chk for backpressure in return...filter clogged kinkeed return line etc...
DA or SA cyl's?
edit:
since cylinder ports are connected to return when on float, it is possible that back pressure can lift cylinder. It all depend on...
1. size of back pressure psi...
2. size of cylinder rod if DA cylinder, bore size if SA cylinder in inch...
3. size of load on cylinder in lbs
each 50psi back pressure on return, can make a 1" diam SA cylinder push 39 lbs.....
each 50psi back pressure on return, can make a 2" diam SA cylinder push 157 lbs.....
each 50psi back pressure on return, can make a 3" diam SA cylinder push 353 lbs.....
If cylinder is DA, diameters have to apply on the cylinder rod, which determines the differential area between capped and rod side....
Since SA and DA cylinders are a pretty common subject, I'll make this comment....
Some SA cylinders can look like a DA cylinder with two ports, but rod side port is always connected to return or straight to tank. Even if rod side is connected to CV port, there can be a spool SA valve spool.
SA or DA is easiest determined by if there is power down or not.
