Can I plumb a rear-outlet toilet like this?

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Sjlammer

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Hello,

Long time lurker. I have found this forum to be a great resource over the years. I am an water supply engineer, understand fluid mechanics, have done a fair amount of plumbing work for an amateur.

I was looking at friends new house and they had a rear outlet toilet plumbed into the waste stack.

I've looked online and I can't see where anyone is plumbing a rear outlet toilet like this so I wanted to run it by the experts.

Basically the setup I saw was rear outlet toilet, toilet flange, closet bend (turned to provide pitch), santitary tee cut into the waste stack. I went and bought the fittings to lay it out to make it easier to visualize. my gut says the inside miter of the closet bend is too tight to lay on it's side. If I made the decision on my own, I would opt for a long radius bend.

What do you guys think? I

Thanks for your help.

photo a.jpgphoto 1.jpgphoto 2.jpgphoto 3.jpgphoto 5.jpg
 

hj

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The problem with that closet bend that it is a "4x3 reducing" fitting, which means there will ALWAYS be water standing in the 4" section. You need a 4" closet bend. If you use a "long sweep" fitting, the wall is going to have to be much thicker to accommodate it.
 

MajMetro

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I'm trying to work out something similar in my project. Not really happy about using a rear-outlet toilet, but "in theory" it solves most of my problems.

With no experience regarding these rear outlet units, would a toilet such as the Saniflo be able to flush cleanly through a 3 in horizontal run utilizing a 3" "long sweep" 90 to a 3x2x3 sani-tee, much like the configuration above?

I like the looks of the Kohler Barrington as it's a much "cleaner" finish install. Do any of the floor mounted, rear outlet units (like the Kohler) have a 3" outlet or are they all 4"?

Sounds like the rear-outlets tend to leak more often than the standard floor outlet. At least that's my impression of what I've read on the web.

Seems like there's hardly ever a bullet-proof solution.
 
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hj

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NO TOILET has a "4 inch outlet". The 3 or 4 inch specification applies to the pipe and flange the toilet attaches to. A back outlet toilet does not have to leak more often, it depends on whether you use the proper seal between the bowl and the flange.
 

MajMetro

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Okay, so what I guess I was referring to was the Kohler Barrington requires a 4" rough-in. Please forgive me for being such a novice, but I'm concerned like you mentioned above that we do not want to have water standing in any part of the outlet waste drain line. So would a 4x3 Reducing Closet Flange solve this issue? Any comment on running the waste drain horizontal for about 2 feet before it goes vertical? (I'm limited to using 3" waste drain piping for the toilet.)

Kohler_barrington_spec.jpg
 
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Terry

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That 4" rough-in is measured from the floor. Some are 4-1/4"
Just as a standard floor rough is 12" from the back wall.
A standard 4x3 closet flange works for those, and closet bolts. They do make rubber washers for the wall seal, or reinforced wax seals that will say on the box that they are compatible for a wall seal.
Your standard wax is not compatible.
 

WJcandee

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I'm trying to work out something similar in my project. Not really happy about using a rear-outlet toilet, but "in theory" it solves most of my problems.

Before we get too far along, and you commit to using what I would loosely call a "non-standard" fixture in your project, why don't you share with us what you think the problems are that it solves. Maybe we can be helpful in that regard. If you're enough of a noob to confuse the rough-in with the outlet size, maybe we can help.
 

Terry

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If you install a toilet on that stack, and there is a bathroom using it from the floor above, you will need to vent between the toilet and the stack. Otherwise, the upstairs toilet is going to make the lower toilet lose water.
 

MajMetro

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I started a different thread a few days ago, but since I'm here, I'll see if I can finish this up.

Bathroom layout. Room is on 2nd floor of 2 story, post and beam where there is no ceiling/floor joists between 1st and 2nd floors. Will need to run vertical waste drain lines on exterior wall. No bathroom below, so will connect to main waste drain in crawlspace.

bathroom_v2 (Small).jpg

Will this work with the Kohler Barrington rear outlet toilet? How about the Caroma Sydney or Saniflo 007? (The green is a vent only.)

Horizontal_drain (Small).jpg

Thanks for taking the time to comment on all of this..

Mario
 
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MajMetro

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Hey there Sjlammer,

What did you finally decide to do? Which toilet are you using? How'd it work out??

I have "zero" experience with the rear outflow units, so I'm curious as to others' experiences.
 
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