|catalog std||catalog block||catalog python||3D block|
"custom" means custom part from the custom part dialog that you can open from the dynamic piping tool palette (the button on top)
"3D block" means that you go to the "operator" property of the valve and define an actuator manually, either from the same file or selecting it from another project file.
Catalog blocks for actuators are working in the most cases. If you did already create your python scripts for actuators and now realize that they are good for nothing, please take a look at this article, it will show you how to at least make blocks of it in a quick way:
Please note that if you create a Plant block using PLANTPARTCONVERT, that you do not define a connection, the actuator block doesn't have a connection. The connecting point to the valve is defined by the origin of the AutoCAD block.