Gresen 3 Spool Valve

IAtractorKid · Mar 3, 2013

Hey guys! Have a Gresen 3 spool valve on my loader and have
a few questions about it. It worked fine on my SH with M&W
live hydraulics but will be going on my 400 with a 17.2gpm
Prince PTO pump this summer. Valve has 2703 stamped in the
top and 1084 on the bottom of the built in pressure relief valve.
Questions:

How do I know if its open or closed center and what does that
mean?

What are the pressure relief valves factory set at and is there
any way to tell where it is now?

First handle does not spring back to center like the other two,
how is that fixed?

Lastly, when plumbing to the PTO pump, will 3/4 pressure and
return lines be sufficient or should I run 1"? I think my loader
manual calls for 1" but both pump and valve only have 3/4
fittings.

Thanks for the help!!

Roger in Iowa · Mar 3, 2013

First handle may have "float" position so it will not spring back. Looks like the caps on the far side of the valve (away from handle) are different. Under the caps are pieces that cause the spring back or locate into float.

HTH.

pete 23 · Mar 3, 2013

There are so many different valves out there hard to say for sure. But, I feel the valve should have a centering spring on all three, (spring back to center). If it has float it should have a seperate detent in end cap to hold it in the float positon but spring to center when pulled back out of float. Open center valve you can blow into inlet right on through to outlet with all valves centered. Closed the flow will be blocked when blowing into inlet. As far as relief valve pressure, hard to tell, might be around 1500 to 1800 psi. Would have to put a gauge in any work port and dead head that port or T into input port and dead head any valve. Far as 3/4 inch pipe fitting they will handle that flow no problem.

IH fan · Mar 3, 2013

(reply to post at 14:39:33 03/03/13)

I'd say the set-up on the left side of the valve is the system relief valve andit looks like it's adjustable, probably only within a narrow range, most likey can be varied 500-1000 psi, for example between 1000 or 1500 and 2000psi. Only way to tell for sure is to deadhead a valve, operate that valve fully one way and read a pressure guage on the inlet. If it had a pre-set relief, it would look more like a hex plug with the model # and pressure stamped in it.
3/4" or -12 should be okay for a 17 gpm pressure line, but your low pressure return line should be 1" or -16 so it doesn't have too much back pressure. Pete is right on the valve... it should have a detent set-up on a valve spool if it has a float position.

Janicholson · Mar 3, 2013

If it worked on the H, it is open center. It means that the pressure remains at near zero in the supply line from the pump Because the valve is open to the return line to the reservoir. A constant circulation. A closed center system (and simi closed demand systems are more complex and will not work on an H. I think it will be fine on the 400. Jim

Gresen 3 Spool Valve

IAtractorKid

Member

Roger in Iowa

Well-known Member

pete 23

Well-known Member

IH fan

Well-known Member

Janicholson

Well-known Member

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