A vertical 20-in. bore cylinder press with a logic valve setup started drifting down in the neutral position. Unfortunately, many technicians are not familiar with the schematics of how logic valves work.
I always tell people that if they are piloted with a small directional valve then you should treat them like on-off valves. If there is pressure on the top, (spring side) they are held closed and if the top goes back to drain, they will open.
The maintenance technicians did know to remove the covers and check that all the orifices were open and if so, to pull the poppet out and examine it for problems.
Of course, you must also make sure the cylinder piston is not causing the leak by blocking the cap end of the cylinder. A ball valve would work well to determine this; you then energize the circuit to retract the cylinder. If it slightly retracts and stops, the cylinder is fine. If it extends, then there is a piston leak causing the drift. Unfortunately, in this case, they replaced the cylinder thinking it must be the cause.
Can you identify what was the problem? We welcome responses of all kinds directly to Robert Sheaf at rjsheaf@cfc-solar.com or to mgannon@wtwhmedia.com. The solution will be provided next month, in conjunction with our February 2023 issue.
Filed Under: Components Oil Coolers, Trending, Valves & Manifolds
