Help connecting a PVC toilet flange to an existing brass drain

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poppity

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I have a several part question, and I don't think something like this has quite been asked here before. So I'll try to be as detailed as possible!

I'm redoing the 2nd-floor bath in my ~1875 condo. I've cleared everything out, including about three extra inches of layered flooring. My primary concern involves the toilet. I unsweated an old brass flange from a 3" brass drain pipe so I can install a new flange to sit on top of a new tile floor. As you can see in the photos, the flange connected with a three-inch-or-so section of vertical pipe, which drops into a 90-degree brass curve. The short vertical section unsweated itself when I removed the flange, but I've left it for the moment (in case you guys recommend resweating it). The curve connects to a nearly four-foot-long horizontal section of brass that connects to the cast iron stack. Here's where the questions start:

1. After looking at the attached photo, is there a crack in the connection between the horizontal brass drain pipe and the stack? If so, do I need to be concerned? Can it be patched, or do I need to replace the entire connection between my drain and the stack?
2. If the "crack" is a non-issue, can I connect PVC (or ABS?) to the existing brass pipe and then connect a PVC (or ABS) toilet flange?
3. If so, where should I connect the PVC/ABS to the brass? Should I cut into the horizontal brass pipe and connect PVC there using a rubber slip-over coupling with clamps? Or can I use a slip-over coupling to connect the PVC flange directly to the curved brass elbow? (This would be ideal, as there's an existing vent just below where the flange will connect.)
4. Is it possible/necessary, to resweat the short vertical section of brass pipe that came loose without removing any flooring?
5. If this nuttiness will work, do I have to use any kind of cement or adhesive when connecting the two pipes with a rubber slip-on coupling? Everything I've read about connecting brass to PVC suggests a rubber coupling, but doesn't mention anything about any sorts of solvent.
6. Finally, is there any reason I can't use a four-inch-wide flange that tapers to a three-inch connection?

I think that's it, depending on what you guys think. Please let me know if you have any questions, if someone's already answered all these questions, and thank you so much in advance!

:Chris

01overview.jpg02stack_connector.jpg03flange_location.jpg04brass_drain_underneath_floor.jpg05elbow_connection.jpg
 

poppity

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The existing bits

Thanks for that, Smooky. If I have to replace that connection, that might indeed be helpful!

Of course... I'd rather not remove the existing bits leading to the cast iron if I can help it. Anyone have any other thoughts on what I posted in my original posting, about what looks okay and what doesn't?

Thank you!
 

Ontario Plumber

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Providing the connection where the horizontal copper drain enters the stack is okay, I would cut the 3 inch copper drain close to the stack and run the drain with ABS pipe with a new ABS flange screwed to the floor. Use a 3" copper to 3" ABS MJ coupling to connect the old copper drain to the new ABS.

Is the vertical section of drain that connected to the old flange lead? it's difficult to see from the pictures.
 

poppity

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Cracked Stack? Mmmmmmmayyybe?

The section of the drain that connected the flange and the drain is copper -- and it's loose now. Enough heat transferred during the flange removal that it unsweated itself. That's probably moot now, though, because I think your advice is good: to connect new ABS drain and flange into the horizontal copper... if the connection from the copper to the stack is okay. I'm quite concerned about that, actually. I don't know if you can see in the photo -- maybe I should take a new shot -- but the connection sure does look cracked to me. If it is, is there any way to fix it without replacing that section of the stack?

Honestly, I'm leaning towards replacing it, just to be on the safe side. I really don't want to, but it's the safe way to go. In which case, I'll connect all new ABS from the stack to the drain/flange. HOWEVER....

The current drain has a vent right on the curve before the four-foot section of horizontal copper (see my third photo). Is this an old-school method? I haven't seen much in the stuff I've read/watched suggesting anything like this. A vent, yes, but shouldn't the vent be closer to the stack? Is this secondary vent on the curve of the drain, just below the flange necessary, or should I leave that out when I replace that piping? It looks like overkill, but I'd hate to skip something essential.

Thank you! Great advice!
 

Cacher_Chick

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I don't live where you do, but my plumbing code would not allow the flat vent to remain on the closet bend. We cannot see "the big picture" of what you have there or whether any of it would pass by today's standards.

If you are doing this work with a permit/inspection (which you should be), you might need to correct the existing violations and demonstrate a pressure/stack test, which will verify the integrity of that part of the system.
 

