Hi,

First, how do you connect 2" UPVC wall DWV to either 1-1/2" or 1-/14" p-trap?

What most do, which I don't think is the correct way is to fill the voids with vulca seal or silicon, while some use reducers, but still fill the gaps either with silicon or vulca seal.

What I'm after is to stick a trap adapter in that 2" DWV and just place the trap and tighten the nut. Something like this below:

Personally, I'd go for a spigot joint and a reduer for the 2" DWV. I need both 1-1/4" and 1-1/2".

http://www.nibco.com/Fittings/Plastic-Fittings/PVC-DWV-Fittings/4804-2-Male-Adapter-Spg-x-MIPT-PVC-DWV/
http://www.nibco.com/Fittings/Plastic-Fittings/PVC-DWV-Fittings/4801-2-F-Flush-Bushing-Spg-x-H-PVC-DWV/
http://www.plumbingsupply.com/escutch.html#dbox (to hide the adapter)

Now, I can't seem to find the 3 items I posted above anywhere, unless they slipped my eye... been to home depots and the the sales said they never had any of those yet 🙁

Thanks,