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Adding a wye to a 4" hub & spigot stack

tlowc34
tlowc34 Member Posts: 75
My house is 92 years old with a kitchen reno done in the early 80s. All of the DWV are cast iron hub & spigot, except for the 80s reno. When they did the update, they moved the kitchen sink and dropped a 1-1/2" PVC drain down from the kitchen sink/garbage disposal. It currently blocks the operation of the basement window. Garbage disposal failed and wife hates the double sink so I ordered up a new single drain deeper sink and wanted to improve the way the plumbing is run to restore window functionality and improve drainage/prevent siphoning when going to a single sink by adding an AAV. The plumbing is all run to the right, but there is a whole mess of steam heat plumbing there. Would seem to make sense to move to the vertical stack on the left that is in good shape. I think I could cut it and add a 4x2 no hub wye and run it that way. Attached a pic of my previous repair as proof of ability to work with no-hub. Thoughts?





Comments

  • pecmsg
    pecmsg Member Posts: 1,870
    edited September 2020
    The only concern is that cast iron stack. Get it supported properly before cutting!

    Also where's the Vent going up?
    STEVEusaPAmattmia2MikeL_2delta T
  • JUGHNE
    JUGHNE Member Posts: 8,142
    Is there a reason the 2" iron riser could not be reused?
    You could come away from the basement wall with your pipe up between the floor joists and then over to the extended 2".

    That would get you pretty good clearance for the window to swing up.

    Yes, that 4" CI stack can get pretty heavy and tend to slide down, maybe cracking any tee that might be hidden.
  • tlowc34
    tlowc34 Member Posts: 75
    edited September 2020
    Didn't think of the cracking concern, but knew about the weight. Stack goes to the roof through a 2nd story bath. I was thinking I could use a riser strap and support it either temporarily with 2x4's under the strap or permanently at the floor joist area:

    Here's a better view of what I'm working with around the existing 2" riser:


    Maybe I'm just being too OCD, but I hate the inefficient clumsy routing. I don't know if there is a word for that in the trades. Crazy routes that use multiple bends, joints, bushings, etc. Like Don't take a 4" wye and then put a bushing on it, use a 4x2 wye that doesn't need a bushing.


  • tlowc34
    tlowc34 Member Posts: 75
    @pecmsg it doesn't currently have a vent. I was going to use the air admittance valve, since I can't sneak a loop up over the water level of the sink. Thoughts?
  • pecmsg
    pecmsg Member Posts: 1,870
    I ran a 1 1/4” vent horizontal until I could go up. 
  • mattmia2
    mattmia2 Member Posts: 2,643
    edited September 2020
    You certainly can cut in to the CI, but it will be a whole lot easier to re-route that current pipe with PVC even if you have to come over the steam pipes in the joist bay then back around. It probably once had a vent in the basement that was removed during the renovation. Think long sweep fittings and 45s in the drain section as much as possible. Street ells might get you in to some of the tight corners too.

    If you actually want to come across to the CI stack by drilling the joists you will have to use several sections and couplers to get it in place which in itself will be a little ugly.
  • Danny Scully
    Danny Scully Member Posts: 1,319
    @tlowc34, Cut the 2” gal below the window, then come up between the 2 windows.
    JUGHNEmattmia2tlowc34
  • hot_rod
    hot_rod Member Posts: 14,552
    I guess it depends on how much better you want it to look? I agree with a riser clamp and some all thread to the joist above for support.
    Those new carbide sawzall blades are amazing and would zip thru that cast like butter, almost :) There have been a few demos of those new blades on IG recently. A few no hub bands and away you go.
    I'd be reluctant to put a snap cutter on old cast, I have had it crush before it snaps.
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • tlowc34
    tlowc34 Member Posts: 75
    @hot_rod I had trouble with the carbide stuff on the no-hub - I think the coating gummed up the blade. Might work better on the uncoated old stuff. I always just break out the cutting wheel on an angle grinder and finesse it to a marked line.
  • tlowc34
    tlowc34 Member Posts: 75
    I might just go the really OCD route and fix the lazy rerouting of the steam lines near the 2" riser. The radiator in the kitchen has been moved twice and they just patched in more and more elbows and unions that are complicating the issue.
  • Jamie Hall
    Jamie Hall Member Posts: 15,340
    I don't usually slightly divert a thread, but in this case maybe someone can help... I have a situation where I need to connect new waste drainage (probably ABS, 3 inch) to an old cast iron 4 inch hub... in which there is a 4 inch stub about 2 inches long sticking out of lead (yeah, really) DWV. Which was beautifully wiped into the hub (those old guys -- around 1910) -- really did a truly beautiful job).

