Sink Installation

[MMB13]

I recently purchased a small ranch with a house that was mostly completed. It's lacking some of the finishing work and I'm trying to do it myself to save money.

I need to install the sink counters and plumbing and in one sink I don't know what to make of this:

I didn't take the best picture angle, but there is a pipe coming out of the wall through the back of the cabinet and connected to a T joint, which is open at the top, and then goes down and out through the drain pipe.

I don't know where the pipe is flowing from, but my guess is overflow from the hot water heater in an attic above.

I am most definitely not a plumber and don't know what to do with this so that I can install the sink.

Suggestions?

 

[frodo]

go find your ac unit. i bet you it is the condensate drain from th unit

when you hook up your sink drain. turn the t- stat to no cool

tjhen use a y -branch tail piece below the basket strainer before the p trapp

glue a barb fitting on the pipe as it exists the wall, use a 5/8 id/1'' od black rubber hose to hook up the drain to y branch