Toto Ultramax drops water tank level only when water turned on

Discussion in 'Toilet Forum discussions' started by jim0266, Mar 5, 2012.

  1. jim0266

    jim0266 New Member

    Akron, Ohio
    I heard a sizzling sound coming from my 1.2G Ultramax. I took the cap off the TSU25A fill valve to discover water was spritzing out the top. I called Toto and they sent me a new fill valve even though I was out of warranty. Replaced the valve. A few days later the spritzing was back. I called Toto. They had me check to see if the tank level was dropping too. It was. They had me tighten the screws under the flapper and test to see if the water level dropped if the water supply was shut off.

    I ran tests for about four days looking for water dropping from the tank when the water was shut off. Below are the test intervals. Between each test period I turned on the water, flushed the toilet, let the tank refill and shut off the water.

    1. 4 pm to 11 am
    2. 11 am to 2 pm
    3. 2 pm to 11pm
    4. 11pm to 11:30 am
    5. 11:30 am to 4:30 pm
    6. 4:30 pm to 12:30 pm (16 hours)

    Not once in the time above did the water level drop with the water turned off.

    After about two days with the water turned on I discovered the water spritzing again out of the fill valve and the water had dropped as shown in the video at

    The this happens every time. Sometimes it might take a few hours or even longer for the water to start dropping. It does not seem consistent in regard to time.

    I do not have a Watts braided supply line. It's a plastic tube. Why does my water level drop only if the water supply is turned on? I have not yet tried the food color test to see if the water from the tank is making it into the bowl.

    I have the same Toto downstairs and it does not have this issue, which would seem to suggest it's not a water pressure issue.

    Thanks for any suggestions.
  2. Terry

    Terry Administrator Staff Member

    Bothell, Washington
    If I think there is a problem with water leaking from the tank and it's not the flapper, I like to pull the flush valve, sand the inside of the tank, and then reinstall the flush valve.

    I have had a fill valve stick before. If you don't have the TOTO fill valve handy, you can use the Korky MaxPerformance on it. The Korky 528T works too.

    Normally in this situation, it's water leaking from the bowl that is the problem. I see that the fill valve tube is still on the clip keeping the fill tube from siphoning. That looks good.
    Last edited: Mar 6, 2012
  3. jim0266

    jim0266 New Member

    Akron, Ohio
    After showing the Toto tech rep I've been dealing with on this issue the video above he is sending me a new flush valve assembly. Do you have more detailed instructions on how to sand the tank? What do you sand with, what grit, and what exactly am I sanding? I've haven't taken one of these out yet, but it appears the flush valve extends down. I assume it's the wall the plastic contacts?

    I still don't understand why the tank level only drops when the water is turned on. Thanks for your help.
  4. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    New England
    Normally, the casting is fairly smooth. But, it doesn't hurt to smooth out the area with some fine sandpaper in the area where the gasket has to seal. Some 120 or 200 grit, or something inbetween should work. It's not super critical, but can help if there's a casting bump or roughness in that area. Usually takes all of about 15-seconds.
  5. jim0266

    jim0266 New Member

    Akron, Ohio
    The new flush valve was installed on Friday. I did not sand the inside of the toilet before installing the new flush valve. I wanted to see first if the new valve alone would solve the problem. I was afraid if I sanded the tank before trying out the new valve I would not be certain if the sanding or the new valve alone solved the problem. It's been almost five days and my tank level has not dropped yet with the water turned on, nor is my valve spritzing water.

    Thanks for the help and the valuable resource you provide Terry.
  6. Gary Swart

    Gary Swart In the Trades

    Yakima WA
    Good guys win again!
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