Installed Mansfield Flush Valve - tank slowly drains.

Discussion in 'Toilet Forum discussions' started by ne_plumber, Aug 22, 2006.

  1. ne_plumber

    ne_plumber Apprentice Plumber

    Messages:
    6
    Location:
    NH
    Installed a Mansfield Flush Valve, and I filled tank and then shut off supply, as I'm always nervous about leaks. First time I checked it, figured my son had flushed it when I wasn't looking. Fill it again, and make sure he knows not to flush it - find the wafer level down about 1/2" in first hour. If you leave it over night, it's basically empty.

    No water on floor, etc. - so where's it going? After tankfills and ballcock valve shuts off, I hear no "leaking" sound. I'm stumped.

    Thanks,

    Brett
    Last edited: Aug 22, 2006
  2. Mikey

    Mikey Aspiring Old Fart, EE, computer & networking geek

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  3. ne_plumber

    ne_plumber Apprentice Plumber

    Messages:
    6
    Location:
    NH
    Mikey - I'm assuming that is in to the toilet, so assuming that, what do I do to fix it?

    PS - I don't have a cat.

    Dave
  4. Mikey

    Mikey Aspiring Old Fart, EE, computer & networking geek

    Messages:
    2,736
    Location:
    Central Florida
    There's only one place for it to go, and one way to get there. Your flush valve is leaking. Mansfield (http://mansfieldplumbing.com/tank_ts.asp) suggests you check around the edge of the flush valve seal to make sure it's not rough or wavy, and that it's seated in the top groove of the Flush Valve Body. Not sure what parts you've just replaced, but a seal kit is only a couple of bucks. I would add -- check the flush valve seat (body) to make sure it's smooth and not nicked or something. There are a number of DIY sites on the Web that talk about Mansfield repairs -- just Google {Mansfield "flush valve"}.
  5. maddog

    maddog Engineer

    Messages:
    129
    Location:
    near San Jose, CA.
    I have one Mansfield left in our house - and periodically I hear the tank "topping off" from a small leak. I then shut off the water, take a wet paper towel and wipe down the bottom of the flush valve float and the top of the flush valve seal. This seams to work. I figure it's caused by the the chemical disks my wife is always putting in the tank ....
  6. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    22,319
    Location:
    New England
    Those tablets in the tank severely shorten the rubber components life...be prepared to replace them.
  7. ne_plumber

    ne_plumber Apprentice Plumber

    Messages:
    6
    Location:
    NH
    If I put food coloring in, how do I differentiate whether it's leaking at the flush valve seal, or it's the gasket that's sitting between the mansfield valve body to bottom of tank interface? Keep in mind, the Mansfield valve is brand new - not saying a new valve seal couldn't be defective.

    I know it's not leaking at that big thick spud washer (think that's the correct name) that goes between the tank and the recessed hole in the toilet base - as if it was, I'd have water running around the surface of the toilet where the seat is attached.

    Thanks
    Last edited: Aug 22, 2006
  8. Verdeboy

    Verdeboy In the Trades

    Messages:
    2,051
    Yes, It's mostly likely this gasket that's causing you problems. Even new gaskets (and flappers) can be bad.
  9. ne_plumber

    ne_plumber Apprentice Plumber

    Messages:
    6
    Location:
    NH
    Verdeboy - what's you're recommendation. Should I throw some plumbers putty at that interface and re-tighten, or should I go for a new washer? Could the actual bottom surface of the tank be the issue?

    Thanks

    Brett
  10. plumber1

    plumber1 Plumber

    Messages:
    1,423
    Location:
    Florida
    mansfield

    If its like the one in the picture on the other post can only be where the where the upside can and rubber seat meet. replace the rubber seat.

    Mansfield still makes a better flush valve assembly than the one pictured.
  11. Verdeboy

    Verdeboy In the Trades

    Messages:
    2,051
    Just replace the rubber seal (gasket) on the inside of the tank. Bring the old one in to the hardware store and match it up. Buy two, they're cheap.

    I've never heard of using plumber's putty for that purpose.

    It seems to me that if the bottom surface of the tank is the problem that water would be leaking down the tank and on to the floor.
    Last edited: Aug 23, 2006
  12. ne_plumber

    ne_plumber Apprentice Plumber

    Messages:
    6
    Location:
    NH
    Why I thing it's that bottom tank to Mansfield flush valve, is the fact that the tank is bone dry. I would think that if it was that red rubber valve - it would still have a 1/4" of water sitting in it - due to the height of that gasket above the floor of the tank. My theory is that it's draining in to the center of the spud gasket and then just running in to the toilet bowl.

    Anyone buy this theory? Again, the tank is bone dry - and I'm not talking about sitting for a long time and evaporating the last 1/4".

    Brett
  13. Verdeboy

    Verdeboy In the Trades

    Messages:
    2,051
    Your theory is definitely plausible. You can rule out the red rubber gasket as a possibility by filling up the tank and pushing down manually on the plastic tube, in an attempt to make a good seal with the rubber gasket. If the water still goes down, you'll have to take the tank off and try tightening the nut on the underside of the tank. Some of the plumbers here talk about doing some sanding under there as well, in case the surface is rough. You'd of course, have to remove the whole flush valve first.
  14. Mikey

    Mikey Aspiring Old Fart, EE, computer & networking geek

    Messages:
    2,736
    Location:
    Central Florida
    Bench-testing the tank

    Certainly sounds like the tank-to-valve assembly interface is where the leak is. Since you're going to have to take the tank off to fix this, why don't you just take the tank off without disassembling anything, set the tank on a bucket, and fill it (the tank) with water. Then you'll be able to see exactly where the water is coming out. Take pictures.
  15. ne_plumber

    ne_plumber Apprentice Plumber

    Messages:
    6
    Location:
    NH
    Mikey - excellent idea. I figured I'd be pulling the tank off - so like you say, why not see where exactly it's leeaking. It leaks so slowly, I'll probably have to set it up in front of my Lazy Boy, with the Sox game on the tube.

    Brett
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