Help with non-draining lavatory sink

[Darrin]

My bathroom sink doesn't drain properly without "burping it". The odd part is - the sink seemed to drain fine the first few years we lived here, but now it doesn't. I have taken apart the piping to check for clogs or otherwise obvious issues and all is clear. The Toilet & Tub/Shower both drain just fine.

A few weeks ago, in an attempt to correct this issue, I replaced the under cabinet piping arrangement with what is pictured below (mainly to add an air admittance valve similar to what had been used under our kitchen sink). The original under-lavatory piping was previously a simple trap then went straight down through floor. Yes, i wasn't keen on using the flex/accordian adapter, but it seemed the only means i could find to connect the riser plumbing to the pipe coming up through floor.

Any suggestions/advice would be greatly appreciated!

 

[Reach4]

Does your lavatory have overflow holes? Those can serve as a vent. In that case, maybe that path is blocked somehow. Try closing the stopper. Fill the bowl to above the holes. Does water go down the holes?

If you lift the stopper totally out, is the flow good?

 

[Sponsor]

 

[Darrin]

No overflow holes in sink. Also, as far as I can see, the stopper doesn’t come out. A decorative top to the stopper does unscrew (has rubber back that helps seal), but doing so doesn’t allow the guts to lift out.

When I was replacing the plumbing with what you see in photos, I tested the sink with the pipe below the trap off; water flowed very freely so I’m quite sure there’s nothing blocking.

 

[Plumber69]

Why not show a video of the problem

 

[Darrin]

I did!!!

 

[Reach4]

No overflow holes in sink. Also, as far as I can see, the stopper doesn’t come out. A decorative top to the stopper does unscrew (has rubber back that helps seal), but doing so doesn’t allow the guts to lift out.

Try adjusting the actuator linkage so that the stopper opens farther. I don't see the linkage in your photo connecting to the rod into the drain.

 

[Terry]

How does it drain without the stopper?
If it improves, then pick up a new drain that a push/push stopper designed for lavs without the overflow.
Also, many times toothpaste will clog the vertical drain below. I sometimes take out the p-trap and the stopper rod and push some paper through to clean that out and then put everything back together again.

The accordion plumbing is going to give you problems too. I can see some cleaning there from time to time.

 

[hj]

remove the "air vent" and test the drainage.

 

[Plumber69]

no you didnt. post a vid of what it does

 

[Reach4]

no you didnt. post a vid of what it does

I watched it. I see the link still on post#1

 

[Cacher_Chick]

Have you had the stopper and control rod out? That is usually where the hairball is.

 

[Themp]

I usually remove the control rod and stopper and then use this to clean down to the ptrap.

https://www.duncraft.com/Feeder-Brush

If that does not work then I remove the ptrap and clean it.

 

[Darrin]

Have you had the stopper and control rod out? That is usually where the hairball is.

I thought I had, but you were right. i pulled it up and out and there was a partial clog ball there. Once removed, it's fine.