Repairing PVC pipes under sink

[Mark Ezrin]

I am repairing the PVC pipes under a sink. I've got everything measured out and ready to be glued.
I have 1 question about a part I need/don't need.

I've fit everything together and feel like the measurements are correct. I still have a slight leak and assume that is because I've not glued it together and fully tightened it.

I was told to get a heavy-duty washer to place at the top ("A") just under the sink. However, I'm not sure that is the right part. Do I need a slip joint washer at the top ("A") or middle ("B")?

Pls see attached photos.

As always, thanks for your help.

 

[Breplum]

1. You need a tee fitting and need to add an AAV (air admittance valve on top of the tee. Then replumb with a tubular p-trap off the tee.
Coming off the basket strainer we use a "tailpiece washer"

only buy a tubular trap set if it has blue or orange/red beveled washers. For those slip joint washers, we don't like the white poly washers (they will work, just not as reliable)

 

[Sponsor]

 

[Reach4]

See https://terrylove.com/forums/index.php?threads/any-disadvantages-to-using-an-aav.102416/ #3 for an AAV example.

 

[Mark Ezrin]

1. You need a tee fitting and need to add an AAV (air admittance valve on top of the tee. Then replumb with a tubular p-trap off the tee.
Coming off the basket strainer we use a "tailpiece washer"

only buy a tubular trap set if it has blue or orange/red beveled washers. For those slip joint washers, we don't like the white poly washers (they will work, just not as reliable)

Thanks for the info. I am slightly confused. I replaced like-for-like parts from the original builder/plumber. With the possible exception fo the slip joint (or the tailpiece washer?)?

In the back of my mind, I vaguely feel like there was a slip joint washer in the old pipes. Is there a suggestion as an alternative if you don't like the white poly? As in something else to use, or don't use it? Where would it go? A or B?

Or, am I totally confusing the slip joint with the tailpiece washer?


What is the tee fitting I'm missing and where does that go?

Thanks for your patience (and the education).