What Is This Pipe ? AC condensate drain connection

[MikeinLA]

Hello and thank you for allowing me to join your group. I am about to replace a bathroom sink, vanity and plumbing. I took a look underneath to check things out and in addition to the normal water shutoffs, drain pipe, etc, I see a black plastic pipe which leads from above the trap on the drain pipe to a metal pipe that's sticking out of the wall. I can't figure out what it is. I once replaced a powder room vanity and plumbing and it didn't have such a pipe. Does anyone know what it is?

Thanks in advance, Mike

 

[MikeinLA]

Here you go. It's the rubber hose leading from the drain to the wall.

 

[Sponsor]

 

[hj]

Photo was not necessary, since your description was all that was needed. It is your air conditioner's condensate drain connection.

 

[MikeinLA]

Thanks. That makes sense since this is a townhouse and the A/C is on the roof right above this room. Plus I had never seen this kind of pipe before under a sink. Stupid Question: When I disconnect this to change out the sink/vanity, as long as the A/C is not on, should I be fine or prepare for water to come out of the wall pipe? Thanks again.

 

[hj]

It only drains when the A/C is operating and there is humidity in the air.

 

[MikeinLA]

Thanks for your help.