[djseal]

New bathroom sink backs up halfway, quickly drains, repeat.. no overflow in this sink,

[speedball1]

Do you have a vessel sink? Tom

[LuckyRockstar]

Actually I just installed a new sink today in my bathroom & it's now taking forever to drain. (Didn't have that problem with the other sink). I ran drano down it thinking it was clogged because that's what commercials tell us to do. Still really slow draining. The water goes down w/ a slow gulping... kinda like emptying a 2 liter bottle upside down in a sink. Vent problem? And yes, mine is a new vessel bowl-style sink. Is that a common problem w/ those?

[speedball1]

Djseal and Rockstar, Since you both share the same complaint I'm leaving both posts in the same thread. Yes it's a vent problem and yes it's a common complaint. Since vessel sinks have no overflow to vent through they take a special drain made for them,(see images) Ifyou Have anything else installed then you have found your problem.
You may also vent your sink by Vent the drain by adding copper tubing out of the drain just below the vessel, through the wall, to a height exceeding the height of the vessel.
This solution provides a safe air admittance route to the drain pipe on the vessel side of the P-trap where it is usually provided for by sinks with overflows. The copper tubing will never overflow in the wall because it is higher than the height of the vessel. The vessel will always overflow first in the unlikely case of an undetected clog in the P-trap, the same risk that exists if there is no air admittance tube.
If the homeowner is afraid to drill a hole in the wall, the air admittance tube can terminate as high as possible within the cabinet, or the tube can be run through a hole in the countertop behind the vessel.
This solution allows the continued use of the attractive and unobtrusive grid drains in the vessel.
With the air admittance tube connected the vessel drains very, very quickly.
I think that this solves the only potential drawback to using these beautiful vessels.
Good luck, Tom

[LuckyRockstar]

Thanks Speedball. You're 100 correct. I have the grid drain you show on your pictures. That actually came w/ the faucet that matched the vessel bowl so you'd think it would be correct. Since reading your post I asked my plumber that installed it about the vent & he said that normally drains have a vent hole in the side of it that vent up to the overflow hole but this drain kit didn't come w/ a vent hole in it. (My vessel actually has an overflow hole). So he said I should drill a couple small holes in the drain pipe to coincide with the overflow drain channel. He said that should fix it. If he knew that, wonder why he didn't just do that to begin with. Thanks!