• We’re currently investigating an issue related to the forum theme and styling that is impacting page layout and visual formatting. The problem has been identified, and we are actively working on a resolution. There is no impact to user data or functionality, this is strictly a front-end display issue. We’ll post an update once the fix has been deployed. Thanks for your patience while we get this sorted.

Plumbing question

S

Sukhoi

Elite Member
I need to modify the plumbing on the drain of a sink. Working backwards, the PVC pipe comes out of the wall. It has a socket-weld to threaded (NPT I hope!) adapter. The PVC P-trap screws onto this adapter, and then into the bottom of the sink.

Are the threads on that adapter NPT? Are there any other threads commonly used in that situation?
 
National Pipe Taper thread. It's the standard thread for threaded pipe fittings. I'm just not sure if that PVC thread is likely NPT or not.
 
Bathroom sinks generally use inch and a quarter, kitchen sinks use inch and a half, almost all I've seen are NPT.
 
Thanks guys! Now I can order all my junk this weekend. I've measured the thread with both a ruler and calipers and both came out to 1 3/4" diameter, so it's a 1 1/2" pipe. It's just amazing how much large threaded wyes are. :Q $26.87 for galvanized iron. I know that isn't great stuff for a drain, but brass is $63.88!
 
Originally posted by: Sukhoi
Thanks guys! Now I can order all my junk this weekend. I've measured the thread with both a ruler and calipers and both came out to 1 3/4" diameter, so it's a 1 1/2" pipe. It's just amazing how much large threaded wyes are. :Q $26.87 for galvanized iron. I know that isn't great stuff for a drain, but brass is $63.88!
Click to expand...

Yep, it can get pretty expensive, but it'll last for years and years without a problem. Also looks a heck of a lot nicer than PVC, even though it's under a sink.
 
See the problem is that McMaster doesn't sell threaded PVC wyes. I have to order from McMaster too. I can either use a galvanized wye or a threaded PVC tee. I'm worried if I use a tee that if the water comes into the tee from the perpendicular direction too quickly it is going to backup into the sink. A wye would eliminate a lot of the backup possibility since the downstream pipe would actually have to get completely full for it to backup.

Additionally I don't really have room to use an unthreaded PVC wye and then use threaded adapters on all sides of it. The inserted piece needs to be as short as possible. Luckily the sink is not used much at all so I really don't think galvanized is going to corrode too quickly.
 
Why are you limited to McMaster??

I find those prices to be amazingly high.
 
Originally posted by: DrPizza
Why are you limited to McMaster??

I find those prices to be amazingly high.
Click to expand...

Luckily it's not my money. It's for a school research lab so all purchasing has to go through the department office for that, and it's a PITA to have to do multiple orders for stuff. We're on time constraints here too. I also need a billion different things from elbows, pipe sections, ball valves, check valves, hose with threaded swiveling connectors of various lengths, and a pump. Much easier to just order it all from McMaster. 🙂
 
You must log in or register to reply here.

TRENDING THREADS

Back
Top