A vented relief valve is used to unload the pump flow through the relief valve at very minimum pressure setting to avoid over heating your hydraulic system.
This is the best way to learn how you can interchange any hydraulic pump you have for a better alternative.
Often people need to interchange their hydraulic pumps from existing system to a different pump that can offer better delivery time, pricing, or simply because their old pump hard to find or obsolete.
These are different examples of system applications for hydraulic check valves. Check valves are a very important component for proper work of hydraulic equipment as shown in these examples.
It seems to be a common problem that the hydraulic pump isn’t “lifting pressure”. Well, assuming you have your relief valve all the way closed, you might need to check the pressure setting on your pressure compensated pump.
Video below is a quick reference on how to set a pressure compensated control for a variable displacement pump.