Water disappears to below the bowl inlet and stop.

It is a problem with the water inlet valve

https://www.plumbersforums.net/threads/how-to-stop-saniflo-toilet-water-running-into-toilet-bowl.106308/

More here.

https://www.google.com/search?q=Saniflow+Sanistar+wall+hung+toilet+won%27t+stop+filling+bowl+with+water


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Hey, One thing is that maybe there might be some loose plastic shavings in the fill line. From the Factory? or maybe was inside the water line going to the toilet when you connected the line to toilet. Shut off the water and get some towels and something to catch the water and disconnect it from the toilet and use bowl or what ever to catch the water and slowly turn it on and see if anything comes out. Maybe if it is in the line inside the toilet it might fall out by lightly tapping on the fill line inside the toilet to help it fall out. Just a thought when you said it "Sings" that sounds like trash inside the line going to the filler tube and bowl, hey try it who knows it might work. Okay

Troubleshoot Your Toilet Without a Plumber

www.popularmechanics.com/home/how-to/a4117/4303948/

Overflowing, constantly running and sweating toilets can test a home owner's sanity. ... take for granted--until we can't take a shower or make the toilet flush properly. ... If none of the above does the trick, you may have a misadjusted or faulty fill ... the waterlevel a half inch below the top of the overflow tube inside the tank." ...

Emergencies - Overflowing toilets - Toiletology 101

www.toiletology.com/emergenc.shtml

You can't just lower the water level in the tank; you need to displace some of ... and the ballcock and flapper are working properly and shut off when the tank is full. ... The bowl is filled with the water that goes into the overflow pipe. ... Unfortunately, when a toilet bowl is clogged and the water level rises and doesn't flush the ...

check to see if waster continues to run into the bowl after the plunger has returned to stop water flowing. If it is a slow leak then replace the flush washer on the stopper plunger.

you have a blockage maybe outside in your shores

Sorry for problem with new toilet.
You say water is leaking out of the bowl?

Toilets have 2 parts:
1) Tank: where water is stored for the flush and is sealed with a flapper.
2) Bowl: where water flushes down.

a) If tank is leaking water, then flapper is suspect. Replace flapper and see if that works.
Lift up flapper and run finger around rim to see if there is a rough spot that would indicate flush valve is defective, and needs replacement.
See typical flush valve

b) If bowl is leaking, that is very unusual and would indicate a crack in the porcelain.

If installer sold you the toilet, it is his responsibility to make good on product.
All products are guarantee against workmanship flaws.

Check to be sure small tube is flowing inside the ovefow tube. This is the water that flushes the rim holes, and refills the bowl. If you don't have flow clean or replace the float valve.

1- Check ports out under rim all round bowl.

2-Check tank fill level for required amount to with in 5/8" to top of over flow tube.

3-Make sure 1/4" fill tube is connected to over flow tube. From fill valve to overflow tube.

Below is a few details to go by I hope will be helpful for you to take care of this problem.


Under the rim of the bowl check the ports and make sure they are not stopped up. You can open them up with nail or pin to clean out ports.
Next check tank level and make sure the fill valve has a line run from it to top of the overflow tube. This line allows water to goe to bowl and tank to fill required amount needed.
Water in tank should be within 5/8" to top of over flow tube.

If there is a air emiten valve on vent ? Remove it than try to see if it works properly. If this works you will need pipe vent outside

If very little water is used on initial flush, The bowl is functioning as a tank for second thorough flush. The high water level cannot stay high in the bowl while in motion or you would have a mess ion start and stops.