(206) 949-5683, Top Rated Plumber, Seattle
Results 1 to 12 of 12

Thread: AC condensate into DWV wye?

  1. #1
    Engineer chassis's Avatar
    Join Date
    Sep 2005
    Location
    SE Pennsylvania
    Posts
    339

    Default AC condensate into DWV wye?

    Hello all,

    I searched this site on this question, and I think (hope) what I want to do is OK.

    Presently my ac condensate line is plumbed via 1/2" PVC to a vertical, open (to the air) drain pipe in the basement concrete floor. There is an "air gap" and the condensate line is not solidly connected to the floor drain pipe. The vertical floor drain pipe is presently open to the air, and is not sealed.

    I want to install a new utility sink in the basement, and plumb the sink drain to the pipe which is used by the ac condensate. I propose to use a DWV wye, with the vertical (straight) leg for the utility sink drain, and the wye leg for the ac condensate. The 1/2" PVC condensate line would be run loosely into the wye, therefore maintaining the air gap with no solid connection.

    Is this OK? If not, how would I plumb the two drains properly, utilizing a shared drain pipe in the floor? Thanks.

  2. #2
    Plumber jimbo's Avatar
    Join Date
    Aug 2004
    Location
    San Diego
    Posts
    9,001

    Default

    If I understand your description, you would send the condensate in behind the sink trap. That won't do, because at a minimum you would have an open sewer connection, and possilby would actually draw sewer gas back into the air conditioner. You need to have the air gap somewhere, but you also need to be going into a trap.

  3. #3

    Default

    My condensate drain just runs into my utility sink just like you would run a washer drain hose.

  4. #4
    Consultant cwhyu2's Avatar
    Join Date
    Aug 2007
    Location
    Cincinnati OH
    Posts
    1,330

    Default

    Quote Originally Posted by mrmedic View Post
    My condensate drain just runs into my utility sink just like you would run a washer drain hose.
    That is okay as long as it does penetrate the flood level rim of the fixture it is wasting into.
    Also called a safe waste.

  5. #5
    In the Trades Jerome2877's Avatar
    Join Date
    Aug 2009
    Location
    BC
    Posts
    384

    Default

    Are you sure this drain runs to the sewer? It could be going into the storm drains. If it is sewer then it would have a trap under the slab. Your proposal would not meet any codes.

  6. #6
    Moderator & Master Plumber hj's Avatar
    Join Date
    Aug 2004
    Location
    Cave Creek, Arizona
    Posts
    25,605

    Default

    If that "riser" has a trap under the floor, your proposal seems to be okay, assuming we actually understand what you intend to do.
    Licensed residential and commercial plumber

  7. #7
    Engineer chassis's Avatar
    Join Date
    Sep 2005
    Location
    SE Pennsylvania
    Posts
    339

    Default

    Guys, thanks for the input. I'm pretty sure it has a trap in the floor. I have other floor drains in the basement, and periodically I need to add water to them to replenish the water that has evaporated from them. Is there a way I can verify there is a trap connected to the riser?

    I plan to install a trap on the utility sink. The ac condensate line would flow into the riser by means of the wye. From the condensate line perspective, nothing changes. It has a trap, if one exists in the slab, which I think it does. Therefore the utility sink would have two traps in series - the sink trap and the trap in the slab.

  8. #8
    In the Trades Jerome2877's Avatar
    Join Date
    Aug 2009
    Location
    BC
    Posts
    384

    Default

    I plan to install a trap on the utility sink. The ac condensate line would flow into the riser by means of the wye. From the condensate line perspective, nothing changes. It has a trap, if one exists in the slab, which I think it does. Therefore the utility sink would have two traps in series - the sink trap and the trap in the slab.
    Nope, you can't have traps in series. Floor drains are there for a reason and it probably isn't vented. If you really wanted to do this though I would suggest jackhammering the slab and removing the trap. Then connect to the drain bring it up and then vent it. The condensate drain would probably be too low to use the sink drain so maybe use a pump and plumb it like a dishwasher with an air gap or find another place to drain it.

