# Back to Back Toilets: Double Fixture vs Double Wye

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#### SoConfused

##### Member
Ok, thanks Wayne. Hopefully I'll have time to get this wrapped up this weekend. Can't tell you how much I appreciate the help!

#### wwhitney

No problem, it's been an interesting geometric exercise. I wanted to make (6) simpler, but I don't think it's possible.

Show us some pictures of the final result, even if you end up doing (4.5). And let us know if you want to fix some of the problems visible in your pictures of upstream on the 2" drain. By now you'll be quite proficient so it shouldn't be too hard to do (may require a few more pictures for planning guidance).

Cheers, Wayne

#### SoConfused

##### Member
No problem, it's been an interesting geometric exercise. I wanted to make (6) simpler, but I don't think it's possible.

Show us some pictures of the final result, even if you end up doing (4.5). And let us know if you want to fix some of the problems visible in your pictures of upstream on the 2" drain. By now you'll be quite proficient so it shouldn't be too hard to do (may require a few more pictures for planning guidance).

Cheers, Wayne
Will do! I'll be a little nervous in case I do something you disapprove of but I'll send them!

#### Jeff H Young

So confused As wayne mentioned the 1/4 bend replacement wouldnt quite make code I only threw that out as a workable solution I doubt it will cause problem and prefer a legal long sweep but in any case its 100 times better than what you have with the heel outlet. I hadent read his other solutions very well but Im sure he got something good . trying to save you work and have a good working system.

#### SoConfused

##### Member
So confused As wayne mentioned the 1/4 bend replacement wouldnt quite make code I only threw that out as a workable solution I doubt it will cause problem and prefer a legal long sweep but in any case its 100 times better than what you have with the heel outlet. I hadent read his other solutions very well but Im sure he got something good . trying to save you work and have a good working system.
Thank you Jeff. I appreciate you checking in and giving your input. I'm glad to have a number of options to choose from!

#### SoConfused

##### Member
5) Assuming you don't want to do that, then once the 2" line is jogged out of the way, the simplest option to me is to replace the low heel 90 with a 3" san-tee on its back (where the top will now be just a dry vent) (or use a combo if there's room, but there may not be), then lower the 3x4 reducing closet bend to be at the same elevation as that san-tee (allowing for 2% slope), point its outlet to be at a 45 degree angle to the lower horizontal now 3" only drain, and connect it into the vent take-off san-tee on its back with a 45.
Two quick questions:
1 - In option 5 above, since the upstream WC joins the 3" drain with a 45 to the end of the vent take-off san-tee, I would not have a cleanout, correct?
2 - If I instead end the line with a combo using the open end for a cleanout do I need to add a 22.5 or 45 to the end of it before I put the CO adapter or is it fine for the opening of the CO to be horizontal?

#### wwhitney

I was apparently too wordy : -) Let me draw your attention to the passing comment at the end of post 80, where I said "Also, in 5, where I mentioned a 45, that could be a wye with the straight inlet as cleanout, again if you provide enough access space in front of the cleanout."

Cheers, Wayne

#### SoConfused

##### Member
I was apparently too wordy : -) Let me draw your attention to the passing comment at the end of post 80, where I said "Also, in 5, where I mentioned a 45, that could be a wye with the straight inlet as cleanout, again if you provide enough access space in front of the cleanout."

Cheers, Wayne
Yes! I missed that this morning when I was going back over everything to make sure I had all of the fittings. You're not too wordy - I'm just like a middle schooler trying to read a college dissertation. LOL!

#### Reach4

##### Well-Known Member
Can you run the 2 inch next to the wall, or is there not enough room?

#### SoConfused

##### Member
Can you run the 2 inch next to the wall, or is there not enough room?
I think I could probably run it on either side. That would just give me less room if I needed to do anything to that wall at some point. There's also small ditch along there that runs to the sump pump well. That being said, if it made a big difference in the overall process, it could certainly be done.

#### Reach4

##### Well-Known Member
I think I could probably run it on either side. That would just give me less room if I needed to do anything to that wall at some point. There's also small ditch along there that runs to the sump pump well. That being said, if it made a big difference in the overall process, it could certainly be done.
You have that other drain joining downstream of the toilets. So I was wondering if coming in next to the wall would make things easier. You could possibly insert the wye downstream of that.

I have not been following the current plan... if it works coming in away from the wall, great.

I just looked back. Post #18 has a trap with no vent. Will you deal with that?

#### wwhitney

I just looked back. Post #18 has a trap with no vent. Will you deal with that?
That's surely Phase II, the OP needs to finish the original project first. : - )

But the easiest way to deal with it, if it's the shower as I understand, is to confirm the lav is properly vented, and reroute the lav to join the shower fixture drain upstream of the wye.

