Toto flap and water hammer

[Geoffrey Leach the Other]

I cleaned the tank of my Toto CST 854 for the first time in 8 years. Very little debris in the tank and nothing in the feed tube. However, when the cleaning was done, the Toto had an almost imperceptible leak that resulted in periodic water hammer that lasted a few seconds. Re-positioning the flap appears to have resolved the issue.

Questions:
1. Have I diagnosed the problem and solution correctly, or am I kidding myself?
2. For this toilet, is periodic replacing the flap suggested? What about the rest of the tank "hardware"?

 

[Reach4]

1. Have I diagnosed the problem and solution correctly, or am I kidding myself?

I don't think the flapper can affect water hammer.

What do you call water hammer?

 

[Sponsor]

 

[Geoffrey Leach the Other]

Bang-bang-bang ... thunk (I know that this sounds snakry, but that's truly what I hear.)

 

[Reach4]

Bang-bang-bang ... thunk (I know that this sounds snakry, but that's truly what I hear.)

Water hammer would be one bang when a valve shuts off.

If you have odd toilet sounds, I would start with the fill valve.

 

[Flapper]

Probably the flapper was leaking causing the valve to refill causing water hammer.

 

[Geoffrey Leach the Other]

Hmmm .... well, read and learn. If water hammer properly defined is just one bang, what is the multiple banging? I don't think its the fill valve, as that's plastic and the sound definitely sounds metallic.

 

[Flapper]

Not sure but maybe the fill valve is switching on and off rapidly a few times as the water level is only slightly less; thus causing the multiple bangs. This is the only thing I can think of.
If the flapper is old and leaking, then it should be replaced. Flappers are consumable parts that need regular replacements (as well as most other rubber parts).

 

[Geoffrey Leach the Other]

Not sure but maybe the fill valve is switching on and off rapidly a few times as the water level is only slightly less; thus causing the multiple bangs. This is the only thing I can think of.
If the flapper is old and leaking, then it should be replaced. Flappers are consumable parts that need regular replacements (as well as most other rubber parts).

Well, you should know. Thanks for the data.

 

[Flapper]

Well, you should know. Thanks for the data.

I'm just a DIYer like you are; I don't know everything.

 

[Terry]

I would first open the fill valve at the wall all the way. Sometimes those have a loose washer that can vibrate while filling.
Some fill valves are more abrupt than others. I've seen at least three brands used.
Flappers, depending on water quality, may need replacement from time to time. The same with the fill valves.
If the fill tube from the fill valve directed into the overflow tube. If it isn't, the water may have some wave action from water being dropped into the tank from above. Normally the fill valves let water out the bottom for the tank, and from the top, a fill tube that refills the bowl after a flush.

 

[WJcandee]

I don't know what fill valve was used in that Toto, but if it's the Korky 528, then small variations in water level don't cause the valve to open. Remember, the thing is designed so that no water enters the valve when the water reaches the bottom of the float chamber. Only when the water gets higher does it flow through the side holes and into the float chamber. The water in the chamber is enough to hold the valve closed even when it falls somewhat, and it doesn't fall enough to cause the valve to open until it has fallen a good bit down the height of the float chamber. A ballcock or other-design valve will refill when the water drops just a smidge.

AS TO THE ORIGINAL QUESTION:
I think that after 8 years, it's time to replace the flapper. Easy. Inexpensive. DIY job. Korky now makes a universal Toto flapper which you might want to try. That should do it. The stuttering fill valve is probably the result of, as described above, small reductions in water level due to leak past the flapper or siphon from refill hose not being daylighted over the top of the overflow riser. But a 528 shouldn't stutter like that, if that's what's in there.