Ontario Plumber

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The following advice I give you is based upon the Canadian Plumbing code:

The the vent doesn't necessarily have to remain close to the stack. The vent should be located within minimum 2xPipe diameter (6 inches with 3 inch pipe) and can be a maximum of 3 feet on the vertical plain and 9 feet on the horizontal plain. If the stack that the toilet drains into doesn't receive discharge from anything above and is within 9 feet, then it would be acceptable for the toilet to be vented by the stack.

Hope this helps.
 

hj

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1. There is definitely a crack in the hub and you can see that it continues up and around the top of the hub. THere is NOTHING you can use to seal the crack and it will only keep getting longer and bigger as time goes by and corrosion forces the two sides further apart. The process of replacing the tee, or whatever fitting it is, will require some extensive "remodeling" and might make all your other question moot.

2. It is a MAJOR issue that has to be taken care of before you do anything else. If you try to use a "donut" to connect anything into that hub, the pressure will snap the hub at the crack.

3. It looks like whoever installed it used a "putty/epoxy" compound to make the joint instead of lead and that might be what cracked the hub. You can see that the hub is no longer "tight" to the compound along the upper side.
 
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poppity

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Hoo boy!

Wow! Thanks for all of the advice! But OOF. Yeah. I was afraid of that crack. Which is why I went ahead and opened up more of the flooring and wall, so I (and the plumber who will be handling the real big stuff, cacher_chick) could really see everything. Here's the result:

new_2nd_floor_overview.jpg

This is a much longer story, and if anyone's interested I'll spell it all out. But here's what I think has to happen, if you guys agree. The 2nd floor toilet (and the sink, which is oddly draining into the toilet drain -- that wasn't a vent) is the only thing draining into the stack where that cracked connection is. Since there's another ABS drain -- from the third floor straight past the 2nd floor -- that ties into the stack in the basement, I think I should tie my toilet, tub, and sink into that. In other words, cut out the brass drain as suggested, replace the toilet, tub and sink drains, and tie into the ABS from the 3rd floor instead of the stack on the 2nd floor. Then cap the old cracked connection (even that may be overkill) and leave it.

Since there will now be nothing draining into the stack from either the third or second floors, I see no reason to fix or replace that crack. Yes? No?

I suspect my solution will seem like a no-brainer to all of you. In fact, I can't believe it never even occurred to me. If I had even remembered that the 3rd floor toilet had its own drain, I would've mentioned it earlier. I hope you'll forgive me for not saying so before!
 
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Gary Swart

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WOW! You have many issues here, but two (at least) bring me to this conclusion. You have already stated you're going to have a plumber do the "really big stuff". Now I don't know what you consider the really big stuff, but working with cast iron certainly would qualify. You mention you want to use a "rubber" sleeve. Well that's illegal. Now connections can be made with a similar fitting call a banded coupler, but the plain sleeve is for underground use only. My suggestion is that you leave all of this for the professional. Almost certainly your attempt to DIY will not pass inspection and you'll have to tear out and redo. That means everything you "saved" by DIY will be eatten up and probably more.
 

hj

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You CANNOT just "connect your new fixtures to the drain line from the third floor", period. You don't know how to do it properly, but your plumber will. You still have to seal that crack to eliminate sewer gases.
 

poppity

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Too bad: not DIY anymore!

You CANNOT just "connect your new fixtures to the drain line from the third floor", period. You don't know how to do it properly, but your plumber will. You still have to seal that crack to eliminate sewer gases.

HJ!

Oh, man. Of course! Don't worry. I promise I'm not doing this myself. Not anymore. I just wanted to understand it all so I know how it works, and what has to happen (and maybe purchase some of the raw materials beforehand). I'm having a real plumber do ALL the important stuff. He came yesterday, actually, to scope the scene, and it was immensely helpful to've talked to this forum first.

My original plan to leave the floor and reuse the existing plumbing started wobbling when I found that suspicious crack. I figured it was a dealbreaker, and came here mostly for confirmation of that -- and of course with the hope that it wasn't, that I could make small fixes myself. But when you confirmed the crack was a problem the DIY potential basically vanished.

So! To overly simplify: my plumber is indeed going to tie the new sink, toilet and tub/shower into the drain coming from the third floor. We're gonna cut out all the old stuff, cap the copper that's currently connecting the toilet to the stack, and seal the crack there. Then all the new pipes and vents and stuff are going in!

I can't thank you all enough for your help. You really made it super easy -- and fun! -- to communicate with my plumber.
 
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