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Thread: toilet bowl leaks to empty in 30 min, starting at normal level Updated with latest!

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    DIY Junior Member etbrown4's Avatar
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    Default toilet bowl leaks to empty in 30 min, starting at normal level Updated with latest!

    I posted a similar thread a few weeks ago, but it got off into a discussion about good and not-so-good toilets, so I thought I'd start a new one to save folks from reading all that history.

    Here goes:
    Are there any other possible causes of a bowl leaking down to bone dry in 30 minutes, other than a clogged vent, or a possible leak in the internal trap itself?

    Zero moisture shows up in the ceiling below.

    Tips appreciated.

    It's a $6-800 Black Amer Std "Savona" toilet.

    .....................And the Update:

    Initially we thought we had a leak out of the bottom through a hairline crack................ but maybe not! BTW,

    We tried the very clever idea of inserting the clear tubing through the trapway, and no difference.
    The vent through the roof is totally clear.

    So we pulled it out and set it up high off the ground so we could refill the bowl and observe.

    What we found, blows our mind! With 16 ounces of water in the bowl there is no leak. With 24 ounces in the bowl it leaks out of the main toilet outlet with a pretty good drip drip drip. A normal bowl level for this unit is probably around 40 ounces or so, and 2-3" higher water level, than the level with just 16 ounces of water in the bowl.

    I'm 99% sure, with just 24 ounces of water in the bowl, it's not leaking through the main trapway. There is a 3/4" factory hole extending toward the front of the toilet, located maybe 2" above the bottom of the round outlet at the bottom of the bowl. Looking at the toilet turned upside down, you can see that there is a small passageway coming from that front side and connecting underneath into the main bottom outlet.

    Not sure the purpose of that small passageway, but I'm pretty sure that the leak is taking that route. If so, it's hard to understand, but there is a definite leak, even at very low water levels in the bowl. It's hard to imagine that it was this way when it left the factory but I guess it's possible.

    Ideas still appreciated!

    PS. The bone dry trapway reported earlier may have been due to some unusually high winds, encountered earlier, though now not a factor. Once the water level got way low, it was probably easy for the howling wind to pull air inside the house through the trapway up through the vent, and dry it out.
    Last edited by etbrown4; 11-03-2012 at 02:39 PM.

  2. #2
    Retired Defense Industry Engineer jadnashua's Avatar
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    A toilet will flush without a vent. A clogged vent will NOT siphon a toilet dry. Air movement in a vent can rock the water in the toilet, but would not siphon it dry. The rocking could cause some to slosh over the outlet weir, but it would take some really high winds to affect the level much. That hole may have been for hot gasses to escape during the firing in the kiln...it likely should have been plugged prior to leaving the factory, and it may be that it was not done properly and fell out sometime and you noticed the level drop.

    Replace the toilet, or if you're feeling lucky, try plugging that hole. But, if you saw a hairline crack, stop wasting your time and replace the bowl, or better yet, the whole thing.
    Jim DeBruycker
    Important note - I'm not a pro
    Retired Defense Industry Engineer; Schluter 2.5-day Workshop Completed 2013, 2014

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    DIY Junior Member etbrown4's Avatar
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    What seemed like a faint hairline crack was in the bottom of the trapway, but upon closer examination, I think it's something in the original china that's ok. That portion of the trapway is dry when the leak is active.

    With regard to that 3/4" hole Ii looks like it's an important part of the design. There seems to be a definite sealed channel or port in the underside of the bowl that appears to be a route for that hole, possibly to feed out to the bottom of the toilet. I have no idea what the purpose might be, but I bet we can figure this one out

    I suppose I could drain the bowl and put some duct seal in the 3/4" hole for a test!

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    Retired Defense Industry Engineer jadnashua's Avatar
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    If that hole is facing the bowl's outlet, it should be there as it's the outlet that starts the siphon effect when you flush the toilet.
    Jim DeBruycker
    Important note - I'm not a pro
    Retired Defense Industry Engineer; Schluter 2.5-day Workshop Completed 2013, 2014

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    DIY Junior Member etbrown4's Avatar
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    Quote Originally Posted by jadnashua View Post
    If that hole is facing the bowl's outlet, it should be there as it's the outlet that starts the siphon effect when you flush the toilet.
    We have two of these Amer Std one piece 'Savona' toilets in the same house.

    Interestingly, one has the 3/4" hole as described earlier and the other does not!

    It is clear that Amer Standard has different internal porting , even on toilets that look the same outside.

    I'm sure that jadnashua knows his stuff, however it appears that there must be several ways to design a toilet, and I guess they both work, or either they used to.

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    Retired Defense Industry Engineer jadnashua's Avatar
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    There are basically two types of toilets over the years that have been commonly sold in the USA - washdown and siphon jet (my terms - not to be confused with bowl wash technique). The older ones with washdown technology generally required lots of water to be dumped to generate enough pressure to create the siphon effect that eventually emptied the bowl. The newer ones generally use a jet of water, pointed at the outlet, to almost instantly create the siphoning effect. This can be done with MUCH less water, but the fluid dynamics are much more critical - design is as important as quality of construction (AS qa is sometimes lacking from reports here). There are several ways to create the required jet velocity and pressure: a taller tank, pressure assist, or more water (flushometer valves which require large supply lines often found in commercial buildings). When the water use restrictions started to come into play, those that had a decent washdown tried to create the same effect with less water and it was often a dismal failure. Most eventually changed their designs. Not all have kept up their QA/QC, and what may be a decent design can have a spotty performance in real life. To create a siphon jet requires more well designed and contructed internal passageways in the toilet where there are more chances of defects since they are hidden from view.

    Regardless of all that, if your toilet leaks internally, replace it, preferably with one with a better design AND construction quality.
    Jim DeBruycker
    Important note - I'm not a pro
    Retired Defense Industry Engineer; Schluter 2.5-day Workshop Completed 2013, 2014

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