    Suggestions? I'm thinking Fernco on the lead stub and new DWV...
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England.
    Hoffman Equipped System (all original except boiler), Weil-Mclain 580, 2.75 gph Carlin, Vapourstat 0.5 -- 6.0 ounces per square inch
  • tlowc34
    tlowc34 Member Posts: 75
    edited September 2020
    Wouldn’t it make sense to go 4” lead > fernco > 4” pvc > 4”-3” reducing pvc coupling > 3” pvc/abs 
    that way any lengthwise force doesn’t collapse the 3” -4” reducing rubber coupling?
  • tlowc34
    tlowc34 Member Posts: 75
    edited September 2020
    There is the type that has a metal shield, but it looks spendy and there still isn't any lip for the end of the 3" pipe to rest against. It would all be friction grip on the OD to hold it in place.



    https://www.ferguson.com/product/fernco-4-x-3-in-cast-iron-and-plastic-flexible-coupling-f105643rc/_/R-3083399
  • JUGHNE
    JUGHNE Member Posts: 8,142
    IIWM, I would drill out the lead pour in the hub.
    1/4" x 12" drill bit long makes it easy, hook out the lead and oakum with heavy wire (#9).
    Then use a 4 x 3 Fernco donut to put the PVC directly into.

    Give or sell the lead to an ammo reloader.
    tlowc34
  • tlowc34
    tlowc34 Member Posts: 75
    edited September 2020
    @JUGHNE I thought about this approach, but how do you stop the 3" from continuing to push into the 4" lead past the donut? Is there a positive stop on the donut? Or is it unnecessary?

    I used the donut for 4" no-hub to 4" hub & spigot and the no-hub banks on the bottom edge of the hub.
  • Jamie Hall
    Jamie Hall Member Posts: 15,340
    Bravo! I knew you folks would have good ideas. Onwards... hadn't thought of using the lead for ammo reloading... with the state of ammo supplies these days, not a bad idea at all!
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England.
    Hoffman Equipped System (all original except boiler), Weil-Mclain 580, 2.75 gph Carlin, Vapourstat 0.5 -- 6.0 ounces per square inch
  • JUGHNE
    JUGHNE Member Posts: 8,142
    I place a bury mark with a sharpie on the pipe to avoid that.
    Usually have to taper the end of the pipe and wire lube both the donut, hub and pipe. Sometimes just install a short piece, some need a block of wood and sledge hammer on the short PVC.
    Hub castings can vary a fair amount, seldom to big.

    For one that was too loose for donut, there is a PVC hub adaptor.
    Used oakum and then "Plastic Lead" for that one.

    Jamie, my father plumbed his house in the early 40's.
    Lead was in short supply, he used some form of cement where the lead pour would have been. Still holding today.
    But if you flex the joint at all the cement cracks, found out moving a 1 1/2" drain and then went to the donut.
    tlowc34
  • GW
    GW Member Posts: 3,990
    I’ve done this a bunch, hit me if you need more ideas
    Gary Wilson
    Wilson Services, Inc
    Northampton, MA
    www.wilsonph.com
    [email protected]
  • dopey27177
    dopey27177 Member Posts: 433
    The minimum drain size for a kitchen sink is 2"
    The trap should be 2" and the drain size 2". Additionally, there should be a vent for the drain line of the sink.

    Not all codes allow air release fittings below the flood rim of the sink.

    In Florida the air release fitting can be installed under the sink.

    Jake
  • EBEBRATT-Ed
    EBEBRATT-Ed Member Posts: 8,503
    1 1/2" is minimum for a kitchen sink around here.
    delta T
  • Intplm.
    Intplm. Member Posts: 1,282
    The code in my neck of the woods changed from 11/2 to 2 inch some years ago. One of the reasons was to help for a better performing drain if a disposal was ever to be added.
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