Leaking G-Max or Power Gravity Fill Valve.

Discussion in 'Toilet Forum discussions' started by jt3, Jun 13, 2007.

  1. jt3

    jt3 New Member

    Messages:
    3
    Location:
    southeastern MA
    Recently installed a new Ultramax with the G-Max fill valve. Initially the tank filled to the very top of the flush tower / overflow tube and you could hear and see the water running over the top and down to the bowl. Adjusted the fill valve so that the water stops at the line on the fill tube that is about 1/2" below the top. Everything appears fine after the flush. Water stops at correct level and the bowl fill line shuts off. After 5 to 10 minutes, water starts dripping out of the bowl fill line and must also be coming out of the fill valve because the water slowly rises in the tank until it is weeping over the top of the overflow. (Takes between 30 and 60 minutes to reach top of overflow, haven't really timed it)

    Fill valve is not the "Korky" type shown in several posts but is flat on the top and says G-Max. Is this unit serviceable like the Korky valve or do I need to contact the retailer and get a new valve? If it is servicable, a diagram would be nice if available.

    Thanks,

    jt3
  2. Terry

    Terry Administrator Staff Member

    Messages:
    15,130
    Location:
    Bothell, Washington
    [​IMG]


    www.terrylove.com/korky

    Sometimes just cleaning the assembly cap works.
    The instructions for the Korky/Hunter work on this.
    You don't need tools for this.
    If you need a new cap, Lowes sells it for $2.47
    On a new valve though, it's more likely some dirt is the problem.

    [​IMG]

    [​IMG]
    Last edited: Nov 7, 2013
  3. jt3

    jt3 New Member

    Messages:
    3
    Location:
    southeastern MA
    Thanks Terry,

    Tried your suggestion but the inside of the mechanism is a little different from the Korky and I don't want to force (and possibly break it) unless I have a replacement handy)

    Finally got a reply back from Toto (E-Mail problems) and called their Tech Support person. His suggestion before replacing the valve was to check the screen at the bottom of the unit where the supply line connects and he also questioned the water pressure. Since we have very good water pressure here (85 to 100 psi) that could be the problem. May need to install a pressure regulator / reducer on the line to reduce the pressure to something around 50 to 60 psi.

    Will probably pickup one of the "Korky" valves first and try that. (Least expensive to start) If it still bleeds by, will have to install a regulator.

    Will let you know how things work out.

    Jim
  4. Terry

    Terry Administrator Staff Member

    Messages:
    15,130
    Location:
    Bothell, Washington
    Most codes require that anything over 80 psi should have a pressure reducer and an expansion tank.

    If you have the non-Korky style fill valve, then don't try taking it apart.
  5. xmcspc

    xmcspc New Member

    Messages:
    3
    Location:
    Alberta
    gmax fill valve leaking

    I also recently installed a brand-new Toto Ultramax with G-Max fill valve, and have had nothing but problems with the fill valve leaking. Toto tech support has been very responsive, and has sent out multiple replacement fill valves. All have shown the same symptoms... works fine for 1-2 weeks, then starts leaking.

    The symtpoms are exactly as jt3 describes... water fills quickly to the proper level, then shuts off. Over anywhere from 10-30 minutes, the water slowly creeps up the fill tube, then overflows. The interesting thing is that water does not drip from around the top of the valve or the fill tube itself. I spent a bit of time troubleshooting and the water is coming from the base of the tall "tube" that forms the upright part of the fill valve assembly. Having several discarded G-Max valves on hand, I took one apart and it seems that the only way water can come from this part of the fill valve is if one of the two the largest internal rubber seals is slightly out-of-spec (i.e. thin).

    I'm beginning to think there is a manufacturing defect in the fill valves. I could understand how one valve might leak... but I'm currently on my 3rd fill valve in 3 months.

    I definitely want to keep the Ultramax, it's a great toilet. Now I'm researching repacement valves. Anyone know know a Canadian distributor for Korky's? The Home Depots in my area (Western Canada) don't carry them...

