I'm considering misusing a Sanitary Tee!!!

Old 05-09-05, 11:15 AM
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I'm considering misusing a Sanitary Tee!!!

In a previous remodel a bathroom was installed in a room built up on 2x8s over a former garage. As a consequence of limited vertical space a fairly tight 3" 90-degree bend was installed under the toilet and --to make things worse--the 3" drain leading off from that bend lacks sufficient slope.

To hopefully improve this situation, I am running the drain line off in a different direction--giving it the needed 1/4" in 12" slope. Actually this new route eliminates about 20' of pipe and 4 90-degree bends. But I am still stuck with that limited clearance under the toilet.

What I want to put in is a 3" x 3" x 2" Sanitary Tee--ON ITS BACK! The 3" legs of the Tee will make the bend from the toilet into the waste line, while I will bring the 2" drain from the sink and shower into that Tee through the straight (horizontal) 2" opening. Unlike the existing installation, this will at least put other fixtures upstream from the toilet--with water flowing in from the sink to flush the fitting out. Presently the toilet and that 90-degree bend are at the upstream point on the line with toilet waste being the only thing that goes through the 90-degree bend--with no cleanout in reach!

I know that what I propose is a misuse of the San-Tee, but it still seems like the best option. The only other thing I can do is keep the 90-degree bend--into a horizontal wye. But there will be only toilet waste going through the bend. There is insufficient space for a 3" combo (wye+45) on its back under that toilet. The radius of the present 90-degree is essentially the same as the San-Tee, and it has nothing to flush through it. In the new installation there will be cleanouts both upstream and downstream from that San-Tee.

I'm open to comments and advice before I actually do this.

Edited to add: there may be one other option, that is to set a 3" wye on its side, with the toilet flushing into one leg of it through a 90-degree bend, and the lavatory and shower entering the adjacent leg of the wye. This introduces a horizontal 45-degree to the waste flow.

Last edited by Wendell; 05-09-05 at 02:45 PM.
Old 05-09-05, 07:23 PM
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Take pictures of your situation.

If you tie into that toilet immediately after the closet flange.......anything after that has the capability to be siphoned with no vent in front of any other fixture between the toilet and the stack.

Meaning, you flush the toilet and the vanity or the tub is going to lose its trap water because the toilet wasn't vented first.

First thing that will happen with a sanitary tee laid on its back will be that it will clog, the inside was never designed for smooth flow in that fashion.
Old 05-10-05, 08:53 AM
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Upstream of the wye or san-T are two 2-inch vents, one at the shower and one at the lavatory. But, I understand what you are saying about the potential for the San-T to clog. I am hoping that by running the shower and lavatory through the San-T horizontal that it will keep the San-T free.

My primary concern is that, because the San-T isn't designed to direct water through it in a hurry, that the syphoning of the toilet bowl will be impeeded.

Even if I had room for a 3" wye-45 combo, laying it on its back messes up its nice flow, since everything will just drop through into the straight (horizontal) leg of the combo--and not really make the bend nice and smooth.

It seems my best alternative is to run through a 90 bend into a Wye laid flat, with the shower and lavatory entering the drain through the other leg of the wye.

In fact, this toilet is a wall-hung, and I am looking into the availability of a 45 discharge El. That will allow a connection through a Wye.

The advantage of the San-T configuration is that I will be able to snake up the line all the way to the shower from a 2-way cleanout right below the San-T (and outside a wall).

Thanks for your advice.
Old 05-10-05, 04:44 PM
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You stated the advantages of the san-tee but the disadvantages far outweigh them. I will not go into why it is an illegal connection but do remember what Steve (Dunbar) told you.

Hey, my advice...Better buy a decent closet auger (one of those Ridgid K-6's would be great for this application) and pickup a used sewer rodder with about 25 feet of good cable.

Good luck with your project...
Old 05-16-05, 12:45 PM
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I used your advice: didn't use the San-T.

The WC discharge el (it's a wall-hung toilet) drops right into a broad-bend 90, which runs straight to the sptic tank. The shower and lavatory 2-inch drain enters that line just downstream of the WC through a wye. The lavatory and shower vents (each 2") wet-vent the toilet. Job done. This little project eliminted 24 feet of drain run (some of which had no drop!) and 4 flat 90-degreen bends.

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