Toto does not shut off

Of the three Toto toilets we installed in our house a couple of years ago, one is now taking a very long time to shut off.

The model is the MS874114S (G) with the THU175S refill valve (a Type A valve).

Even adjusting the valve all the way to the minus direction doesn't help:
The water level rises above the overflow pipe and continues flowing for quite a while after that.. eventually it does shut off, and stays shut off until the next flush.

The Toto tech support person says I need to replace the valve.. is there anything I can do to fix it short of that? And if I do need to replace it, is there a better source for replacement parts than Toto itself?

Toto has a couple of different valves. The one you have is not repairable, if I have it right. The other one (made for them by Korky) can be repaired in about a minute with a $3 part. A generic replacement valve may work, but it may not give you the best performance and proper refill with minimum waste. The ones made for Toto are calibrated to full the bowl and the tank at the same time to minimize dumping excess water down the drain, or not refilling the bowl when the tank is full. So, it's probably best to replace it with one made for Toto.

If you are on a well, you may have some dirt in the water (sand, etc.?) and that can cause the seals to fail by making it impossible for them to close completely. This can also happen on a public water system or even if you do some work on your pipes if the flow is disrupted, or the city flushes the pipes. This will dislodge crud, and can mess with valves.

Thanks.. So if I have to replace it anyway, would it make sense to replace it with the other one that CAN be repaired in the future? Or are they not interchangeable?

Ilmar said:

Thanks.. So if I have to replace it anyway, would it make sense to replace it with the other one that CAN be repaired in the future? Or are they not interchangeable?

Click to expand...

They appear to be interchangeable. I had an issue with the porcelain of one of the EcoDrake tanks I purchased (had a twist to it that resulted in cover wobble), so I swapped it out with another tank that was apparently older and had the Type A valve. The other three I had were all Type B's and after some debate in the store we removed the Type A from the replacement tank and installed the Type B that was in the defective tank. The toilet is operating properly. The Type B's in mine have a raised "528" molded onto them.

The proper Korky replacement is 528T (T for Toto). I've not looked for them at Lowes, but they do carry the flapper valves. A local plumbing supply store may have one. I think the things have a 5-year warranty, so if the toilet isn't older than that, Toto may send you a new one. It might only be one-year, but it wouldn't hurt to call them anyway. the difference between the 'generic' version and the T version is a different sized restrictor to get the proper balance between the water going to the overflow (for the bowl) and the tank.