Can I change cast iron out for PVC?

[xdeaconx]

Hi guys,
2 years ago we had an ejector pump put in the basement to rough out a bath down there, and the plumbers ran most of the work in PVC. Except for the lateral line that feeds in to the soil stack. That they did in cast iron. So now I've got my basement ceiling open and have discovered the upstairs shower drain, It's a real hack job (I'll have to sister up the joists someone plowed through). I want to re-route the drain for the shower along the wall in PVC. Couple of questions.

Is there any reason why I can't change that lateral section of iron out for PVC?
What diameter should that section be? What is the best way to tie into the existing iron?

I plan on replicating the layout there, but add an wye at the end to receive the shower drain. Photos show what I'm planning. Any issues or things to watch out for?

Thanks
dieter

 

[Terry]

You can change that to PVC, make sure the 2" cast iron going up through the floor is supported.

The sewage pump piping should run into the 4" stack by itself.
You can't combine other fixtures on that 2" run.

So........cut in a second 4x2 fitting on the main stack, one for the pump, and one for the other plumbing in the home.
When the pump runs, it dumps gallons and gallons all at once.
When that happens, you are no longer sized correctly for the other fixtures.

 

[Sponsor]

 

[xdeaconx]

You can change that to PVC, make sure the 2" cast iron going up through the floor is supported.

The sewage pump piping should run into the 4" stack by itself.
You can't combine other fixtures on that 2" run.

So........cut in a second 4x2 fitting on the main stack, one for the pump, and one for the other plumbing in the home.
When the pump runs, it dumps gallons and gallons all at once.
When that happens, you are no longer sized correctly for the other fixtures.

Man, I'm glad I posted up. Why didn't they just do it right the first time. Are there any constraints on how it gets plumbed in? I'm thinking something like this (photo below).
Are there special transitional PVC fixture used with plastic lead that join PVC to iron?

 

[Terry Love]

Yes, you can run it that way, or you can cut some cast off shorter from the upper floor, and use the upper wye for the second floor and the lower wye for the pump.
That way you are not crossing your pipes, and it will look cleaner.

 

[hj]

You can also just change that 4x2 Y, into a 4x3 or 4x4 and connect the pump and tub into the single fitting with reducers for the two lines. However, you CANNOT slope the tub drain as much as your picture shows, unless you provide a vent near the "P" trap. This is a case where WHAT you want to do is possible, but the WAY you do it will determine whether it is correct or not.

 

[xdeaconx]

You can also just change that 4x2 Y, into a 4x3 or 4x4 and connect the pump and tub into the single fitting with reducers for the two lines.

I'm having a hard time visualizing this, what would the fixture end up looking like?

However, you CANNOT slope the tub drain as much as your picture shows, unless you provide a vent near the "P" trap. This is a case where WHAT you want to do is possible, but the WAY you do it will determine whether it is correct or not.

Understood, what is the pitch per foot I should be aiming for? And if it's too steep to connect as show will this work? pic below

 

[xdeaconx]

bump with revision to plan.

 

[xdeaconx]

HJ i'm going to try and tackle this this weekend. can I use a 45 or 90 to drop the shower drain to meet the lateral line as described in photo above?

Also how does this look for the 4x4x4 stack fitting layout (photo below)? Is this what you were talking about when you said hook both shower and pump into stack using reducers?

thanks

 

[xdeaconx]

Anybody have any input about the plans above?

 

[Terry]

Like I said above, you would spend less money, and the job would look cleaner, if you retained the 4x2 cast iron wye you have on the 4" stack, and you add a second 4x2 wye above it.

The makes a shorter distance from the pump to the stack.

It also makes an easier cut on your 4" vertical stack.

How many plumbers have tried to snap off less then an inch to insert the slightly longer 4x3 wye to replace the existing 4x2 wye. It's almost impossible.

It's much easier to move up the distance that the second fitting would take.
This way, you would buy one more 4" no-hub coupling and a 4x2 cast wye.

The solution in your last drawing means adding a 4x2x2 wye, which they don't make, you would have to bush the end of a 4x2 wye, and adding a 4" 45.

By adding a second 4x2 fitting on the vertical stack, you can then run everything in 2".

 

[xdeaconx]

Like I said above, you would spend less money, and the job would look cleaner, if you retained the 4x2 cast iron wye you have on the 4" stack, and you add a second 4x2 wye above it.

The makes a shorter distance from the pump to the stack.

It also makes an easier cut on your 4" vertical stack.

How many plumbers have tried to snap off less then an inch to insert the slightly longer 4x3 wye to replace the existing 4x2 wye. It's almost impossible.

It's much easier to move up the distance that the second fitting would take.
This way, you would buy one more 4" no-hub coupling and a 4x2 cast wye.

The solution in your last drawing means adding a 4x2x2 wye, which they don't make, you would have to bush the end of a 4x2 wye, and adding a 4" 45.

By adding a second 4x2 fitting on the vertical stack, you can then run everything in 2".

Thanks for the heads up Terry, I didn't relize that the 4x3 was slightly longer. I thought I could just switch them out. This sounds like the best way to proceed.

I do have just a few more questions.
First does the photo in post #6 look right, concerning connecting the tub drain with the lateral line to the stack?
Also what is the best way to brace the 4" soil stack while I make the cuts?

thanks again for all the help.

 

[SewerRatz]

I see you are in Chicago, a little point to Chicago Plumbing code. You can not use no hub couplings or ferncos in Chicago. You have to use a proper transition fitting. That no hub fitting on your stack has to come out and you need to use a sission fitting there to be able to install a hub fitting. Since you are going to need to change the fitting to a hubbed fitting you can put in a double wye in the place of your nohub wye fitting. This way you will be able to keep your current drains draining into the stack and tie in your ejector pump into the other side of the double wye. Also make sure your pump does not receive any storm or rain water.

 

[xdeaconx]

Dang! So one more thing not done right. At least I'm getting the real deal here.
So does that mean I'm going to have to lead the joints now? Also how does that sission fitting work? does it slip inside the stack?

There is a wall on the right hand side of the stack. Do they make double wyes that are set 90 degrees instead of 180?

Where can I get these sission fittings, Shilvocks?
Nope no storm water in the ejector.

Thanks for the heads up Phil

 

[SewerRatz]

Any plumbing supply in Chicago will have the sission coupling. the hub is twice as deep than a normal hub so you can slid it up and out of the way to insert a fitting in the same line then it slides back in place. there is a bump midway down the hub to catch the oakum so you can still pack the joint properly to lead it up. Let me have a look in my cast iron book for the fitting that you need.

Ok here is the fitting its a 4 x 2 wye with a left hand side tapped inlet. If you want the inlet to be on the right hand side then ask for a SV 57A

 

[xdeaconx]

Much appreciated (sorry for calling you Phil, that was the name in your sig, now it says Ron. So I don't know what to call you haha).
So the "c" section of the sission fitting (from above photo) slides into the lower half of the vertical stack. Then you put your wye fitting in and slide the sission up to meet the fitting. What keeps the sission from sliding back down? The lead and okum?

I don't have any leading supplies. Would I be able to use plastic lead?