  9. #9
    Moderator & Master Plumber hj's Avatar
    Join Date
    Aug 2004
    Location
    Cave Creek, Arizona
    Posts
    25,605

    Default

    Actually, you can have as many traps "in a series" as you want to, as long as EACH one has a vent, which would be the case here with an open riser for the A/C condensate.
    Licensed residential and commercial plumber

  10. #10
    DIY Senior Member BobL43's Avatar
    Join Date
    Mar 2011
    Location
    Long Island, NY
    Posts
    1,768

    Default

    Quote Originally Posted by hj View Post
    Actually, you can have as many traps "in a series" as you want to, as long as EACH one has a vent, which would be the case here with an open riser for the A/C condensate.
    Is it against code or good paractice to have an air handler in the center of an attic which has a ptrap at its condensate outlet to drain into a 3 inch main stack/vent in the attic? The nearest end (gable) wall is 30 feet away, but the stack is about 12 feet away from the air handler?
    I am definitely not a pro plumber, but I am a pro crastinator

  11. #11
    DIY Senior Member bluebinky's Avatar
    Join Date
    Aug 2011
    Location
    Santa Clara, CA
    Posts
    354

    Default

    My understanding (of the UPC that is) is that you cannot run a drain into a vent -- even a condensate drain. That said, apparently, it is common practice in some areas to tie into an attic vent...

    Between the AC drain and sewer, there needs to be an air gap (or possibly air break). The gap also acts as a vent allowing for the second (sewer-side) trap as well. Before the gap is considered to not be plumbing, but rather part of the AC -- and the installation is governed by the AC equipment instructions and local "mechanical" code (someone please correct me if I'm wrong). After the gap is, of course, "plumbing". There must be some way to keep the sewer-side trap filled when the AC is not in use. That is hard to do in an attic...

    I vote for ending the existing drain above the laundry tub rim.
    Last edited by bluebinky; 09-08-2011 at 10:19 AM.

  12. #12
    DIY Senior Member BobL43's Avatar
    Join Date
    Mar 2011
    Location
    Long Island, NY
    Posts
    1,768

    Default

    Quote Originally Posted by bluebinky View Post
    My understanding (of the UPC that is) is that you cannot run a drain into a vent -- even a condensate drain. That said, apparently, it is common practice in some areas to tie into an attic vent...

    Between the AC drain and sewer, there needs to be an air gap (or possibly air break). The gap also acts as a vent allowing for the second (sewer-side) trap as well. Before the gap is considered to not be plumbing, but rather part of the AC -- and the installation is governed by the AC equipment instructions and local "mechanical" code (someone please correct me if I'm wrong). After the gap is, of course, "plumbing". There must be some way to keep the sewer-side trap filled when the AC is not in use. That is hard to do in an attic...

    I vote for ending the existing drain above the laundry tub rim.
    When the AC installer put my system in in 1987, he tied the condensate into my vent line, and i did not know it. all these years, we never smelled anything in the house. he did not install any type of trap at all. I recently went up ther and saw this, and I at least put up a trap there (made up of 4 45 degree elbows and 2 unions all PVC). I guess there is enough draft in the stack and/or the condensate port is on the positive pressure side of the blower to not suck in any foul smells and blow them into the house. I'm going to re-do it anyhow and run the line from the air handler to the end wall to outside the house one day. We don't have city sewage systems here; all cesspools. I guess the house trap is working well . What a hack job he did on that, but the rest of the system is good. Still working (well) after 24 years. The trap did not freeze up and crack last winter, so I guess it dried out after the cooling season and before really getting too cold.
    I am definitely not a pro plumber, but I am a pro crastinator

Similar Threads

  1. Condensate Backflow
    By vaman in forum HVAC Heating & Cooling
    Replies: 1
    Last Post: 06-06-2010, 06:06 PM
  2. Condensate pump
    By Ian Gills in forum HVAC Heating & Cooling
    Replies: 3
    Last Post: 09-03-2009, 04:37 AM
  3. Condensate neutralization, or not?
    By jadnashua in forum Plumbing Forum, Professional & DIY Advice, Tips & Tricks
    Replies: 3
    Last Post: 10-19-2006, 05:21 PM
  4. Recirculating ac condensate?
    By prashster in forum Plumbing Forum, Professional & DIY Advice, Tips & Tricks
    Replies: 7
    Last Post: 09-18-2006, 09:37 PM
  5. Condensate draining
    By rharrington in forum Plumbing Forum, Professional & DIY Advice, Tips & Tricks
    Replies: 15
    Last Post: 01-31-2006, 04:46 PM

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •