How to diagnose Ultramax flushing problem?

Discussion in 'Toilet Forum discussions' started by jch, Dec 14, 2006.

  1. jch

    jch Member

    Installed a Toto Ultramax in our ground floor bathroom last year. Works flawlessly. Never blocks.

    Was having problems with the old (medium-flow) 9L/flush Crane toilet upstairs (frequent blockages). Snaked the line. Didn't make any difference. This toilet has always had flushing issues.

    Finally bought a second Ultramax and installed it upstairs, replacing the old Crane.

    This upstairs Ultramax now blocks after every BM. Liquid flushing--no problem. Solid flushing -- makes a gurgling sound, doesn't flush completely, then doesn't flush at all on the next attempt. Needs a plunger to unplug it. Blocks on next BM.

    The snake is coming up clear.

    1) How do I diagnose what the problem is?

    2) Could it be that there is no (or reverse) slope on the toilet's drain pipe (looks approx 8 feet from stack)? If so, how would I diagnose this without ripping down the ceiling below the toilet? (I'm thinking that the lower flow Ultramax would probably make such a problem worse).

    3) Is it likely to be an obstruction in the drain pipe that a snake won't "find" or clear?

  2. Terry

    Terry Administrator Staff Member

    Bothell, Washington
    Two toilets plug on the same line?
    Sounds like the line.
    I would pull the toilet up and get someone in with a large snake for the waste line, the kind for main lines.

    You can then test the toilet on blocks outside and make sure it's not the trapway of the bowl just to be sure.

    When we set toilets, we always set the wax on the flange, and then drop the toilet onto the wax.
    A wax ring can fall off and drop over the drain opening otherwise.
  3. jch

    jch Member

    That's what I thought too.

    Okay thanks--my snake is just a dinky residential one.

    How would you determine whether the line is not sloped (or vented) properly without ripping open the ceilings below? Like I said, this has been a chronic problem, although more prevalent recently (which to me would suggest a plug, and possibly bad line installation too).

    The old (medium-flow) toilet blocked a couple of times per month. The (low-flow) Ultramax plugs on *every* BM. It's as if there's a hump in the drain line that the low-flow can't make it over. But I'm just guessing.

    Would you use a camera??

    This happened starting on the *first* day of the new Ultramax. Oh man, I'd like to hope that it wasn't pre-plugged from the factory...:)

    That's what I did. Even used a reinforced wax ring with a plastic horn.

    Would a camera be overkill?

    Last edited: Dec 14, 2006
  4. Terry

    Terry Administrator Staff Member

    Bothell, Washington
    Well, I've never heard of a pre-plugged toilet, so I would think it's the line.

    Roto Rooter
  5. markts30

    markts30 Commercial Plumber

    Phoenix, AZ
    A camera certainly would not be my first choice here...
    When you remove the WC you should be able to see into the closet bend...
    If there is any liquid there, there is back-grade (or a clog)...
    The pipe should be fairly clean (no obvious waste) and empty of free liquids...
    I would then pour a bucket of water into the pipe and see what happens...
    If the water does not flow down the pipe as fast as you can pour it (should NOT overflow) , you have a problem that may require a plumber...
    Last edited: Dec 14, 2006
  6. jch

    jch Member

    How would I distinguish between:
    - a properly sloped/vented line that is plugged (and therefore works well immediately after being roto-rooted)? and
    - a line that is not sloped/vented properly and will therefore continue to be on the verge of plugging? (i.e. will need repeat calls)

    Is there a way to tell on the first call?

  7. jch

    jch Member

    I did this before installing the Ultramax. No liquid. Pipe clean. At the time I thought for sure that this meant the old toilet was the culprit.
    Again, when installing the Ultramax, I first poured a gallon of water into the open pipe from a jug, and it disappeared as quickly as I could pour it. Perhaps I needed more than 1 gallon of water? Or I needed a bucket that I could pour more quickly? (although any faster and it would probably spill all over the floor).

    One thing that might be relevant is that a vent pipe from this bathroom comes out into the side attic *under* the floor (i.e. the vent comes along between the floor joists and then up and through the roof). Isn't a vent supposed to be *above* the highest water line in any fixture?

    There's a sink and tub in that bathroom too. The stack is right behind the sink, which is between the tub and the toilet. The tub drains very quickly.

  8. jch

    jch Member

    Another thought.

    Maybe they used a 90-degree bend in the waste line? When I looked in the toilet bend I saw that it was heading off parallel to the floor joists, but the stack is about 5 feet (4 joist bays) over.

    The wiring in this upstairs bathroom was done by a DIY--not sure whether the plumbing was too...

  9. TPA

    TPA Member

    1 gallon isn't much water when you think about it -- the flush alone is 1.6. If you've got a 5 gallon bucket, try mostly filling it with water and dumping it down the toilet. It should be able to take the whole 5 gallons without a problem.
  10. jch

    jch Member

    Just tried it with a 10-gallon bucket. No problems...

    Except, afterwards the bathtub drain started making gurgling noises.

    Which, to me, suggests a venting problem.

    Maybe it is linked to the vent that comes out from within the joist bay.... Perhaps the vent connection is too low, and is plugging up with *ahem*.

    Another thing that makes me suspicious of the venting is that the vent pipe comes out into the side attic via the joist bay (a 6+ foot horizontal run), runs up the 3 foot pony wall, about 20 feet along the top of the pony wall, then disappears up between the bedroom ceiling and the roof sheathing, where it finally goes through the roof. It's as if they cut the roof vent hole 6 feet from the *front* of the house, rather than 6 feet from the *back* of the house and decided to run 20 feet of tubing to connect it up anyway.

    Would bad venting explain this behaviour?

  11. Cass

    Cass Plumber

    Sounds like bad venting.

    Is this an older home with cast iron and galvanized DWV?

    Do you have trees overhanging where the vent exits the roof?

    If you can get on the roof with a flashlight you can look into the vent for any build up of debris in the vent from outside sources. I have seen all kind of stuff like leaves, branches, dead animals, ect.
    Last edited: Dec 15, 2006
  12. jch

    jch Member

    Cast iron only in the basement. The rest of the house has been switched over to ABS. The second story (actually 1/2 story) where the problematic toilet is was converted from attic space in 1992 so that plumbing is all comparatively new.

    In the four years that we've lived here, its flushing has always been so-so (see my first post), but now with this new low-flow Ultramax, it's horrible. Perhaps it's because the Ultramax shoots water into the drain a lot faster than the old siphon-style toilet?

    No trees that tall on the property.

    Oh my. The vent immediately takes a 45-degree bend and follows along under the roof surface so I won't be able to see very far (see post #10 for gory details on the 40 foot circuitous path that the vent takes).


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