Please help with DWV Air Pressure Test

I've installed DWV pipe for a laundry room and bathroom addition and want to perform an air test before I close up the floor. I purchased a Cherne test ball, pump, 10 foot air hose extension, and all the plugs to plug up trap and vent stubs. I had assumed that I would just insert the test plug and pump it up and there would be a hole in the top of the plug to let air out to pressurize the pipe and therefore the pressure of the pump would be the pressure of the closed system.

However (as many of you probably know) this is not the case. The test ball does plug the pipe, but it doesn't pressurize the system.

I can't find anything simple to buy that allows me to pressurize the closed system and read the pressure. Do plumbers have to make them? I can imagine how one is made with a rubber test cap and 1/4" pipe to attach a an air gauge and to attach a compressor, but I'm not confident I can make one that won't leak. Somebody's got to make these, right??

I guess one solution is to put a hole in the cherne test ball so that it can pressurize the system, but I hate to 'break' a $25 ball if there's a better way.

Any help greatly appreciated.

Jeff

Where I’m at we plug everything and head to the roof with a garden hose and fill the system by the vent system. There will be some air trapped in the system witch is fine. By code you have to add 5 feet to the top of the vent for this test but is not often done. Our inspectors want it filled at least 12 hours before the inspection.

As you know a test plug will only plug the pipe. We do not do the air test where I’m at so I don’t know how there done.

test ball

Since it takes about 30-40 psi to seal a test ball that is the pressure which would be inside the pipe, if you did it the way you mentioned, assuming you could find some way to seal the ball until the air pressure started to increase. We install a device of some kind, there are a multitude of ways to do it, connected to one of the drain connections or cleanout threads, and inject the test, water or air, that way.

Find someone with a Kuhlman Gauge and reduce a pipe down to 3/8" FIP and hook the gauge up, it will show you almost instantly if you have a leak.

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