AAV reconfigure inside bathroom vanity

[Jsmallberries]

This AAV/trap piping was inside a bathroom vanity, I've never seen this before in my neighborhood, same tract homes built the same time, this is the only one without behind the wall venting pipes, that exit through the roof.

The new vanity has drawers and the current set up is in the way. The back of the vanity is open except for a few vertical supports.

Can I come straight up inside the wall and add the AAV at the top with the p-trap pipe through the wall, and add a recessed box with a grill for the AAV. The recessed box/grill will be open to the inside of the vanity since there is no solid wall at the back.

Would this be acceptable? If not, any other ideas?

The other question about this: Above the angle stops, there is a 3/4" piece of pipe that goes straight up, about 18", from the 1/2" CPVC, and is capped. I suppose this is to deal with "water hammer"? Or at least how they did it 25 years ago. Had to repair one side and put it back how it was. Correct assumption and does this work to lessen the impact of water hammer?

 

[Reach4]

I would say the picture close enough. I don't know exactly where you measure the upper part of the 4 inch minimum to. And I don't know if that picture is even yours.

Based on your words, I don't think a box would be necessary, but would not hurt. You need to be 4 inches above the trap arm, and the trap arm needs to be a minimum of 2x pipe diameters between the output of the U to the vent.

See example 2, about 2/3 of the way down https://www.iccsafe.org/building-sa...ps-in-the-2021-international-plumbing-code-2/

Your question seems to be if the AAV being open to the cabinet insides, and whether that is deemed to be sufficient access to atmosphere. I would think so. There are a lot of examples, such as https://terrylove.com/forums/index.php?threads/p-trap-install-stubs-out-too-low.68736/

The old 18 inch pipe for water hammer prevention works by being filled with air when you drain the pipes. Unfortunately the air dissolves in the water over time.

 

[Sponsor]

 

[Jsmallberries]

So not really effective for water hammer over time.
Anyway, I meant to put pipe straight up so it's behind the sheetrock, then put the AAV at the top in a recessed box with a grill, so the grill is open to the inside of the cabinet, since there is no back to the cabinet.

 

[Reach4]

So not really effective for water hammer over time.
Anyway, I meant to put pipe straight up so it's behind the sheetrock, then put the AAV at the top in a recessed box with a grill, so the grill is open to the inside of the cabinet, since there is no back to the cabinet.

I see no problem with that. Sounds equivalent to the AAV being in the cabinet.

 

[letusmaster]

I actually ran into a similar situation during a bathroom remodel a couple years ago, had drawers in the new vanity that totally blocked the original trap setup. I ended up running the pipe through the wall and mounted the AAV up high in a recessed box with a vented grill inside the vanity. Passed inspection and hasn’t given me any issues, just make sure the AAV has enough airflow and is easy to get to later. As for that capped pipe above the angle stops, yeah, that’s an old-school air chamber meant to absorb water hammer. They used to be pretty common, but they don’t always work long-term since they can fill with water. If it’s not causing noise, I’d probably leave it, but if you notice banging pipes, I’d swap in a hammer arrestor, cheap fix and they work way better.

 

[Jsmallberries]

Making progress but I am about 4-5 inches low and off to the side. What piping can be used to match up to the drain tail piece.

See photos, in one there is only about 4 inches from the back of the drawer but there is a proprietary connection that came with the Ikea hanging vanity.(trap 1)

On this new one,(free standing on legs, they don't provide any additional hardware (trap2)

One more question, wanted the glue on for the angle stop but they don't even sell them at local stores, went with Shark Bite. If they don't leak at after installation does that mean that I don't have be concerned about it failing?

 

[Reach4]

https://www.homedepot.com/p/The-Plu...me-Plated-Brass-2-Pack-QACS81412C-2/332859978 are glue-on angle stops . https://www.homedepot.com/p/The-Plu...me-Plated-Brass-2-Pack-QSCS82412C-2/332859907 Are straight.

Sharkbite are good.

Are you asking something about trap2, like how to run the drainage from the back? Is that trap 1-1/4 or 1-1/2?

