Your pressure network catalog just holds all the information, it doesn't automatically populate your parts list. You need to edit your parts list in your settings or create a new one. When your dialog box comes up after you select edit parts list, go to the pressure pipes tab, right-click the name of the parts list and select add material. This should list all the pipe materials available within the sqlite file that the parts list was created with (you can check this by going to the summary tab and under statistics you will see the file under Catalog Path). If your sqlite file doesn't contain anything other than DI then your gonna have to add them using the content catalog editor or you can create a new parts list with the correct sqlite file selected under set pressure network catalog. Hope this gets you going.