    Oh... and if you have a recently-installed Toto with G-Max... you should check to make sure it's not leaking... this is a very silent leak and could easily go unnoticed.
  6. Peanut9199

    Peanut9199 Customer Service Manager Plumbing Wholesale

    Messages:
    875
    Location:
    Ontario, Canada
    They don't have them in the big box stores in Canada they want you to go through plumbing retail or boutiques.

    The only time i have seen the fill valves fail is from the diaphram cap.
    If it continues to run and you replaced the fill valve 3 times you might want to check the Flapper. It may be losing water if the flapper is not sitting properly or even the flush valve may not be smooth and water is escaping from there as well.

    Call Toto and ask them for part # THU013Z which is the flush valve assembly. If they question you tell them the fill valve runs over time and you replaced the fill valve already, they should send you out this part.

    www.terrylove.com/korky
    Last edited by a moderator: Jun 10, 2011
  7. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    22,152
    Location:
    New England
    Buy a water pressure gauge and check out your static water pressure. It could be exceptionally high, and that is what is giving you problems. You may need a pressure reduction valve. Around here, you can buy a gauge for around $10 US at HD. It will screw into a hose bib, either outside or at the washing machine, and other places if you buy adapters. If the pressure is above 80 pounds, you need a prv.
  8. xmcspc

    xmcspc New Member

    Messages:
    3
    Location:
    Alberta
    Thanks for the advice. I'll check the pressure. Even if it is high, I wouldn't expect the more expensive Toto to be affected by it when my substantially-less-expensive (and 15 to 40 year old) other brand-name toilets handle the same pressure just fine.

    Also... I discovered a neighbour (same water pressure) has an Ultramax with the older-style (Korky? - definitely not "GMax") fill valve. It's a couple of years old and has never had a problem with the fill valve.

    With respect to the flush valve, if I turn off the supply water, the water level in the tank doesn't drop, so my interpretation is that the flapper/flush valve isn't leaking.
    Last edited: Jun 24, 2007

  9. That's a bad draw comparison in your statement regarding pressure.

    It's very possible and likely to overpressure old tires on a car and never have a blowout, do the same thing with new tires and a blowout occurs.

    60psi is what all plumbing fixtures/valves/stops along with dishwashers/washing machines are engineered for.

    If you are running well above that in regards to high pressure and discounting logical thinking, put the american standard toilets back in.

    High water pressure if that is your situation can greatly affect the operation of fill valves........korky and fluidmaster. They take a beating when those valves close.


    Dirt in Korky assemblies will cause some really strange occurrences when they stop working. Almost like a teeter-totter fill and they significantly reduce the bowl refill for the next flush. Did one last week, caused solely by fire hydrant draining. I could of cleaned it and reinstalled but I didn't want it to happen twice........2nd time would be my freebie for not following standard procedure.
  10. xmcspc

    xmcspc New Member

    Messages:
    3
    Location:
    Alberta
    Thanks for the info, Rugged. Much appreciated.

    I purchased a pressure gauge and measured 100psi at my outside hose bib. I was quite surprised to see it that high. I've schedule an install of a pressure reducing valve.
  11. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    22,152
    Location:
    New England
    Remember, with the PRV, you MUST also install an expansion tank, or you'll get even higher pressures when the water heater is running...the cold water getting heated will drive the pressure up and cause the T&P valve on the WH to leak.
  12. tnedb

    tnedb New Member

    Messages:
    1
    Location:
    New York
    Terry and everyone else...
    My G-Max would "pulse" when refilling the tank after a flush--at about one second intervals--on / off, etc., until the tank was full, then it would cut-off normally--no leaks. I have 2 UltaMax toilets, 4yrs. old, same problem. I was completely baffled, and had never opened up a G-Max valve. I stumbled on this thread Saturday morning, and since my problem was similar, I thought I'd take the valve apart. Looking at the old valve, the pattern of the tube was imprinted upon the rubber in the cap. I had no point of reference (thought this pattern was normal) until I looked at the new valve at Lowe's--no imprints! I know now that the imprint was causing the leak--but never saw that referenced in the discussion. Needless to say, I replaced both caps, both toilets refill just fine now, and I just wanted y'all to know that this "pulsing" exists, a new cap will fix the problem, and that the rubber in the cap is not imprinted with any type of pattern from the mfg. if you have never seen a "virgin" one.
    Thanks so much...
    tnedb in TN
    Last edited: Jun 25, 2007
  13. Jack D

