Why can't I temporarily block this drain?

[softly]

Hello,

I have a basement drain that I would like to temporarily block. The lowest part of the drain is 2 inches in diameter, the middle part (about 3 inches long) is 3 inches in diameter and the top part (about 3 inches long) is 4 inches in diameter.

I have tried using a "3 in. Gripper Plastic Mechanical Test Plug", but there is a spot on the side where water seems to flow around it. I tried wrapping the rubber part in duct tape to make it thicker, but that didn't help either.

I have tried a 3 inch Cherne test ball plug, but water finds its way around that too!

Does anyone have any idea why I can't seem to temporarily block this drain?

 

[hj]

The most likely cause would be that the material is too 'rough' for the plugs to conform to their surfaces.

 

[Sponsor]

 

[JohnfrWhipple]

Your test plugs should not be "Blocking" the drain but rather the drain line.

Try using a 2" test plug with a short extension hose. Then you will find things easier.