How To Select The Pipe Diameter for The Piping in A Custom Hydraulic System? How to select the pipe diameter for the piping in a custom hydraulic system? How should the pipe diameters be selected in a custom hydraulic system? The specific situation needs to be analyzed in detail because it depends on whether the distance between the pump station and the actuator is long or not. Does the speed of the actuator need to be strictly controlled? Also, some hydraulic systems operate continuously while others work for a short period and then rest for a long time. We can choose the size and thickness of the pipes based on the working pressure of the hydraulic system and the flow rate passing through it, and consider the material of the pipes. All these details can be found in the hydraulic system manual.