Washing Machine does not drain correctly… slow drain.

Discussion in 'Plumbing Forum, Professional & DIY Advice' started by Sillycatnip, Apr 16, 2007.

  1. Sillycatnip

    Sillycatnip New Member

    Apr 16, 2007
    Washing Machine does not drain correctly… slow drain.

    Back story which might or might not help: Skip to end of post to see main issue.

    - Recently my girlfriend purchased a house and we discovered there was a drain issue.
    - We installed a garbage disposal unit to help with clogging and when we redid the sink pipes, we discovered a much worse drain issue with our main drain line.
    - The drain pipe runs from the sink to the basement and a pipe runs right next to it (old house 40 years old) the pipe next to the main drain pipe runs to the roof most likely the vent pipe.
    - The main drain connects into a y – tube connection that also connects the vent pipe.
    - We blasted the sink drain and it appears to have fixed the slow drain in the sinks.
    - We got everything working correctly and have not had an issue at all with the sink (4 days now).

    Start of washing Machine Issue:

    - We hooked the washing machine up after having to make a new washing drain pipe, old one was cracked. We used 2’ pipe.
    - When the water hits spin cycle, it begins draining into the pipe and fills up in about 10 seconds and begins overflowing.
    - When I stop the cycle the water drains within about 10 seconds with no standing water at the bottom.
    - I have checked the access point to the sink drain and watched the water quickly and freely drain.
    - I have used pipe cleaning solution in the washing machine pipe several times with no fix.

    The issue seems to be that the water is not draining fast enough, but have no idea what the issue is. The two main drain/vent pips connect at the bottom, but the sinks drains correctly with no issues. Al though the washer appears to drain at the bottom of the vent pipe the two connect. Why would one not drain fast while the other works perfectly… Could I need a larger p trap or pipe? I have included a rough drawing of the configuration to help readers understand the setup. The left pipe extends to the roof and the right pipe extends to the sink.

    Any help would be appreciated.

  2. geniescience

    geniescience Homeowner

    Nov 27, 2005
    humid summers hot, humid winters cold
    If I read this right, you haven't done anything yet to check the drain beyond the washer hookup.

    If I read this right, you cleared up the piece of drain up to the sink as shown in your diagram. That history shows that drain problems (plural) existed already, which adds weight to the hypothesis that there are now problem(s) downstream of what is shown in your diagram.

    An unobstructed vent is also critical.

    Washing machines spew out tons more water than any bathroom sink will ever have to drain.

    FWIW, front loading washing machines use far less water; that doesn't solve your drain problem.

    That's as much as I can comment. Others will help you more.

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  4. Sillycatnip

    Sillycatnip New Member

    Apr 16, 2007
    I appreciate any feed back.

    We, unfortunately, did not check the drain beyond the washer hook up (but we did check the sink drain from top to bottom).

    I guess we got sloppy as we were fixing the other issue for hours (clearing the pipes, wiring, etc). I guess we assumed that because the fixture was only 6 inches above the y joint that connected both pipes that any back age would be seen in both pipes at the access point since they share the same y joint connection.

    I was hoping to avoid removing the washer drain pipe, but it might be something I try tonight.

    There is no standing water when I stop the washer and let it drain (5-10 seconds), so I assumed it was a partial block which I hoped the thick gel drain cleaner would correct (which it didn’t), but I would have to imagine that the pipe they (vent/washer drain and sink drain) are not blocked because the sink drains very well even with a hose pumping in water.

    I thought even a 2’ drain pipe may be too small, but even if I increased the size, I would still encounter a similar issue because the drain pipe would still need to connect to a 2’ access point.

    A friend suggested that there may not be enough suction created.

    Would a seal used to cap off the top of the washer drain and the washer hose help solve this?

    Any advice big or small is welcomed and appreciated.

    Maybe changing the washer drain to the sink drain would help with this leaving a clear vent pipe?
    Last edited: Apr 16, 2007
  5. Gary Swart

    Gary Swart In the Trades

    Sep 1, 2004
    Yakima WA
    My first thought until I read everything completely (something I don't always do) was that you were using 1-1/2" pipe. Then when I saw you were using 2", I thought you might be going into a 1/1/2" drain. After finishing my reading, I am as puzzled as you are. Are you certain the drain never is reduced to 1-1/2" somewhere?
  6. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Sep 2, 2004
    Retired Systems engineer for defense industry.
    New England
    The washing machines stand pipe needs to be high enough (don't remember the specific height but I think it is around 34"), be made out of 2" pipe, and must be vented. Note, you cannot hook a 2" pipe that runs into a smaller pipe, so make sure it is at least 2" from the new stuff you added all the way out.
  7. Sillycatnip

    Sillycatnip New Member

    Apr 16, 2007
    The washer pipe is about 36-38' from the bottom of the washer... it reaches the top of the washer.

    The washer drain is 2' including it's access (2' access hole) into the bottom of the the vent pipe.
    Last edited: Apr 16, 2007
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