I've just finished the replacement of some under slab ABS rough plumbing, placed a test ball in the main drain at the test tee, and all seemed to be sealed with 10' of head. I bought the ball type tester with the chain because it was considerably cheaper than the balloon type that threads into the tee. I'm only going to use it once after all.
1. Where does the test ball go for the test, before or after the test tee? I placed it after, filled the system and then stuck a old piece of hose down the vent and siphoned the water out to a sewer clean out in the yard. All very unsanitary. Still had a little water left when I opened the tee cap, but worked out well in the end.
2. One of the ABS clean threaded cleanout plugs leaked even after I screwed it in all the way. What do you use to seal the threads so the cap can be removable?
1. You put the plug on the upstream side of the test tee with the chain and loop outside the tee so it cannot get washed down the pipe when it deflates, whether intentionally or by accident.
2. After the test, you deflate the ball and the water flows past it down the drain.
3. Sometimes you CANNOT make the plug watertight. I either put a rubber test cap OVER the plug and tighten it to the tee's opening, or divert the leaking water away from the pipes so the inspector can tell that the pipe itself is not causeing the wetness.