2" or 1.5" under sink?

I know the drain line should be 2" for a kitchen. However every under sink connection I see at the store is 1.5" or smaller. So how close do I have to get with the 2" pipe till I can drop to the 1.5"? This is one lay out idea I hadsee pic)
2" to a 90 with a clean out on the end under the sink. In line is a long sweep 1.5" T off the 2" line for the drain. This look like it would pass inspection?

The other question I have is should I use the larger 1.5" trap as shown or the smaller fittings sold for such applications localy? (shown to the left) This will be a double sink with a disposal.

I would eliminate the C/O and tee 90 out of the wall.Then use 2x1.5tee.
From your stackand use the shc40 trap as you can allways clean it out
at the trap.Our codes are different but it still looks OK to me.BTWtyping one handed

ditto.

You asked several Q's in one question -- so I'll try to separate them into bitesize pieces.

In both size P traps you have bought, there is a slip joint at the trap, and this allows you easy access into the pipe if you need it. Thus, you have enough access already and don't need to complicate your pipe layout with a cleanout and that long quarter bend.

Plumbers may tell you more about that layout; I am not at that level. Perhaps it is a good thing to do... I wouldn't know.

Eliminating the Cleanout means your pipe comes straight out from the stack at the left hand side. That is simpler. Since the P trap is attached with a slip joint you don't need any significantly better access. You can also use two 1/8thbends (135-degree elbows) to create a zigzag pipe shape, if you want to make the pipe follow a different course from a straight line. That is an Offset. You can buy whole pipes made as offsets too. I think they move the pipe six inches over. It will put the pipe closer to the wall.


The small size shown is probably 1.25" in diameter on the inside; it can only be used for a single hand rinse sink next to a toilet.

Anything else takes a 1.5" diameter pipe.


So, from the stack you need to reduce the 2" using a 2"-to-1.5" reducer, or buy a 2-2-1.5 Sanitary Tee instead of the 2-2-2 you have bought.



David

geniescience said:

The small size shown is probably 1.25" in diameter on the inside; it can only be used for a single hand rinse sink next to a toilet.
David

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The funny thing is that small trap came with a hook up kit sold for double sinks with a disposal and dish washer. I think it will have to go back in favor of buying individual parts of the proper size.

If I use the PVC trap and connect it directly to the drain pipe coming out of the wall then the first available opening will be the down turned 90 at the start of the trap. Is tat OK for a clean out? Sounds like a PITA to me. I am also tempted to build the entire under sink assembly out of PVC and just put some unions in in strategic locations. That sound like a good idea or should I stick with the thinner plastic parts? I have never had one give me problems. One thing to note is there will be a clean out directly under the floor at the back of a long sweep T where the drain turns horizontal.

tjbaudio said:

The funny thing is that small trap came with a hook up kit sold for double sinks with a disposal and dish washer. ...

Click to expand...

It may be 1.5" after all. Measure it first.


The parts that connect two sinks to a single P trap are called "Continuous Waste" -- either "End Outlet" or "Center Outlet". These parts ahve no bearing on what comes after the P trap.

David

tjbaudio said:

.... then the first available opening will be the down turned 90 at the start of the trap. Is tat OK for a clean out? ....

Click to expand...

not true. You can have a clean out anywhere along the pipe between the Ptrap and the SanTee that is on the left hand side of your picture. You just need to imagine it being there. Then, you cut the pipe and insert it.

David

p.s. there probably is a lot that I haven't understood in your post ... you say you are "tempted to build the entire under sink assembly out of PVC ... thinner plastic parts...." and I have no idea what distinction you are making between "types" of plastic or whatever it is you are referring to.

Someone else may have more insight.

The thinner plastic I am refering to is the 1/8" thick stuff you may see under a sink. I think it may be ABS. This is in comparison to the 1/4" or so celualr core PVC normaly used around here for DWV.

For that clean out, can it be a saniT on its side?

Kitchen Sink Plumbing


HI go with the clean out where you have it, ask yourself what would happen
with a clogged sink where do you want to dirty water out of and be able to run snake into ???
i like the heavy sch 40 pvc p-trap!! because i can run a power snake down though it, But if you pull that trap to run a sewer cable though the 90' ell
many times it will wear a grove with the snake, and prevent the the p-trap
from sealing when you go to put it back togeather!!
the thin wall trap can be pulled apart and allow you to run snake,
you want to put the disposer where it can flow stright though the p trap
and let the other side be offset off your deverter tee,


MACPLUMB MASTERPLUMBER & MASTER DRAINMAN

tjbaudio said:

.... For that clean out, can it be a saniT on its side?

Click to expand...

use a Wye or the Combo (on its "back") like the one you already have laying flat on its side in the middle of the picture. Assuming here you were referring to the CleanOut you want to install in the middle of the pipe that goes from the stack to the P trap. Not in or at the P trap.

i now see you were calling one thickness ABS and the other thickness PVC. That may be the types of plastic in those two, or they may be all the same (either PVC or ABS). It makes no big difference; they just take different glues but they are basically the same in most characteristics; not a concern.

david

A thought I had today was to change where the pipe in the floor is. Since nothing is ran yet it is not a problem. So here is a pic of my new ide. I figuer by making this change I eliminate one horisontal run right under the sink.
I was toying with the idea of not having the cleanout under the trap becasue there will be a clean out just under the floor but it seams like a good idea to be able to l look in there. However I could eliminate it and put the PVC trap in with a pair of threaded couplings. If I do this, what do I use on the threads to keep it sealed? All my other clean outs have petrolium jelly on them. Could I do the same here?
The other problem I see with this is the horisontal vent. I will get it up to 44" or so(this is in a 1/2 wall)

Thanks guys.

lower trap arm, put clean out higher.

-david

geniescience said:

lower trap arm, put clean out higher.

-david

Click to expand...

I hope that's a joke.

the vent needs to be above the fixtures flood rim before it goes horizontal (in my area).

BAPlumber said:

I hope that's a joke.

the vent needs to be above the fixtures flood rim before it goes horizontal (in my area).

Click to expand...

I thought about puttign the clean out higher but then I would need to take out every thing to get at it any way. So I am going to leave it low. I am also going to make the trap arm removable. plus moving the vent higher, I can get the vent up to 42" on center with a 36" counter hight.