...and both a single and double for three rear remotes using the PB on one to supply the other...I had no issues with the valves or setting them up...this experience does have me confused to say the least...!...but then again some things are best learned by being initially confused...

I set up the two spool valves as OC because the original is OC....but I don't know that the original single spool has the check valves that are shown on the schematic...I do not have a schematic for the Cross two spool valve or the original...

Here is another part of the puzzle that may have been overlooked I think I only mentioned it once...

When I first quit thinking it could be air and realized it was more of a problem...I thought possibly the spools may have been installed backwards or something...I had no idea....!...this is after checking, rechecking and checking again that I had the plumbing correct and the QD seats...

So to test the valve (this is the new Prince two spool)...I set it up with a clear hose between the two working ports on one of the spools...(the valve still had some oil in it)...ran another clear hose to a catch can and charged the pressure port with air...with the spools centered it discharged air/fluid out the Tank port to the catch can...when I engaged the spool...air/fluid moved from one working port to the other and vise versa with the spool engaged the opposite way...all the time air fluid was moving between the working ports...it was still discharging through the OUT/Tank port into the catch can....exactly like it is supposed to...granted this is just low pressure air so I am not sure what any check valves or the PRV may be doing??? the DW is 2500 and the docs say the Prince valve was set at 2000...but I was reading 2500 when it is locked up and I don't hear the pressure relief valve kicking in.... could thios be a clue?

 

[LD1]

Try this,

Put air to the P port and PUSH the lever. Make note of which port gets air coming out.

Now put air in the work port that did NOT get the air coming out, and move the lever same direction. Make sure it comes out tank port. Do the same thing for the other work port and PULL the lever this time. Confirm that air is coming out tank port.

 

[/pine]

Apparently we do not have the whole story.

If you have a DA valve connected to a single DA cyl, and you push the lever, the cyl is going to move. If it does not, suspect the QD. or get rid of the QD's.

Just make sure the two spool ports are connected to the same cyl, such as A1 connected to cyl port A1, and Bl port connected to cyl port 2.

If this valve is the last valve in the flow path, you can run the OUT port to tank. PB port with no adapter should be plugged.

If this valve is inline with other valves, then the PB adapter should be installed and feeding the flow path in series and the log splitter valve OUT port will go to tank.

J_J....I was hoping you would add your thoughts (all replies are truly appreciated, all have been helpful)...this is a mystery...!

If you have a DA valve connected to a single DA cyl, and you push the lever, the cyl is going to move. If it does not, suspect the QD. or get rid of the QD's

The DA cyl.(s) move a bit then lock up...and the hoses pulse when the spool is engaged...we have determined beyond reasonable doubt that fluid is flowing through the valve but not being allowed to return when a spool is activated...Have been using the same four QD (with the single spool valve) since July with no issues

 

[/pine]

Try this,

Put air to the P port and PUSH the lever. Make note of which port gets air coming out.

Now put air in the work port that did NOT get the air coming out, and move the lever same direction. Make sure it comes out tank port. Do the same thing for the other work port and PULL the lever this time. Confirm that air is coming out tank port.

I assume you mean on the original single spool?

 

[LD1]

No. Do it in the two spool. Basically air test the return to rank circuit

 

[Leejohn]

It might be a good ideal to step back and look everything over real good. Make yourself a drawing of the plumbing with one of the 2 spool valves hooked up and not guess while making up the drawing. If it looks ok to you then post your drawing.