TOTO toilet internals 'popping up'

[ginoalbert]

I have three TOTO toilets in our home, which is about 15 years old. One of them (and only this one) has had a problem where the entire fill valve assembly "pops up" with such force that it knocks off the porcelain cover. Water starts spraying everywhere and there is a big mess to clean up. This happened this week. The only other time it happened was 4-5 years ago.

Luckily, we were home both times to prevent the mess from turning into a flood. Neither time was the toilet in the process of being flushed nor filling. No other water was running in the house when it happened either time. The event several years ago happened in the middle of the night, when we were sleeping.

The fill valve assembly locks down with a twist. What could be making it 'untwist'?

 

[Reach4]

I would get a pressure gauge with a "lazy hand" that remembers the peak reading. These are available with a garden hose thread. If your pressure goes above 80, you will want to look at getting/replacing a pressure regulating valve. The gauges are cheap.

In any case, I would replace the fill valve.
Korky 528T Replacement TOTO Toilet Fill Valve - Fits G-Max and Power Gravity Toilets -Easy to Install -Made in USA

 

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[TheUniversalDave1]

If the toilet is that old, then it most likely originally had Coast parts. I don't think Toto started using Korky valves until 2004 or so, but I could be wrong. At any rate, yes, I would put in a new Korky valve.

 

[Jadnashua]

Depending on the valve you have, it may simply be that it needs a slight turn to put it into the locked position! The Korky also comes with a locking clip. I've not had an issue with leaving that out, but it does mean you must be careful if you try to remove the seal, since turning that out might also unlock the tower, which could then move on its own. FWIW, I have one Toto, bought in about 2000 that has the Korky valve, so they did use them before 2004. The other valve they use is flat on top with a large plastic screw. That screw is the height adjuster on that valve.

 

[Terry]

The fill valve is missing the tab that prevents the fill valve from moving.

There is a white tab that slides in there to lock it.
www.terrylove.com/korky

Korky 528T Replacement TOTO Toilet Fill Valve - Fits G-Max and Power Gravity Toilets -Easy to Install -Made in USA

 

[WJcandee]

Water pressure should keep it from popping up. That is, if you have set it to the right height and then twisted it fully into the locking position, that twist raises the valve a smidge into a locked position, and when you then turn on the water, the pressure should hold it in place and prevent it from moving out of the locked position. If it isn't fully-locked into place, when you turn on the water, it will pop up then or eventually. As Terry points out, you can secure it even further by inserting the locking key, but you won't be able to do that until it is properly locked in place. Just get a new 528MP, install it correctly, and then insert the tab if you're concerned about it. Again, the key is fully twisting it into place when you have it at the height you want. (If the valve can't turn freely because, say, it's twisting into the wall of the tank, then loosen the nut under the tank and rotate it so it can twist without being obstructed.)

You can verify that it's in the locked position because the line molded into the plastic will line up with the pegs, as illustrated above.