I'm an owner-builder, getting ready for a close-in inspection which includes plugging and testing the DWV system for a new bathroom. I have a standard 3" test ball that I have used as a test plug in the past, but that was always with a standard sanitary tee. The plumber that I hired used a Y fitting for the cleanout, and the test ball won't work. If I plug the outlet to the Y, then the water will just come through the cleanout. And I can't plug the cleanout separately in this case, because of the chain attached to the test ball.
How do I plug up the DWV system for inspection, when the cleanout uses a standard ABS 45% Y hub?