PVC drain into ABS waste stack

Discussion in 'Plumbing Forum, Professional & DIY Advice, Tips & ' started by stonypaw, May 11, 2008.

  1. stonypaw

    stonypaw New Member

    Messages:
    5
    I am running a 2 inch PVC drain line from a washing machine to a 3 inch ABS waste stack. What is a proper way to make this transition? I am thinking either a 3 inch flexible Fernco sani-T, or a 3 inch PVC sani-T with 2 short stubs and 3 inch to 3 inch "Plumb Qwik" Fernco sleeves, connecting the PVC stubs to the ABS.

    Attached Files:

  2. jimbo

    jimbo Plumber

    Messages:
    8,997
    Location:
    San Diego
    For the moment, let's not even start the discussion about the "plumbe quick" rubber sleeves, vs. the banded couplings. There are issues here, but I digress.

    First, what is that stack you are cutting into? If it is carrying waste from an upper level, then you need a vent for the washing machine. And where is the trap for the washing machine standpipe?

    Now, if your drains are ABS, you will save yourself some hassle by just using ABS for the washer hook up. But we need to answer those questions above.
  3. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    26,253
    Location:
    Cave Creek, Arizona
    connection.

    The answer to your question is easy, because NEITHER way is an approved connection to an indoor stack above ground. Plus you will need a vent, not an air admittance valve, which can be a major undertaking by itself.
  4. stonypaw

    stonypaw New Member

    Messages:
    5
    The ABS stack is the main waste stack in the house. There will be a trap to where the washing machine will be installed. ABS is not so readily available in my area. I dont want any issues with the so called green universal glue. Since the house is 30+ years old, everything was done with ABS and I would like to make the washer drain transition to PVC but keep the stack I need to know what is the appropriate way to do this? This is a basemernt hookup, and all other drains, tub, shower, toilet, are from above from the first floor. The venting is all done from upstairs to the roof and not accessable from the basement. I have just bought this house, and the old washer hookup was done with a 1-1/2" ABS trap connected directly to the stack, and just used a vented grommet thing over the short washer standpipe. There was no other vent. I want to move the washer about 8 feet away from where it is now, but still in the basement, for logistic reasons. For venting, will an AAV be ok?
    So will a 3"" Fernco T fitted over both ends of the stack be the way to go, or can I use the method shown in the sketch? If none of the above, then what is the way to go to getting the washer hooked up proper?
    My apologies for the "cartoon-ish" drawing. It was only intended to show the the area of the T where I am most intreseted right now.
  5. jimbo

    jimbo Plumber

    Messages:
    8,997
    Location:
    San Diego
    Your drawing is fine.

    You don not want to use a rubber fernco Tee. This will be very vulnerable if you ever need to snake out the line from above.

    It is OK to cut in a PVC tee using banded clamps. In this application, no matter what the material, it will need the use of banded clamps to make the insert connection.

    The real issue is the vent. Are you sure there is no vent going up from where the existing washer trap is? Maybe inside the wall?
  6. stonypaw

    stonypaw New Member

    Messages:
    5
    Thanx for the response. The vent does come into the basement, up high along the cieling. But the trouble is they connected the upstairs bathroom sink drain, in the wall behind the sink, to the vent leading to the roof. Basically, the original bath sink drain goes into the vent upstairs, so to cut into the little bit of vent showing in the basement where it connects to the waste stack would be a disaster. The only alternative I see right now is to somehow, run a dedicated vent to the attic, the pick up the vent pipe from there. That is a logistical nightmare in this place, if possible at all.
    Regarding the T into the waste stack for the drain, I was looking at using the Fernco Plumb Qwik 3" to 3", part number 1056-33 on either side of the PVC Tee. They have 2 screw type hose clamps. Is that what you mean by a banded connection? It stated on the lable to be used with sewer and drain only. Thanx again.
  7. kordts

    kordts In the Trades

    Messages:
    551
    Location:
    exurban Chicago
    The green is not universal glue, it is called "transition cement." It is made for joining PVC to ABS. That is the way I would do it. Next choice is 3" non-shear couplings with a 3x2 PVC tee.
  8. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    26,253
    Location:
    Cave Creek, Arizona
    tee

    You cannot cut the stack and then glue a tee into it, so there is no reason to consider transition glues. You need banded couplings labeled for the type of pipe you are using to insert the tee, with its two pipe stubs glued into it. The AAV will only work if the water coming down the stack does not create a positive pressure, and there is no guarantee that that will not happen.
  9. stonypaw

    stonypaw New Member

    Messages:
    5
    So it will be acceptable to use 2, 3" to 3" Fernco Plumb Qwik neoprene I described earlier? This is a picture of it from the Fernco web site. It states on the lable for sewer and drain use only. Keep in mind this waste stack is in the basement.
    There would be no positive pressure in the waste stack that I can determine as far as the venting goes. I may try the AAV, but if its a problem, I think I found a solution to running a dedicated vent thru the wall, and up to the attic to tie into the existing vent. It only took all mothers day afternoon to figure out the vent drama, and will take some long toothpick size limbs to do it, but I might be able to do it.

    Attached Files:

    Last edited: May 11, 2008
  10. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    21,809
    Location:
    New England
    That coupling is ONLY supposed to be used underground...you need the thinner banded couplings (they have a metal band around them for reinforcment and to keep the pipe ends aligned).
  11. MACPLUMB 777

    MACPLUMB 777 TROJAN WORLDWIDE SALES RP

    Messages:
    679
    Location:
    Houston, Texas, United States
    That Coupling Is Outside Foundation Underground Not Inside The Building ! ! ! Get It

    Use A Full Metal Jacket Style Couplings ! !
  12. stonypaw

    stonypaw New Member

    Messages:
    5
    Ok, Ok! Thats the info I was looking for all along. Thanx a bunch, jadnashua. Being a little bit more specific with replys can make life easy.
    To you, MACPLUMB 777, maybe next time a picture or part# of exactly what is needed wont waste my time or yours. NO NEED TO YELL!!. :mad: Just looking for info on what is supposed to be used to make that connection. This guy likes glue, that guy doesnt like glue,, this guy is ok with AAV, that guy says no AAV. Refering to a banded connection doesnt totally narrow it down to a particular part. After sifting thru all the contradictory reply's, and doing my own deeper research, I have the info I was looking for from day 1.


    Quote the wise man:
    "Sarcasm and ignorance is only an indication of one's own insecurity."
    Tolerance and ones desire to learn earns praise and respect.
  13. loafer

    loafer Mechanical Engineer

    Messages:
    49
    Location:
    Maine
    As for venting the washer trap...

    I know code requires it but, almost every older home (25+ years) I've seen here in Maine that has a basement washer hookup does not have a vent for the washer trap. Why? Because up until recently back venting was allowed for almost everything. We only recently adopted the UPC.

    My existing house has a 1.5in washer drain in the basement with a drum trap and no vent. I thought about changing it, but it works so well that I figure I would leave it. I also recently installed one of those new front loaders with the higher flowing pumps; still no problems.

    II know most people don’t like drum traps, and they are no longer code compliant, but I’ve noticed that the one benefit of drum traps is they are virtually impossible to siphon dry.
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