There are lots of pieces. https://www.homedepot.com/p/Oatey-1...ink-Drain-Outlet-Waste-Arm-HDC2690B/316622003 for example, is 1-1/2.

 

[Jsmallberries]

Don't want to use flex pipe.

From the sink drain tail piece, to get down and over to the P-trap. Can I use 2 right angle slip joints?
Or do they make a right angle tail piece from the sink drain then into a right angle slip joint??
Other ideas?

 

[Reach4]

If you search for handicap drain, you can find metal drains with a built-in right angle. They seem to be more expensive, and tend to have a grid at the input rather than some kind of stopper. But you may turn up something.

How much horizontal offset are you needing?

I guess the answer to the first question in #7 is yes. How about the second?

 

[Jsmallberries]

Thanks for the glue-on angle stop links, they don't have them in stores locally however.

Because of the lower drawer depth, the p-trap has to be that far back, so need to get up and over where the sink drain tailpiece will be. It's about 4-5 inches to the side and same in height.
The piping is 1 1/2'.
What about using two right angle slip joints?
Cut drawer to reduce depth?
Can the AAV be left like that behind the drywall but with a vented grill without a recessed box?

 

[Reach4]

Two right angle slip joints sound good. Or 2 45s if you have the vertical space.

Cut drawer to reduce depth?

Why is that needed? Are you saying that the photo is take with the drawer not closed. If you needed space, you should have not had the trap arm at right angles to the wall. You could cut the riser, rotate CCW as viewed from above, and put on a coupling. If you used a shielded coupling, you could adjust the angle, but if you glue, you need to get the angle right. The U of the trap could be on the left instead of the right.... whatever fits.

Can the AAV be left like that behind the drywall but with a vented grill without a recessed box?

Why not have the drywall behind?....

 

[Jsmallberries]

Nothing glued yet, all dry fit........The right angle slip joints will work, and simply box on the AAV, no grill needed, The latest
problem, just realized with the sink in place, may limit access to the AAV, What about this trap/aav combo in this photo?

Can you comment on this set up, this is under my kitchen sink, 25 years never a problem

 

[John Gayewski]

Neither of the two pictures on post #12 are correct. The picture of the floating trap is crown vented. The second picture under the sink the trap isn't vented the tailpiece is vented which is useless.

 

[Jsmallberries]

What does crown vented mean, and why is that a problem? Why is it sold if not useable?

In the kitchen sink photo, that was builder installed at new construction. Would an AAV at the top of the 3" pipe fix that?

This configuration is good though? see photo

 

[Reach4]

What does crown vented mean, and why is that a problem?

See https://www.google.com/search?q="crown+vent"+plumbing

In the kitchen sink photo, that was builder installed at new construction. Would an AAV at the top of the 3" pipe fix that?

This configuration is good though? see photo

Are both trap1.jpg and trap2.jpg actual pictures of your plumbing? Are you asking about the trap1.jpg picture? That picture does not seem to have a 3 inch pipe. If the kitchen sink photo is trap2.jpg, there is already an AAV.

 

[Jsmallberries]

Sorry, I'm mixing things. Trap 1 is mine, trap 2 is a neighbors( the current work item) The sink is in my house and there is no AAV, that is a clean out cap at the top of that 3 inch pipe

 

[Reach4]

Sorry, I'm mixing things. Trap 1 is mine, trap 2 is a neighbors( the current work item) The sink is in my house and there is no AAV, that is a clean out cap at the top of that 3 inch pipe

Trap2 has an Oatey AAV atop the vertical pipe, and the protective wrapping is still in place, which prevents it from functioning as an AAV.

"kit sink.jpg" looks like it might have a 3 inch pipe with a cleanout cap. The stuff in that picture is FUBAR from my point of view.

 

[Jsmallberries]

Thanks R4, Trap 2 just dry fit, not operational for now. Going over to look at it later today.

Had to look up fubar, kinda like snafu.

For the kitchen sink drainage, builder installed passed code inspection back in 2000, but then again, they had to tear out and rebuild master shower 6 months after closing.

 

[Reach4]

kinda like snafu.

but without a hint of the "normal" aspect.