Best way to couple tee fitting with pipe for repair area

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Kevin121

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I have 3" PVC for my main drain line and need to cut out a vertical section of it to add a sanitary tee for a water softener drain. I can glue the tee fitting on one end easily but I won't be able to fit and glue the other end at the same time because the pipe is fixed. What is the best way to couple the hub end of the tee fitting with pipe? I haven't seen a coupling that works for both a hub end and pipe end. Should I glue a small stub of pipe into the 2nd end of the fitting and then just use a standard repair (slip x slip) coupling? Any suggestions with using either rubber compression (Fernco) type couplings vs. regular PVC types in this situation?
 

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Terry

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One option is to use shielded couplings, which allow you to just insert from the side, roll the rubber inside over the pipe, slide the outer cover over and tighten it up.

Second option is to use a slip coupling on one side that is glued. They tricky part on that is being quick about it. Certainly doable though.

I prefer doing with the couplings like the ones below. They come in different sizes, so you would want plastic to plastic.

mission_bandseal.jpg
 

Reach4

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Be sure the pipe is supported well from above before cutting out a segment.

You need at least 2 nominal pipe sizes between the U of the trap and the tee for the AAV to avoid a "crown vent". For example, if the trap is 1.5 inch, you need 3 inches or more.
 

Kevin121

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Be sure the pipe is supported well from above before cutting out a segment.

You need at least 2 nominal pipe sizes between the U of the trap and the tee for the AAV to avoid a "crown vent". For example, if the trap is 1.5 inch, you need 3 inches or more.
Just curious what you mean by needing 2 nominal sizes? The drain line from the AAV to the sanitary tee is 1.5" PVC, are you saying I need to adapt to a bigger size pipe on the trap arm, before the tee? Or do you mean the trap arm needs to be at least 3 inches in length before it meets the tee?
 

Kevin121

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One option is to use shielded couplings, which allow you to just insert from the side, roll the rubber inside over the pipe, slide the outer cover over and tighten it up.

Second option is to use a slip coupling on one side that is glued. They tricky part on that is being quick about it. Certainly doable though.

I prefer doing with the couplings like the ones below. They come in different sizes, so you would want plastic to plastic.

mission_bandseal.jpg
So with the shielded rubber couplings option - If I glue the bottom end of the new tee into the pipe (below my cut) first, I would then need to glue in a stub piece of pipe into the other (upper) end of the tee first, and then this coupling would span the pipe above, and the stubbed piece glued into the new tee? I thought they had a type of coupling that has a socket on one end to slip over the hub on the tee, and then the other end will accept pipe, do you know if those exist? That would eliminate the need to glue in a short stub of pipe into the tee fitting? I've tried to illustrate in this updated picture...
 

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wwhitney

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Or do you mean the trap arm needs to be at least 3 inches in length before it meets the tee?
This.

As to the shielded coupling option, the simplest way is to use two shielded couplings, and glue pipe stubs into the top and bottom of your new san-tee, leaving >1" of clean pipe at end of each stub for your shielded couplings.

If it's important to you to have the san-tee as low as possible, you could instead glue the san-tee in place just above the 45, then glue a pipe stub into the top of the san-tee, then use a short pipe segment with two shielded couplings above that.

Note that as the top and bottom of the stack are fixed, there's no way to do this with only one non-standard joint. You'll need two, either shielded couplings, or PVC slip couplings, but the former are much easier to use.

Cheers, Wayne
 

wwhitney

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A Street San tee is also an option to get the lowest possible installation.
That would require getting a Fitting Saver / Rambit type tool, or else start rebuilding lower down. In which case the whole street 45 /street 45 / cleanout wye could be reconfigured in a number of way to provide an additional inlet. E.g. replacing the upper street 45 with a street wye.

Cheers, Wayne
 

Reach4

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Just curious what you mean by needing 2 nominal sizes? The drain line from the AAV to the sanitary tee is 1.5" PVC, are you saying I need to adapt to a bigger size pipe on the trap arm, before the tee? Or do you mean the trap arm needs to be at least 3 inches in length before it meets the tee?
The second one.

We call that pipe 1-1/2 inch tho it is a tad bigger than that. But 2*1.5 = 3 is fine. Nominal/name we call that pipe is 1-1/2.

I would clamp that standpipe somehow to take the strain off of the standpipe from side forces. I don't have a good suggestion for you on how.
 

Kevin121

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This.

As to the shielded coupling option, the simplest way is to use two shielded couplings, and glue pipe stubs into the top and bottom of your new san-tee, leaving >1" of clean pipe at end of each stub for your shielded couplings.

If it's important to you to have the san-tee as low as possible, you could instead glue the san-tee in place just above the 45, then glue a pipe stub into the top of the san-tee, then use a short pipe segment with two shielded couplings above that.

Note that as the top and bottom of the stack are fixed, there's no way to do this with only one non-standard joint. You'll need two, either shielded couplings, or PVC slip couplings, but the former are much easier to use.

Cheers, Wayne
Thanks Wayne. If I glue the new tee into the existing pipe below my cut out section, and then just glue a (new) small stub of pipe into the upper end of the tee, wouldn't I only need 1 shielded coupler to attach the stubbed piece to the main fixed pipe above? I'm not quite understanding why I would need 2 couplers in this case. Any pictures you have may help :) Thanks!
 

wwhitney

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Thanks Wayne. If I glue the new tee into the existing pipe below my cut out section, and then just glue a (new) small stub of pipe into the upper end of the tee, wouldn't I only need 1 shielded coupler to attach the stubbed piece to the main fixed pipe above?
If the pipe above could be lifted up and down, then yes, one shielded coupler would suffice.

