Hydraulics question ?

[Kbeitz]

 

 

I building a crawler from parts. I got down to the Hydraulic control valve and it
has me stumped. I put my air hose to the valve to find out witch output worked
when I pulled the handle back I could not get air to go threw the unit. It's clearly
marked      IN... OUT.... A...B... I tried putting the air in the in port. It would not
take air when the handle was pushed or pulled.. So just for the heck of it I tried
the out port... Everything worked fine this way. My question is .... You can see
a safety relief valve on the input side. Would that stop my low air pressure.
Everything seems to work great putting air in the out port. Could the valve be
marked wrong ?



 

[North River Energy]

Any chance that's a closed center valve?

[snowstorm]

if its a newer valve it could have a closed center sleeve in it. look in the out port. they screw out

[Kbeitz]

This is what makes no sense... The only time it lets air pass is when the valve is in the center.
Moveing it foward of back nothing happens. But if I hook it up backwards it works fine.

[Kbeitz]

Thanks everyone for your help... Found my problem...
This control has a load check.


The load check feature is standard
on all RD-2500 valve models.
The load check will prevent the
fall of a cylinder as the spool is
shifted. It does this by preventing
the back-flow of oil from work port
to inlet. The pump must build up
enough pressure to overcome
the pressure on the work port and
lift the load check poppet. The
load check has nothing to do with
holding a cylinder when the spool.