Connect to an existing PVC drain line

[semto]

Hi,
I am in the process of adding a shower to a basement bathroom. I need to connect the 2'' shower drain line to an existing 3'' drain that runs horizontally under the slab. I am trying to use a 3x3x2 wye and connect it to the 3'' pipe using a Fernco rubber coupling on one side and a cemented joint on the other. Before I cut into the existing line I made a mock up of the situation as in the picture, which does not seem to work. Is there any trick to get the wye in place? There is no play in the existing line.

My other option would have been to use two rubber couplings, one on each side of the wye. Unfortunately, though, there are two other couplings, about 15'' apart, on both sides of where the wye is to go. This does not give enough space to slide the couplings out of the way before sliding the wye in place.

Any help is much appreciated!

 

[Smooky]

Maybe you could put a no hub cast iron fitting in there. See what you think:
https://www.ferguson.com/product/-3...mk/_/R-46158?skuId=46158&typeAheadSearch=true
3 x 3 x 2 in. PVC DWV ST Reducing Wye
https://www.ferguson.com/product/-3...uId=19891&p_36213=&p_19891=&p_2971=&p_298701=

http://www.homedepot.com/p/2-in-PVC-DWV-45-Degree-Spigot-x-Hub-Street-Elbow-C48062HD2/100343359

 

[Sponsor]

 

[Jadziedzic]

Assuming the other couplings are fully accessible, why not cut out the other couplings, add longer stubs to your wye, and use the rubber couplings at those points?

 

[Standardairconditioner]

First of all, good job on the pic. We love pics! So many new members come here without pics or diagrams, and then wonder why they don't invite any answers to help them.

At least you figured out that you need a rubber coupler. Many DIY's almost never realize that installed DWV pipes are very rigid and almost can't flex, especially when they are 3" and more.

Unless you are willing to remove more pipe to be able to glue one side, you're going to have to use two rubber couplers. You said there were others already installed nearby, you'll have to remove those too and re-do those ends.

Can you show us a pic of the actual area you want to pipe, zoomed out enough so including those said nearby couplers?

 

[hj]

The first question would be whether YOU should even be doing it. You CANNOT just insert a fitting and then connect the drain to it. The drain/trap MUST have a vent which you do not mention, or indicate you have considered it.

 

[semto]

Maybe you could put a no hub cast iron fitting in there. See what you think:
https://www.ferguson.com/product/-3...mk/_/R-46158?skuId=46158&typeAheadSearch=true
3 x 3 x 2 in. PVC DWV ST Reducing Wye
https://www.ferguson.com/product/-3...uId=19891&p_36213=&p_19891=&p_2971=&p_298701=

http://www.homedepot.com/p/2-in-PVC-DWV-45-Degree-Spigot-x-Hub-Street-Elbow-C48062HD2/100343359

Thanks for your suggestion. It hadn't occurred to me that I could use cast iron. I will go out to the supply house today and see what they have. With the other piece (the reducing wye) I am thinking that I would run into the same problem.

 

[Standardairconditioner]

With the other piece (the reducing wye) I am thinking that I would run into the same problem.

Smooky is trying to tell you to find a Wye that doesn't have a bell ends on it, so this way the rubber coupler will slide directly on the Wye.

The Wye in your photo has bells on the ends, and it's why you have to glue a small length of pipe on it.

 

[Smooky]

With the PVC wye you could add a short section of pipe to the hub end and then if there is enough space clamp both ends. A picture of what you are working with in the hole would help.

 

[semto]

Thanks all for the replies. Yes, I do understand that what I need is a wye without the hubs. I am going to look for these at a supply store later today.

I have attached a picture of the area. The problem with cutting out the other couplings is that one is under the room next door making it hard to access without breaking more concrete, and the other is a wye meaning that if I remove it I have two new connections to worry about.

hj, there is already a wet vent in the bathroom used by the sink and toilet as you can see. But thanks for pointing that out.

 

[Terry]

You will need two of these, and go ahead with the PVC fittings and pipe. Either a 45 or a long 90 where you go vertical.

 

[Standardairconditioner]

You got the slab removed, so this is your chance to re-do it right.

If you need more horizontal to slide that rubber coupler in, you will chop off that Wye-Tee and Wye on the left of your shower drain, and re-do those.

I know your intention was to save them, but Pvc is cheap, soft to cut, and easy to glue.

 

[semto]

Standard you are right. I did think about that. However, since it is very difficult to move/flex these pipes, I am afraid I would not be able to make good joints in rebuilding it.

I am wondering if it would be ok to go horizontal from the ptrap towards the wall, do a 90 degree turn, and connect to the vent. There would be enough space there to insert a wye with the fernco couplings.

 

[krik]

I am wondering if it would be ok to go horizontal from the ptrap towards the wall, do a 90 degree turn, and connect to the vent. There would be enough space there to insert a wye with the fernco couplings.

You'd use a santee not a wye (which gives you more room to work with) unless that diagonal piece is less than 45 deg up. But if you're getting this inspected it might fail regardless - the current 2" vertical vent to 3" horizontal is a santee, which is the wrong fitting for that change of direction. You'd need to change it out for a wye + 45, but there's no room unless you also move that horizontal wye downstream some more.

 

[semto]

You'd use a santee not a wye (which gives you more room to work with) unless that diagonal piece is less than 45 deg up. But if you're getting this inspected it might fail regardless - the current 2" vertical vent to 3" horizontal is a santee, which is the wrong fitting for that change of direction. You'd need to change it out for a wye + 45, but there's no room unless you also move that horizontal wye downstream some more.

Thanks for your reply. The diagonal piece is just about 45 deg (a little less). The sanitee is an existing piece from when the house was built in the 80's. If I use the wye +45 to connect to the vent just above the sanitee, should I not be ok because the sanee was existing? Thanks!

 

[krik]

Thanks for your reply. The diagonal piece is just about 45 deg (a little less). The sanitee is an existing piece from when the house was built in the 80's. If I use the wye +45 to connect to the vent just above the sanitee, should I not be ok because the sanee was existing? Thanks!

My sense is no - you'd need to bring it up to code. Something to check out with the code enforcement office before you make changes.

 

[Smooky]

If the other plumbing was approved in the past or if it is existing and functioning with out problems you could just leave it as is. When you install the new Wye it will be held in place with the shielded couplings. If it is inspected and the inspector turns it down, it will not be that difficult to remove the coupling and cut out the other fittings and do it the right way. It is up to you. It is worth a try at the most they will charge a reinspection fee. Once you make the first cut and start on it, it want be as bad as you are imagining especially if you put it together with removable couplings. Buy plenty of fittings, most places will let you return what you don't use.

 

[Reach4]

When you install the new Wye it will be held in place with the shielded couplings.

Since the couplings will be buried, they would be permitted be unshielded, right? I wonder if that would make install easier in a tight situation.

 

[semto]

I figured it would be easiest to go horizontal from the ptrap and connect directly to the vent just above the existing santee. Would there be any problem with that? I am going to take my chances with the santee and if it is not approved I guess I would know then exactly what they would expect. Thank you all for your input!

 

[BillTheEngineer]

For you Wye install a reducing street wye would make it easier. Could glue a short nipple in the socket end and than use two rubber coupling.
http://www.lascofittings.com/products/D603-337

 

[semto]

For you Wye install a reducing street wye would make it easier. Could glue a short nipple in the socket end and than use two rubber coupling.
http://www.lascofittings.com/products/D603-337

Thanks for the reply. Just to confirm, you are referring to connecting with a wye at the vent right? And this is an ok way of doing it as opposed to connecting on the main line? Thanks!