Upstairs toilet flush draws from downtairs bowl

Discussion in 'Plumbing Forum, Professional & DIY Advice, Tips & ' started by tanber, May 3, 2009.

  1. tanber

    tanber New Member

    Messages:
    4
    After new toilet: flush pulls from other bowls

    I just replaced a very old toilet in an upstairs bathroom with a new Kohler w/ Class Six. I've installed 5 other toilets, so I have some experience. I replaced it because it because it was leaking from the wax ring and since it was old (and blue), I just replaced the whole toilet while I was replacing the wax ring.

    New toilet works fine, but after the installation, whenever any toilet in the house is flushed, water is pulled from the bowls of all the other toilets in the house (three toilets in house).

    I have an Odor Hog air filter on the vent on the roof.
    Last edited: May 3, 2009
  2. jimbo

    jimbo Plumber

    Messages:
    8,997
    Location:
    San Diego

    Your problem may well be related to the vent. I have never seen a filter on a plumbing vent.....but if you have one and it is restricting air flow, that would be an issue. Maybe it is clogged.
  3. plumbingskool

    plumbingskool Retired Tradesman

    Messages:
    49
    Location:
    NY
    Why, would you have a filter on the roof?

    and I agree with the above, you have a venting issue....
  4. 99k

    99k Radon Contractor and Water Treatment

    Messages:
    460
    Location:
    Fairfield Co.,Connecticut
    Last year I had a vent problem that resulted in my sink gurgling when the commode was flushed. I never had a vent problem before and we recently took down a large white oak that overhung the house ... why was there a problem?
    I went on the roof and shined my light down the stack ... looking up at me was the largest tree frog I ever saw in my life ... he made a nice nest in the L and he was apparently displaced from the tree removal.
    Took out the shop vac and sucked him and his nest out ... problem fixed.
    BTW, the frog was OK and I released him in the garden.
  5. Terry

    Terry Administrator Staff Member

    Messages:
    14,889
    Location:
    Bothell, Washington
    That's pretty common with some of the new toilets.

    I think more care is needed with some of the faster flushing toilets.
    They drop 1.6 gallons in seconds.

    The old toilets would take 20 seconds to drop two gallons, and then two minutes to slowly waste another three gallons.

    In new construction, I would quit plumbing with a fixture cross for back to back toilets.
    The water will run up the other arm, and force water up in the bowl next door, and when the water drops down, it loses some.
  6. kingsotall

    kingsotall Plunger/TurdPuncher

    Does this occur when only the new one is flushed¿ You say all toilets flushed draw water from all toilets.
  7. loafer

    loafer Mechanical Engineer

    Messages:
    49
    Location:
    Maine
    We have a charcoal filter on our 3in main vent. I think the previous owners installed it because they could smell sewer gas while sitting on the back porch.

    Here is a similar model to what we have.
    http://www.spotfree.net/

    I have seen no indications of the filter inhibitting air flow so I have left it in place.

  8. Redwood

    Redwood Master Plumber

    Messages:
    7,453
    Location:
    Connecticut
    I would try it with the filter removed.
    Just to see what happens...
    If removal fixes the problem I would say it is time for a new one, if odors are objectionable.
  9. tanber

    tanber New Member

    Messages:
    4
    Thanks to all!

    Summarizing all replies to date:

    I will try removing the filter and peering down the pipe for frogs, etc. If there is a problem, I will assume that the old slow-flushing toilets did not have the issue because the leaky wax ring was providing air to the stack and after replacing the ring and toilet, there was no more air supply and thus suction from all toilets.

    Existing filter is less than 12 months old, but if it is causing the problem, I'll leave it off and monitor the odor situation.
  10. tanber

    tanber New Member

    Messages:
    4
    Thanks again to all. I got up on the roof this morning and removed the charcoal filter. The vent pipe was clear all the way down to the first toilet (as far as I could see).

    However, I noticed a lot of moisture (condensation, I assume) in the filter and soaking the charcoal itself, which would explain the blockage. I'm assuming the change of seasons has caused the moisture (cold metal rain cap over filter) and thus the blockage, which I did not notice due to the leaky wax ring on the old toilet. Once I fixed the wax ring... the problem manifested.
  11. Redwood

    Redwood Master Plumber

    Messages:
    7,453
    Location:
    Connecticut
    Moisture is quite normal at that point of the system.
    How is it working without the filter?
  12. tanber

    tanber New Member

    Messages:
    4
    Works great. Flushes do not draw from other bowls, so that was definitely the issue. I'll just see if we get any odor from the vent this year. It's possible there won't be any odor, since the septic was new last year. Now that it is established, maybe it won't smell.
  13. Redwood

    Redwood Master Plumber

    Messages:
    7,453
    Location:
    Connecticut
    It is possible that a new filter if needed will not cause the problem.
    It is also possible to upsize the filter to 4" if needed.
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