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This seemed so much easier in my head before I started.

The sink drain is just about directly over the waste pipe. I glued this together with two 45s and a 2 to 1 1/2 wye. I need to connect an AAV to the top of the wye. The P trap doesn’t line up perfectly with the top 45. I’m not happy with it, it’s forced. The P trap does not screw together easily. I have access to the basement it’s open. I was thinking about cutting off the bottom 45 and starting over. Any suggestions on how I can do this the right way?

enter image description here

Rohit Gupta
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Paulz
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  • IIRC you may need a sanitary tee instead of a normal wye to slow down flow rate to prevent siphoning out all liquid from the trap. You may also need a vertical to raise the AAV higher. Other than that, did you dry fit it all first? – Armand Apr 09 '23 at 06:43
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    That is a sanitary tee, there isn't a wye in this picture. – Ecnerwal Apr 09 '23 at 13:06
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    You are correct it is a sanitary tee, I’m sorry. – Paulz Apr 09 '23 at 14:47

3 Answers3

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Since this is NOT buried in concrete, don't use a glue-together trap at all.

Problem the first (apart from what you mention) is that the vent is too close to the trap - it needs to be at least 2 pipe diameters away from the trap or it's a "crown vent" and (even more) prone to clogging. One plunger event later and your AAV is full of sink clog crud. Problem the second is that 45 degree pipes are OK in vents, bad in drains - drains should either be vertical or "horizontal" (at proper slope, 1/4" per foot in this size) because excessive slope tends to have the liquid run away leaving solids behind, and those solids build up in the pipe until it clogs.

Buy a polypropylene slip-fit trap (which has the same exit the sink tailpiece does, and the entrance compression fitting for the sink tailpiece built in.)

Crude drawing.

The elbow in the lower left should be a "long-radius bend" not a sharp elbow - takes too much time to draw nicely

Put a cleanout in the elbow (so, use a sanitary tee with a cleanout plug, not an elbow) where the drain comes through the floor, and then (maintaining proper 1/4" per foot slope) go sideways far enough that when you come up, the AAV can be well away from the trap exit (minimum 2 pipe diameters) and make sure to extend upwards from that tee so the AAV is also as high as possible (but still able to be unscrewed and replaced) in the cabinet, if you don't run it even further up inside the wall cavity to an access panel (so it can be replaced when needed, but "when needed" may be less often.)

Alternatively, move the pipe in the basement and drill a new hole that's not poorly placed right under the sink

From there, extend the pipe back towards the trap (maintaining proper 1/4" per foot slope) and install the trap adapter on the end of the pipe. The combination of the slip-fit on the tailpiece and the slip fit entering the drain (plus the union joint in the middle of the trap) provides considerable adjustability to get things right, as opposed to a "glue and pray and then swear" approach that a glue-in trap requires. Note that slip fit ends (on the tailpiece and trap exit) can be trimmed to fit if they are too long, but you should not overdo that (they have a couple of inches of adjustable range.)

Ecnerwal
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    I like this approach the best, I will give this a shot today. Will dry fit everything prior this time. Will update later. – Paulz Apr 09 '23 at 14:48
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    Be aware when dry-fitting PVC (or ABS) that the pipe will (or at least should) go *a little bit further* into the joint when you solvent-weld ("glue") it together. The sockets are slightly tapered, and the cement softens the pipe material so it goes into the taper further before bottoming. – Ecnerwal Apr 09 '23 at 14:56
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    It's unintuitive that intermediate slopes are worse than minimum slope. Thanks for that pointer. – jay613 Apr 09 '23 at 16:38
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enter image description here

Ended up moving the waste pipe in the basement for a cleaner look. Let me know what you guys think.

Paulz
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    Just in case you aren't aware- others won't get a notification about this answer. If you're looking for specific feedback (and from "let me know what you guys think", you seem to be), you might want to comment or the others answers and/or stop by [chat](https://chat.stackexchange.com/?tab=site&host=diy.stackexchange.com). You _might_ be just shy of sufficient reputation to chat, but I think I moderator should be able to invite you to chat if so. Cheers! – bertieb Apr 09 '23 at 19:38
  • Its tidier. A bit late but the horizontal piece needed to be an inch or so longer, to avoid the strain on the joint at the sink. – Rohit Gupta Apr 09 '23 at 20:28
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    I think if you did all this work you should have taken the advice in @Ecnerwal's answer about adding one more slip joint. There seem to be some strange angles and stresses there that can contribute to leaks later. If you feel like fixing it, I'd also point the horizontal arm more towards the back and make it longer, with a slip joint, so that the trap is pointing more backwards, which maximizes storage space. Hopefully you didn't also ignore the advice about adding a cleanout, since you have no useful point of access here without the suggested horizontal trap adapter. – jay613 Apr 09 '23 at 21:00
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    Is that drain sloped upwards? – JMac Apr 10 '23 at 13:23
  • Agree with Rohit Gupta - the near horizontal pipe is too short, causing strain on the trap itself. – Tim Apr 10 '23 at 13:33
  • From here, just buy the right trap and a trap adapter, cut off the wrong trap, glue on the trap adapter, install the right trap, and the strain should be off. The damage to your wallet from buying a second trap that requires a degree of pipe-glueing precision that's hard to manage in practice has been done already, unfortunately. – Ecnerwal Apr 10 '23 at 15:57
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Here is a suggestion

drain

You would need 3 x 90° outlet elbow with captured nuts

I would not glue but use Threaded for IPS

Ruskes
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