Adding a sink drain to a main drain

Dec 10, 2007 3 Replies

I need to add a 2" sink drain to a main vertical 3" drain. I will need to remove a section of the main 3" drain and replace it with a PVC fitting to accept the 2" sink drain. Should a Wye or a sanitary T be used?


Use a WYE or a TEE/WYE.

A san TEE is used where the stack above the TEE will be used as the vent for the new fixture trap, which is unlikely the case here.

Jim

Thanks for the response, but not sure what you mean here. The PVC fitting I plan to install has a 3" opening on top, a 3" opening on the bottom, and a 2" branch off the side. The main stack (where I want to tap into) is from floor to ceiling and indeed does vent to the roof. Are you saying the main stack is not likely vented? The san TEE is an easier fit, would require fewer fittings than the wye, and no relocating studs in the wall.

If the stack has fixtures on the floors above, then it cannot be used for venting purposes where you are connecting in.

While a San TEE may fit better for your project, it really isn't correct although it may work OK.

Jim

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