    Jack D New Member

    Messages:
    1
    Location:
    Boca Raton, FL
    My 2 yr. old one-piece Toto toilet is dripping into the overflow pipe

    How can I stop this from dripping? Water is dripping from the Refill Tube into the overflow pipe.
  14. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    22,152
    Location:
    New England
    Two things come to mind: your house water pressure may exceed the 80# normally considered the max for a home, or the seal in the fill valve may have some debris (maybe a sand or mineral particle) caught in it, and it can't seal, or the seal is worn. They usually last longer than that. If the valve is the one made for them by Korky, the solution is probably a new seal cap, available at Lowes, or any plumbing supply, and some hardware stores for less than $3. It can be changed in a minute or so, once you figure it out (the instructions are on the package). If you're really lucky, you can take the existing one off, wipe away or rinse away some debris, and put it back, and it works...usually doesn't work, but does sometimes and costs nothing. Then, when you do buy a new one, you'll know how to replace it!

    If your water pressure is too high, it gets more complicated, and you need a pressure reduction valve (for the whole house), and an expansion tank. If you already have a PRV and expansion tank, the PRV could be shot, or the expansion tank may need service, or replacing. The toilet fill valves are rated for 'normal' water presssure, and may be the weakest link, and only leaking when the pressure is high. You might want to pick up a water pressure gauge (get one with a tattle tale hand), hook it up somewhere (hose bib, washing machine, drain of the WH or anywhere with adapters) and leave it for a day or so and monitor it and check the tattle tale to see what the pressure is doing.
  15. jerfrank

    jerfrank New Member

    Messages:
    3
    Location:
    norwalk, ct
    jerfrank

    Hi: I have a problem with a GMAX?Korky Quitefill toilet tank fill valve. After seven years of never having a problem, I found that the water level was too high and was flowing into the overflow pipe. I adjusted the fill valve by lowering it and found that the water was filling higher than the water level line on the tank fill valve and, hence, continuing to go over the overflow pipe. Can this be fixed or must I buy a new valve?
    Jerfrank
  16. Terry

    Terry Administrator Staff Member

    Messages:
    15,130
    Location:
    Bothell, Washington
    I would pop in a new assembly cap for $2.50
    It's the easiest fix, takes about 30 seconds without tools.

    [​IMG]
  17. jerfrank

    jerfrank New Member

    Messages:
    3
    Location:
    norwalk, ct
    Terry:
    I have a G-Max valve. They look alike but will the korky replacement cap fit the G-Max?
    Thanks
    Jerfrank
  18. Terry

    Terry Administrator Staff Member

    Messages:
    15,130
    Location:
    Bothell, Washington
    Korky makes the fill valve
    There are three brands used, but they all look different. If it looks like a Korky, then it is a Korky.
    $2.50 part fixes it in less then a minute without tools.
  19. jerfrank

    jerfrank New Member

    Messages:
    3
    Location:
    norwalk, ct
    Hi again:
    This jerfrank. I replaced the valve cap and the water still came up and over the fill valve and the overflow pipe. I then examined the new Korky valve I had purchased (that's how I got the valve replacement cap since Home Depot didn't have just the valve replacement cap and there is no Lowe's near me) and noticed that the arms one squeezes to release the float were kind of squishy. I took the new toilet tank fill valve, pulled the top off and saw the the float arms were much more substantial so I put it into the old tank fill unit and, voila, no more running over. Now how long this lasts is anyone guess but if it works, I suggest some of you folks give it a try.
    GOOD LUCK!
  20. notadiy

    notadiy New Member

    Messages:
    1
    Location:
    Colorado
    Toto G-Max - Water start/stop during fill

    I have 3 Toto toilets in the house. All installed at the same time about 6 years ago. Recently two of them started to have the same problem. When refilling the tank after a flush the water runs 1-2 seconds and then stops 1-2 seconds. It keeps doing this until the tank is full. No other problems with the toilet otherwise and the 3rd Toto does not have this problem.

    Thanks!
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