Vanity drains funny - why?

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geoffhazel

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New vanity installed in powder room. New sink is a glass bowl with no overflow. The new vanity has two pull out "trays" that interfere with the P-trap, so I put in some little elbows to get to the existing drain, leaving the P-trap above the pull out trays.

Now, at first I used one of those accordion style pipes and bent it into an S and that worked but exhibited the odd behavior:

A little water in the sink just sits there. Once it gets full enough, it all drains in a big rush. Then it starts filling up again.

If you run just a bit of water, like you're rinsing off your hands, the water sits in there forever, not draining at all.

So I took out the accordion pipe and put in two L's like you see in the picture. It's better than it was, but still has the "small amount of water not going down" problem.

I took a video of it filling and draining. If you run the water, it fills up a ways, then drains all at once, fills up, drains, etc. See it here: http://youtu.be/3wFtld1PNt8?list=UUymEW4hkZ0un-Nsrla-Ynqg

I figure it has something to do with the venting. The homeowner says it never had this problem before.

If I took out the trays and lowered the P-trap so that it was a straight shot into the wall drain, do you think that would fix it?

Oh, and early on I thought "I wonder if someone jammed something into the pipe to keep the sewer gas from escaping?" because the sink had been missing for a month or so. I fished around in the pipe and found nothing. Furthermore, the owner said she had been "smelling something" so that confirmed that there was nothing blocking the pipe. Also, if you block the drain and fill the sink, it all rushes out with vigor; if there was a block in the pipe, I'd expect it to stop while it was rushing -- but it won't do that. Once it starts rushing, it finishes emptying. The problem is getting it started with a limited amount of water

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I figure it has something to do with the venting. The homeowner says it never had this problem before.

To answer the question in your post title: "why?" because you totally screwed it up. You have no idea of how to plumb. From your post you tell us you are doing this for someone else. In every area of the country what you are doing is illegal. You are a really bad HACK.

The drainage problems you have are all caused by your installation. Easy fixes for a trained professional who has been trained and LICENSED to work on other "homeowners" plumbing. The facts of how you plumbed the drain both originally and now glaringly illustrate why HACKS are not allowed to work on plumbing. The homeowner should throw you out of their house immediately and call a qualified plumber to replace the mess you call plumbing. Oh, and by the way, the homeowner does not legally have to pay you for your unlicensed work.
 
What a mess. Take all that out and start again. If it means you have to cut the vanity to make room for the the p-trap, then that's what you have to do. You cannot plumb it like that.

That's the stuff we have to deal with when customers buy junk because it's pretty looking. Nobody with a brain ever looks ahead to see if it's proper for their application.
 
Hey, look: I was trying to plumb it so I didn't have to mess with the vanity trays, OK? I know how to do it "normally".

I'll pull the trays out and put in the p-trap so it goes straight into the wall, fine.

Would any of you "professionals" care to share the physics of why it behaves the way it does right now?

(I thought this was a friendly place for plumbing advice -- didn't expect all the hate)
 
This is a friendly place to ask plumbing questions. I honestly don't know why the sly comments, other than the silly narration on your video? ;) I do believe that based upon your post, it appears that you installed this yourself as a professional plumber and not a home owner. If you are a professional, I too would question why this was posted in primarily a DIY plumbing help forum?

I believe if you eliminate the s trap and install the straight pipe, your problems may just go down the drain.

BTW, I loved watching the YouTube video of the live fire exercise on the naval ship.
 
This is a friendly place to ask plumbing questions. I honestly don't know why the sly comments, other than the silly narration on your video? ;) I do believe that based upon your post, it appears that you installed this yourself as a professional plumber and not a home owner. If you are a professional, I too would question why this was posted in primarily a DIY plumbing help forum?

I believe if you eliminate the s trap and install the straight pipe, your problems may just go down the drain.

BTW, I loved watching the YouTube video of the live fire exercise on the naval ship.

I agree. Everyone must be having a bad day.
 
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So what I'm puzzling over is why a small amount of water won't drain. With a normal sink with a stopper, there's nothing impeding the water from going down the sides of the pipe. This sink, however, has that drain cover with the little holes.

aside from the S bend, could that drain cover with all the little holes be causing a problem?

And would that problem be aggravated by the S bend? And switching out to a normal P-trap with a straight shot to the main-line would solve that somehow?
 
This is a friendly place to ask plumbing questions. I do believe that based upon your post, it appears that you installed this yourself as a professional plumber and not a home owner. If you are a professional, I too would question why this was posted in primarily a DIY plumbing help forum?

Yes havasu. I love offering advice to DIYers but get my blood pressure up when someone who is working as a "plumber" for someone else, does such an incredibly bad job and then has the audacity to ask for advice from real professionals on a DIY forum. I bet all the while the OP has not once told the customer he does not have any idea how to plumb the sink drain.

The answers to all of the questions in the OPs first post and last post are basic plumbing knowledge. If the OP were a DIYer I would have been happy to offer advice. But I will not help this hack out of his dilemma of his own creation,
 
Gotta admit though....it is kinda funny.

Not for the homeowner though. I hope at least the labor was free.
 
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This sink, however, has that drain cover with the little holes.
here is why it drains funny
Most sinks have an over flow. That over flow allows air into the drain like a vent. the grid strainer in your sink has a flat surface and makes if more difficult for the water to flow through it. the air in the tail piece has to escape to allow the water in. occasionally the vortex of the water draining opens an air hole allowing the water to quick suck down sucks.

Do an experiment.
cover the drain with a piece of paper or ?. Fill the sink and turn off the water flow. The water running into the sink interrupts the natural occurrence of the Coriolis effect. Remove the paper and watch how it drains out of the grid holes. SLOW

The grid kind of inhibits the Coriolis effect.
Use your finger and spin the water a little.
Clockwise if you're in the northern hemisphere.
once it develops a air hole in the center you will notice it will drain must faster.

Several things are contributing to you drain phenomena.
Grid strainer
no overflow
The trap are not vented properly. which can cause the water in the p-trap to siphon out and also result in sucking out the bowl as seen in the video.

The little experiment I have done. Had a customer that had someone install 2 sinks side by side in a similar manner. I cleaned the drain for the buildings Home Owners Association. Wasn't there to fix his junk.

He complained to the HOA that the drains were still slow so I had to go back and prove to him that it was because of the way they were piped. Not My problem.

Stupid cabinets with drawers in the bottom.

Those sinks look pretty cool but cool is not always practical :cool:
 
Mr. David, what is the hypothesis on the Coriolis effect for the rounds ricocheting of the water?



:D
 
Not the under plumbing at all. The little holes in the drain had sufficient surface tension to block the drain. This new drain works great with no other changes.

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I figured it out. your irritating voice . the cousin/whiner/looser on the Jerry Seinfield show. thats who you sound like.

you might have gotten the water to drain a liitle better. but it is far from fine

here is a little experiment for you. put a straw in a glass of water, put your finger over the end of the straw, pick straw up out of liquid
it does not drain, take your finger off the end of straw, it will woosh out

the F*&%ED up plumbing under that sink. when it fills with water. the finger is on the end of the straw.

it will continue to be F*&^$ed up, till you get rid of that "S" trap

the home owner will have nothing but grief, hair clogs, and soap clogs due to your plumbing ignorance

WHAT REALLY CHAPS MY ASS....is you came back on this forum. CROWING like an idiot. that you fixed the problem by changing out the strainer

instead of taking the advice of professionals and doing away with the "S" trap.
 
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