Wye Fittings

**Joe Arcaro** · 02-16-2011, 01:05 PM

Hi:

The attached photo shows wye fittings installed horizontallly on a main waste pipe. Are horizontal wyes ok? The vertical pipes come from the kitchen and bathroom sinks. The main drain exits to the right to a septic tank.
Also curious about the oversized main drain (4"). Anything wrong with that?

Thanks,
Joe

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**CHARLIE VAN FLEET** · 02-16-2011, 01:34 PM

waste drain should have a 1/4 " slope downward to keep solids and liquid from lying on bottom of pipe--see photo

cvf

James Duffin · 02-16-2011, 02:45 PM

Here is what the NC Plumbing Code says about a change of direction.

**Jerry Peck** · 02-16-2011, 06:21 PM

The IRC allows wye for changes in direction from: horizontal to vertical, vertical to horizontal, and horizontal to horizontal.

That looks like it might be being used as a cleanout?

**Joe Arcaro** · 02-17-2011, 06:43 AM

Originally Posted by Jerry Peck

The IRC allows wye for changes in direction from: horizontal to vertical, vertical to horizontal, and horizontal to horizontal.

That looks like it might be being used as a cleanout?

Hi Jerry:

Actually I'm talking the fittings to the left and right of the wye cleanout. What are these fittings called?

**Joe Arcaro** · 02-17-2011, 06:49 AM

Originally Posted by James Duffin

Here is what the NC Plumbing Code says about a change of direction.

Hi James:

So according to the chart, this configuration is ok. Correct?

James Duffin · 02-17-2011, 07:13 AM

Not really I don't think. You have two sanitary T's going from vertical to horizontal and that is not approved in NC. You might want to use a combination y and eighth bend.

**Jerry Peck** · 02-17-2011, 06:33 PM

Originally Posted by Joe Arcaro

Hi Jerry:

Actually I'm talking the fittings to the left and right of the wye cleanout. What are these fittings called?

Joe,

Those are sanitary tees, and sanitary tees are approved for changes in direction from horizontal to vertical only.

Your photos shows those sanitary tees installed changing direction from vertical to horizontal - not allowed.

As James said, a combination wye and eight bend could be used there.

**Ian Page** · 02-18-2011, 02:52 AM

Doesn't make much sense to me to put a Wye for a clean-out there in the first place. Why not install a clean-out and plug the to the left of the kitchen waste? Or, if that's not the beginning of the run, put a Wye for clean-out there before the two vertical waste lines.

ip

**Dana Bostick** · 02-18-2011, 11:37 AM

Wye's are fine IF installed with the branch coming in above the flow line.
The flow line is considered the bottom 1/3 of the pipe. So H to H is okay if you "roll" the fitting and add a street 1/16 bend to get back level on the branch.
No "flat" plumbing allowed.

**Jerry Peck** · 02-18-2011, 06:18 PM

Originally Posted by Ian Page

Doesn't make much sense to me to put a Wye for a clean-out there in the first place. Why not install a clean-out and plug the to the left of the kitchen waste? Or, if that's not the beginning of the run, put a Wye for clean-out there before the two vertical waste lines.

I agree, but ... I could not think of another reason for that wye to be there ... can you?

**Dana Bostick** · 02-18-2011, 07:50 PM

Originally Posted by Joe Arcaro

Hi:

The attached photo shows wye fittings installed horizontallly on a main waste pipe. Are horizontal wyes ok? The vertical pipes come from the kitchen and bathroom sinks. The main drain exits to the right to a septic tank.
Also curious about the oversized main drain (4"). Anything wrong with that?

Thanks,
Joe

Now that I look at the pic again, the San-T's are not allowed "on their back" as installed. 45 degree max incline or change to a combination.
Over sized drains are often used in "flat plumbed" combination waste and vent system like those used in markets etc for floor sinks that are not near a wall for venting. The additional air space above the effluent is used for venting.

James Duffin · 02-18-2011, 08:15 PM

Drain lines are sized to be self-scouring. The problem with over-sized drain lines is that the water will drain leaving the solids behind in the pipe. The code also says that the lowest horizontal sewer has to be 4" in residential so this 4" is not over sized....IMO

**Ian Page** · 02-19-2011, 12:39 AM

Jerry
Looking at the set-up, (the 90 bend on the 1/2" copper on the right also looks crimped to me), I'll give a qualified plumber the benefit of the doubt and say it was a home-owner's DIY attempt. Possibly, if the block wall's return was too tight then maybe there was insufficient room for any meaningful clean-out to the left of the wastes but that could/should have been addressed by better design and planning. Appropriate combos would have provided necessary clearance and significantly less likelyhood of a blockage.

ip