But suppose both the top and bottom are fixed, and think about the step just before you intend to add that single coupler. The plastic ends will need to have just an 1/8" gap between them (the thickness of the stop inside the rubber coupler) or a little more. The step just before that was gluing up a PVC joint, which is 1.5" (for 3" pipe) or 1.75" (for 4" pipe) deep. So to glue that joint up, you needed vertical leeway; if the part above is fixed, you couldn't have glued that joint up.

So instead you leave out a section of pipe at least 2-1/2" long. That gives you the vertical range of motion you need to glue up the last glue joint; then you can use 2 couplers to insert that last piece of pipe. You cut your infill pipe section to be 3/8" shorter than the gap between the two pipe ends--1/8" for each stop in the shielded rubber couplings, and another 1/8" for some clearance as you insert the pipe between the two folded back rubber couplings.

And of course, instead of putting in just a single pipe segment as the last step on the stack, your two couplings could be above and below your new fitting.

Cheers, Wayne
 

Kevin121

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If the pipe above could be lifted up and down, then yes, one shielded coupler would suffice.

But suppose both the top and bottom are fixed, and think about the step just before you intend to add that single coupler. The plastic ends will need to have just an 1/8" gap between them (the thickness of the stop inside the rubber coupler) or a little more. The step just before that was gluing up a PVC joint, which is 1.5" (for 3" pipe) or 1.75" (for 4" pipe) deep. So to glue that joint up, you needed vertical leeway; if the part above is fixed, you couldn't have glued that joint up.

So instead you leave out a section of pipe at least 2-1/2" long. That gives you the vertical range of motion you need to glue up the last glue joint; then you can use 2 couplers to insert that last piece of pipe. You cut your infill pipe section to be 3/8" shorter than the gap between the two pipe ends--1/8" for each stop in the shielded rubber couplings, and another 1/8" for some clearance as you insert the pipe between the two folded back rubber couplings.

And of course, instead of putting in just a single pipe segment as the last step on the stack, your two couplings could be above and below your new fitting.

Cheers, Wayne
I see what your saying now, because both ends of the pipe will be in-line with each other vertically and I don't believe there will be any movement possible (although the top section may be somewhat movable once cut) so in order to insert pipe 1.5" into the hub end will cause interference from the upper end being in the way. It's an interesting (and frurstrating!) problem. So the Fernco shielded rubber couplings are fine to use on a vertical section of pipe that gets infilled (as opposed to horizontally) with no leak concerns? I believe I will somehow have to clamp/support the Air-gap fitting as well to prevent sideways movement as Reach4 suggested. Any suggestions on doing this?
 

John Gayewski

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Split ring clamps and all thread with a sammy.
I see what your saying now, because both ends of the pipe will be in-line with each other vertically and I don't believe there will be any movement possible (although the top section may be somewhat movable once cut) so in order to insert pipe 1.5" into the hub end will cause interference from the upper end being in the way. It's an interesting (and frurstrating!) problem. So the Fernco shielded rubber couplings are fine to use on a vertical section of pipe that gets infilled (as opposed to horizontally) with no leak concerns? I believe I will somehow have to clamp/support the Air-gap fitting as well to prevent sideways movement as Reach4 suggested. Any suggestions on doing this?
 

Kevin121

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It may not be shown as well in the picture, however the main stack is not tight to the stud wall behind it, however I will likely want to support both the air-gap and the trap to the metal studs. Can I can use either 22.5 or 45 degree elbows on the trap arm to get out from where the stack is to be in closer to the studs? Or do I need to keep the trap arm as one straight piece?
 

Reach4

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It may not be shown as well in the picture, however the main stack (again) is not tight to the stud wall behind it, however I will likely want to support both the air-gap and the trap to the metal studs. Can I can use either 22.5 or 45 degree elbows on the trap arm to get out from where the stack is to be in closer to the studs? Or do I need to keep the trap arm as one straight piece?
Without looking at a picture, the trap arm must stay horizontal until vented. After being vented, you can go down at any angle.

Horizontal in this case is actually usually a 2 degree downward slope.
 

Kevin121

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Without looking at a picture, the trap arm must stay horizontal until vented. After being vented, you can go down at any angle.

Horizontal in this case is actually usually a 2 degree downward slope.
Maybe I didnt state that correctly, Yes it would still slope downward toward the drain, but would have 2 turns to swing in toward the wall to where the trap and air gap would be supported by. I believe I read somewhere that the trap arm can turn up to 110 degrees but just looking for some kind of confirmation if it can turn horizontally.
 

wwhitney

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You can turn the trap arm "in plan" (as seen from above) with a 22.5 or two, or a 45 or two, sure. Just maintain the 2% slope throughout.

Cheers, Wayne
 

Kevin121

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Here is what I picked up at the local hardware store (both a shielded no-hub and a no-hub coupler). It seems like the Flexible coupler without the shield probably should be avoided? Will this shielded No-hub coupler work good for PVC to PVC? I thought I had read somewhere that these no-hubs are only for Cast Iron pipes so I wanted to check. The rubber wall on the no-hub coupling is much thinner than the flexible coupling. Thanks again!

2022-01-26 19_11_26-Coupler.jpg
2022-01-26 19_05_48-Coupler.jpg
2022-01-26 19_04_27-Coupler.jpg
 
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wwhitney

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Neither of those is the proper one. The flexible coupling is only for use underground, and the no-hub is for cast iron, which is a different diameter from plastic in the 3" trade size.

You need a Fernco 3005-33 or Mission P-300. It will have a shield like the no-hub, but thicker rubber like the flexible coupling.

Cheers, Wayne
 
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