It has been a few years since I’ve had to read hydraulic schematics, but the load check operates in the return circuit does it not? Supply pressure actuates the load check to allow return flow.
No. The load check operates on the pressure out port.
Example:
When the loader is in a raised position pressure in the lift work circuit is held by the glands on the spool. They block both ports.
If the spool is shifted to further extend the cylinder the glands are repositioned to divert pump flow to the output port and simultaneosly open the return side.
The load check valve keeps the pressure port shut until pump side pressure builds and exceeds the existing pressure if any in the work circuit. At that point pump pressure forces the check valve open and flow goes to the cylinder. This prevents any held load from sagging as the port transitions to open and pressure builds.
Dan