Green Tractor Talk banner

1 - 18 of 18 Posts

·
Registered
Joined
·
825 Posts
Discussion Starter #1
Anyone wanna take a stab at why there is a closed loop above this S trap? I've never seen anything like it but I'm planning to replace this vanity soon.

IMG_20180513_121107019.jpg

Sent from my Moto G (5) Plus using Tapatalk
 

·
Registered
Joined
·
1,838 Posts
My guess would be that someone thought it would work like a vent without actually venting.

It could also be for a planned expansion. Maybe a double sink? Doesnt make sense to do that, since PVC is pretty easy to work with.
Either way, whoever did it was most likely (hopefully) not a licensed plumber...
 

·
Registered
Joined
·
825 Posts
Discussion Starter #3
My guess would be that someone thought it would work like a vent without actually venting.

It could also be for a planned expansion. Maybe a double sink? Doesnt make sense to do that, since PVC is pretty easy to work with.
Either way, whoever did it was most likely (hopefully) not a licensed plumber...
Agreed, it looks like someone could have easily glued a vent cap on the 1-1/2" tee and called it good if that were the issue. I'll probably just cut the loop out.

Sent from my Moto G (5) Plus using Tapatalk
 

·
Registered
Joined
·
1,067 Posts
The only place we've used them is a kitchen island where there is no possibility of a stack option. Local code doesn't allow a mechanical vent so we use these but never in a vanity. If your plumbing wasn't vented properly, a plumber could have added this to remedy a drain issue.I would elect to keep the loop if that's the case as opposed to a mechanical vent. Check your local plumbing codes. You could run into issues if and when you decide to sell.
 

·
Premium Member
Joined
·
2,112 Posts

·
Registered
Joined
·
1,067 Posts

·
Registered
Joined
·
825 Posts
Discussion Starter #7
Exactly! It's easy in new construction. I'm not a plumber but we've done this in the exact way the video describes in kitchen islands and it meets our local code.
Just thinking outside of the box here, maybe they didn't have a 1-1/2" cap but they did have plenty of sweeps and extra pipe...

Sent from my Moto G (5) Plus using Tapatalk
 

·
Registered
Joined
·
1,067 Posts
Just thinking outside of the box here, maybe they didn't have a 1-1/2" cap but they did have plenty of sweeps and extra pipe...

Sent from my Moto G (5) Plus using Tapatalk
I'd check your stack situation. We've seen some homeowners take some desperate measures correcting something as simple as removing a bird nest.
 

·
Registered
Joined
·
825 Posts
Discussion Starter #9
I'd check your stack situation. We've seen some homeowners take some desperate measures correcting something as simple as removing a bird nest.
I've never had an issue with water draining aside from when my in-laws came over and jammed corn husks and cobbs down the disposal after dinner. Apparently they do not have an issue with that at their home.

Sent from my Moto G (5) Plus using Tapatalk
 

·
Registered
Joined
·
757 Posts
I agree it's likely a venting alternative. I would rather use a ~$22 Air Admittance Valve (AAV). Home Depot, Lowes, and Ace all carry them.

If you want more reliable advice, I've always gotten really great responses from pros in both the plumbing and electrical forums on Houzz. Those folks are fantastic.

https://www.houzz.com/discussions/plumbing
 

·
Registered
Joined
·
3,687 Posts
Hopefully this is not hijacking, but, I have a vessel sink,, and it has a problem that I believe a stack vent or an AAV will not correct,,

:flag_of_truce:

Every sink I have ever seen has a vent tube cast into it, that vents air out of the drain, into the room.
A vessel sink, being hand-made from a block of granite, etc,, does not have that vent.

So, if water goes in the sink a certain way, it will "seal over" the drain, and will not start draining,,,
until enough water is in the sink to "force" the air in the drain to "burp" up through the water.

This does not happen all the time, but, occasionally. Once the air burps, the sink drains normally.

The plumbing tube shown by the OP might be a fix for an un-vented sink?? :dunno:
 

·
Premium Member
Joined
·
2,112 Posts
Exactly! It's easy in new construction. I'm not a plumber but we've done this in the exact way the video describes in kitchen islands and it meets our local code.
Yep. I'm not a plumber either but do no something about plumbing. The loop just doesn't make sense.
 

·
Registered
Joined
·
306 Posts
They’re using it as a venting alternative. Cut out and replace with air admittance valve. Here we don’t use pvc but instead dwv. I imagine without proper venting or use of an AAV you will get “chugging” when sink is draining
 

·
Registered
Joined
·
3,248 Posts
Hopefully this is not hijacking, but, I have a vessel sink,, and it has a problem that I believe a stack vent or an AAV will not correct,,

:flag_of_truce:

Every sink I have ever seen has a vent tube cast into it, that vents air out of the drain, into the room.
A vessel sink, being hand-made from a block of granite, etc,, does not have that vent.

So, if water goes in the sink a certain way, it will "seal over" the drain, and will not start draining,,,
until enough water is in the sink to "force" the air in the drain to "burp" up through the water.

This does not happen all the time, but, occasionally. Once the air burps, the sink drains normally.

The plumbing tube shown by the OP might be a fix for an un-vented sink?? :dunno:
Not sure that it will help. We have a double sink in the bathroom that is the same way. There is no overflow drain so it is like they don't get air and are slow to drain until they get kind of full. It doesn't help that the drain stoppers that we used are kind of restrictive. It kind of bugs me because when I shave it takes a while to get the sink cleaned out since the shaving cream floats.
 

·
Registered
Joined
·
3,687 Posts
Not sure that it will help. We have a double sink in the bathroom that is the same way.

There is no overflow drain so it is like they don't get air and are slow to drain until they get kind of full.

It doesn't help that the drain stoppers that we used are kind of restrictive. It kind of bugs me because when I shave it takes a while to get the sink cleaned out since the shaving cream floats.
So, I think the truth comes out,, what we always thought was an overflow,, was not,,

That vent hole high and inside most sinks is an air outlet that allows trapped air out,,,
 

·
Registered
Joined
·
3,248 Posts
So, I think the truth comes out,, what we always thought was an overflow,, was not,,

That vent hole high and inside most sinks is an air outlet that allows trapped air out,,,
It probably does a bit of double duty. I was always debating on if it is the design of our drain stoppers. They both do it. They are both held in place by friction so I normally just pull it out rather than stand there. Of course once it is pulled, the drain works great even before it starts a vortex and sucks air. I just think it might be a combination of no vent/overflow and a somewhat restrictive design. I just haven't found any other style I like better to replace the stoppers.
 

·
Registered
Joined
·
286 Posts
Maybe a temporary support while installing countertops? A hidden antenna; the previous guy was a CIA spy?
 
1 - 18 of 18 Posts
Top