Of course, I haven't studied the KY plumbing code, maybe it allows a kitchen sink and washing machine to horizontally wet vent a shower (the current configuration), even though the IPC and UPC don't.

Cheers, Wayne

#### SoConfused

##### Member
You have that other drain joining downstream of the toilets. So I was wondering if coming in next to the wall would make things easier. You could possibly insert the wye downstream of that.

I have not been following the current plan... if it works coming in away from the wall, great.

I just looked back. Post #18 has a trap with no vent. Will you deal with that?
I don't think the other drain downstream will cause a problem coming in away from the wall. As for the trap with no vent, Wayne is right that after I get the toilets taken care of and the 2 inch pipe routed around, I'll look at what's up stream from there. It's been that way since I bought the house in 2003 so I guess a few more weeks won't hurt. Everything upstream of the toilets had already been switched from cast iron to PVC before 2003.

#### Jeff H Young

upon further looks like if you remove that double fixture fitting and use a single street santee it might just work with a long sweep on the bottom could be your drain has extra fall you might can drop it a 1/2 inch.

#### SoConfused

##### Member
upon further looks like if you remove that double fixture fitting and use a single street santee it might just work with a long sweep on the bottom could be your drain has extra fall you might can drop it a 1/2 inch.
The drain goes through a hole through my foundation block so I can't get any more fall. Even with a street san-tee I don't think I have the room to fit a long sweep on the bottom.

When I splice the wye into my 3 inch drain to connect the two inch pipe I won't be able to swing the 3 inch line much at all. Do you guys recommend PVC slip couplings for this or a shielded rubber coupling? I used PVC slip couplings when I spliced the combo into the drain when I did the first WC but even with a friend's help it was a race to beat the glue setting up on us.

#### wwhitney

PVC slip couplings are very hard to use, Fernco 3005-33 or Mission P-300 is the way to the go for 3" PVC to 3" PVC. You'll need 2 if both ends are fixed.

Cheers, Wayne

#### SoConfused

##### Member
PVC slip couplings are very hard to use, Fernco 3005-33 or Mission P-300 is the way to the go for 3" PVC to 3" PVC. You'll need 2 if both ends are fixed.

Cheers, Wayne
Thank you Wayne! That's actually a huge relief to hear. I was afraid it would be considered a hack. Thanks for the part numbers!

#### wwhitney

I'm impressed you got a PVC slip coupling installed with the correct overlap and no leaking, not something I would want to try.

If you want to test all your new work, when you cut in the 3x2 wye, assuming you have sufficient space on the horizontal 3" line, you can also put in a downstream 3" test tee with the opening vertical. Then you can water test everything upstream by screwing in a Cherne Clean-Seal 3" test ball, inflate it, and run water into the DWV until you see it at the first place it would back up, e.g. the shower.

That's the kind of test that's required in new construction [in that case, the fixtures aren't installed, their connections are plugged, and the water is run up one story into the vents, to provide 10' of head pressure] or perhaps for a complete replumb. Not as common to do on small jobs, although your work is getting pretty extensive. Just thought I'd put it out there in case it is of interest to you, I'm not suggesting you should or shouldn't. You'd need to be sure the horizontal runs are well supported for the weight of the water.

Cheers, Wayne

#### SoConfused

##### Member
Well it took me and my friend Jeanna 12 hours in the crawl space but we're finished and everything seems to be working fine. We routed the 2 inch line to the side and tied it in downstream of the toilets, and got rid of the double san-tee and low heel outlet. We tried dry fitting a reducing elbow with a 45 to a wye to allow for a clean out as you suggested in option 5 but couldn't get it to work without what we felt like were changes of direction in a very short space so we felt better about going with the straight 4x3 reducer like we did on the downstream WC. I really don't think it will be a problem since it's within 8 inches of the WC so should have good water pressure at that point. If it becomes a problem I'll pull the WCs and change to 3 inch flanges. I'm attaching pics and hope you guys approve other than the 4x3 reducers!

Teresa

#### wwhitney

Looks beautiful! Sounds like you have a dedicated friend.

Two small notes:

1) The rubber coupling on the vent between the joists should be the same type as you used downstream on the horizontal section. Could be a bit tricky to change, you likely would need to use two of them and cut out an ~3" section. [The piece you put back should be 1/4" to 3/8" shorter than the gap between pipe ends, to allow for the thickness of the stops in the two couplings.] And of course the upper vent section would need to be well supported so it doesn't drop at all while working on it.

2) You could use a couple more straps (every other joist is good), particularly at that horizontal section between the two shielded rubber couplings. It has no strap directly on it and looks like the upstream end is a little low, relative to keeping the 3" all in a straight line.

Cheers, Wayne

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