Kitchen drain help. 😫

brandonf

I'm in the process of moving some cabinets around and adding a new countertop and sink. It's a 100 year old house with a cast-iron stack. Someone threw a rubber fernco over the female end of the cast iron that comes out of the wall and fit it to a PVC reducer down to inch and a half. I was tempted to leave it alone since it always worked but I noticed it's leaking at the rubber. I need to figure out how to properly transition the cast to PVC so I can set up my sink drains? I also learned never to pour grease down a drain. Thanks in advance.

HVACNUT

I'm not sure but I'd say the PVC side is ok if it's not just the bushing but a short piece of pipe as well to butt against the cast.
I believe a "No Hub" coupling would work instead of the furnco but wait for others to respond. There might be a better, different way to go about it altogether.

Danny Scully

Can you see the pipe in the basement? I would strongly consider cutting it there and starting over with PVC. You would use a No-Hub clamp as @HVACNUT suggested, not a fernco.

Intplm.

Since the cast iron is not leaking there are a few different things you can do directly in or at the CI hub.
Research a "manoff", or a "push gasket". The push gasket is the least amount of work and are usually available at a supply house.

While you are at it. Update your pipe size to the sink drain from inch and a half to two inch. Doing that will bring the job up to code and make for a better job in the long run. Less chance of clogs, better flow.

If you don't want to use a manoff or push gasket, check to see if you have enough room behind the bell on the cast iron pipe to install a no hub clamp. If you do, cut it off and install a no hub clamp there. No hub clamps work on pipe and not on the outside diameter of a cast iron bell so do not try that . It will not work. It will leak.
If there is a sanitary tee or (TY) inside the wall (and I'm thinking there is,) you will not have enough room to install a NH clamp.
You will need to cut the TY out and replace it with a PVC (TY). This can be a lot of work.

Lastly. You can install a reducing fernco coupling over the hub of the cast iron, similar to what you had before, but not quite the same. The outside diameter of a cast iron hub is not a standard pipe size offered by fernco but ferncos do fit over the hub. So if you go this route you will need to tighten things up a bit on the cast iron hub to get a good connection.
@brandonf
Good luck. Hope this helps.

Danny Scully

1-1/2” is actually the minimum pipe size for a kitchen sink drain @Intplm., as well as shower drains. Also, ferncos aren’t up to code as they have no stops.

Intplm.

Danny Scully said:

1-1/2” is actually the minimum pipe size for a kitchen sink drain @Intplm., as well as shower drains. Also, ferncos aren’t up to code as they have no stops.

Not in my neck of the woods @Danny Scully . 2" is the required pipe size for a kitchen sinks updated many years ago from 1-1/2", and shower drains have always been 2". But I do agree with you as to the your fernco information. They have never been accepted for the reason you mentioned.
If @brandonf wants my opinion as to which is the best connection to use in his situation. I would say use the manoff fitting. Installing the manoff would be the most work, but It would be the biggest improvement from them all. However all that I mentioned are viable options.

Danny Scully

Fair enough @Intplm. Where are you located?

Intplm.

Ct. RI border . Where are you @Danny Scully

ChrisJ

I'm not a plumber but from what I recall on my area the vented piped must be 1 size larger than what the kitchen sink is plumbed in and that must be 1.5" minimum. So a 2" vented pipe.

This is to keep it from siphoning the trap I believe.

I call @Charlie from wmass to the stand on this one....

Danny Scully

Long Island @Intplm., and that’s a negative @ChrisJ, at least according to the national (and international) standard plumbing code. An 1-1/2” vent is good for 8 drainage fixture units. A kitchen sink equals 2 drainage fixture units.

hot_rod

Fernco does make transition couplings for just about any piping materials. The outside of a cast iron bell isn't usually all that smooth to make a good connection?

Charlie from wmass

Vent with no waste flow can be 1 1/4" for up to a 2" drain. In Massachusetts we can only transition once in material. Kitchen can be 1 1/2" unless it serves several sinks. Some areas the local code does call for 2". A mission coupling is the best transition for cast iron to PVC unless you can pour a lead joint.

brandonf

https://www.supplyhouse.com/sh/control/product/~product_id=1056-415

I ordered this reducing coupler. I'm kind of stuck because this is on a 2nd floor so full replacement is a little too big of a job at this point. Now after reading the comments I should have ordered one with a 2" side instead. Considering how clogged the old one was from puddling and grease from being pitched wrong this would probably work ok. I'm considering adding a second clamp on the CI side.

Charlie from wmass

Non shielded couplings are only for hacks. Sorry but that is my 27 years as a licensed plumber opinion. If you are need to go to 1 1/2" from 4" you get a 4" shielded coupling (the ones with a stainless steel band) and use a plastic reducing coupling. I will need to look at the photos further.

Charlie from wmass

The large pipe is 3" cast iron from the photo with the tape measure

brandonf

"Charlie from wmass" that was kind of what was there before except with a fernco instead of the shielded coupling. My problem with a shielded coupling and separate reducing coupling is it may not allow for a good enough pitch and I don't want a bunch of puddling at that connection like what happened before. The trap on the sink is going to be about a foot away from this thing. How much pitch should I have? 🤔

Charlie from wmass

1/4" per foot of run

Intplm.

brandonf said:

https://www.supplyhouse.com/sh/control/product/~product_id=1056-415



I ordered this reducing coupler. I'm kind of stuck because this is on a 2nd floor so full replacement is a little too big of a job at this point. Now after reading the comments I should have ordered one with a 2" side instead. Considering how clogged the old one was from puddling and grease from being pitched wrong this would probably work ok. I'm considering adding a second clamp on the CI side.

That's fine @brandonf but change that to a 4x2 inch if you want to update the size of the drain.
Slide the new pvc pipe toward the back of the cast iron spigot when you install it, but not to far that it gets in the way of the run if a "TY" is in the wall. This will be much better than what you had before.

Intplm.

@Danny Scully Some time when I get down to the beach on a clear day I can see Long Island. We are very close as the crow flies.
Amazing that the little distance of Long Island sound can have such a big difference of code requirements.

brandonf

Does anyone think I need to put some sort of a sealer on the big side since the cast iron is a bit rough? 🤔

Intplm.

You can if you like. Some use clear silicone.
I usually just clean the cast to as smooth as possible and then tighten the clamp. You are installing the 4" side on the outside diameter of the cast iron hub? Right?
Just be sure to tighten it down real well. Just be careful not to strip the clamp from over tightening.

JUGHNE

Was a Fernco donut considered?
IMO, less chance for leaks on clamps.
They make all combinations of sizes.

delta T

One cause of leaks with Ferncos and no hub coupling is under or over tightening the clamps. Make sure you get a 60 in-lb torque wrench for the bands.

https://www.supplyhouse.com/Jones-Stephens-T60060-Ratchet-Torque-Wrench-w-Built-In-Reversing-Lever

brandonf

> @JUGHNE said:
> Was a Fernco donut considered?
> IMO, less chance for leaks on clamps.
> They make all combinations of sizes.

From what I saw the donuts are only effective on vertical connections. They look like they would eventually seep on horizontal connections.