Toto Fill Valve Makes Noise As It Finishes Filling

[DMY]

Model ST743S

When the toilet is almost done filling, it starts "squirting" water to complete the fill.
Each squirt is accompanied by a kind of plunger noise. It takes about 4 or 5 "squirts"
to completely finish the fill up.

Prior to this issue, the toilet was making air hammer noise. I installed an arrestor,
and the air hammer noise went away and has been replaced by this strange behavior
and noise !

Thanks for any ideas !

 

[Terry]

What is your water pressure?

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

 

[Sponsor]

 

[Jadnashua]

Two things, depending on whether you have the valve made by Korky for Toto. Assuming you do, a couple of things:
- take the seal assembly out and check it. When new, the seal is quite flexible and will be a nice, smooth dome. When it starts to wear out, it will have an impression of the grid in the seal retainer on it. Eventually, it will crack, but in the interium, it can cause that symptom.
- when you check the seal, look at the float carefully and make sure the little hole is clear.

You don't need any tools to take that valve apart, and you can buy the replacement seal in any plumbing supply, on-line, and at least one of the big box stores...it's $3-4 or so, lots less than replacing the whole valve. Depending on your water pressure, that seal may last nearly forever, or only a few. IF your water pressure is really high, you might consider addressing that (often a symptom of water hammer...higher pressure, the water travels faster, so when it stops, it has more energy to hammer).

 

[WorthFlorida]

As the water slows up the fill valve starts to close, the water pressure increases slightly and that opens the fill valve a little more and it cycles a few times. Having to add a arrestor your water pressure may be too high. For now, close the water valve for a slow fill of the tank. I like to open them before the water rushing through the valve starts to makes too much noise. It might help. If the valve makes more noise as you close it, as Terry is suggesting, the water pressure needs to be checked.

 

[DMY]

What is your water pressure?

No idea what the exact pressure is, but I have the water valve which feeds the toilet opened ALL the way up.

I have two other Toto toilets - same model and they work fine - just completely shut off as they should when
the reservoir is filled.

thanks ! I'll try backing off the water pressure and test.

 

[DMY]

As the water slows up the fill valve starts to close, the water pressure increases slightly and that opens the fill valve a little more and it cycles a few times. Having to add a arrestor your water pressure may be too high. For now, close the water valve for a slow fill of the tank. I like to open them before the water rushing through the valve starts to makes too much noise. It might help. If the valve makes more noise as you close it, as Terry is suggesting, the water pressure needs to be checked.

Ok, thanks. I'll give this a try first !

 

[DMY]

What is your water pressure?

Turning down the pressure was the quick fix. Takes a long long time to fill though. Something else must be starting to fail ?

 

[Jadnashua]

Check the two things I suggested.

TO check your water pressure, pick up a water pressure gauge at a plumbing supply store or one of the big box stores...screw it onto say the washing machine supply, or an outdoor hose bib, or (careful, it will get hot!) the drain valve of the water heater. You can also attach it other places if you buy adapters. Get one with the second, tattle tale hand and leave it attached for say 24-hours to check the peak pressure, too.

 

[WJcandee]

I'm assuming that you have a variation of the Korky 528 in there. If you have a different design of valve than the one in the video, ignore this post. (A different cap color or it saying TOTO on it don't change the fact that it's a 528, if your valve looks like the one in the video.)

When you get surging and squirting from that valve during fillup, it's because there is a tear in the rubber of the seal that Jim describes above. Just go pay $3 for the R528 replacement cap/seal, replace it, and you should be fine. (After checking to make sure I'm right, of course.)

(Reason: When the seal rips, which is rare, water cascades into the float chamber during fill. Normally, the float chamber has no water in it until the valve is 2 seconds from closing off. When the water level reaches the shutoff level, it all rushes into the float chamber from the waterline hole at once, and definitively-closes the valve. However, when water goes past the seal and squirts up into the cover cap, it falls back into the float chamber, eventually putting enough water in there to start to lift the float, even though it is also dripping out the hole in the bottom. Hence, surging.)

Obviously, if you post a video, we can diagnose more-correctly what you are referring to, but that's usually it.

You can check it out first. Maintaining the valve and replacing the seal are covered in this video, which applies regardless of cap color:

 

[WorthFlorida]

Turning down the pressure was the quick fix. Takes a long long time to fill though. Something else must be starting to fail ?

FYI. Closing the valve as I suggested only lowers the pressure when water is flowing. Once water has stopped flowing the pressure is the same on both sides of the valve but now the hammer effect is much lower now but it’s not a fix. You can open the valve until the problem shows itself to get a faster fill. I would get a entire new fill assembly for the tank and then work on your pressure issue. If it is high it beats up all other fixtures particularly the dishwasher and the washing machine.