Vitra elongated Toilet when flushed, water does not flow through the rubber hose to the overflow. Water enters the tank at the top of the valve and flows into the tank like a waterfall with the noise of a waterfall

That's an interesting one! Does the flush valve close properly so the tank can refill? Does the float valve allow the tank to refill fully, to near the top of the overflow? That can be adjusted, if it doesn't.

Check fhe flush valve - you may have an obstruction under it. Also check the water port from the bowl side - feel up inside the port for obstructions or buildup of hard water deposits.

WASH YOUR HANDS THOROUGHLY afterwards.

The overflow pipe should be attached to a small clip that holds it in position over the over flow pipe. If it is loose or attached to the outside it will do what yours is doing.

If I understand correctly, the tank that holds water is not filling up with water.

1) If this is the problem, then you need new toilet fill valve.
Or clean sediment out of existing fill valve by removing and soaking in CLR calcium rust lime.

To replace fill valve:
Look at water supply line coming into tank.
Supply line connects to fill valve.

Buy new fill valve at home center, hardware store, or walmart, or online.
There are two nuts connected to valve. Each nut has companion rubber washer

One nut & washer seal water supply line to tank.
Second nut & washer seal valve to tank.

2) If water tank is full of water, but water does not flow rapidly into bowl when you push flush lever, then your toilet is clogged with sediment.

To solve sediment problem when flush water will not flow rapidly into tank, then buy CLR calcium lime rust.
Pour CLR down into overflow tube located inside water tank.
Make a funnel by cutting off bottom of water bottle, or cut paper cup into a funnel.
Pour cup-full after cup-full of CLR into overflow tube until sediment and CLR are coming out all flush holes located under-rim on bowl.

3) Add a comment for more free help.
Also take advantage of fixya phone service.
For a price, expert speaks with you over phone while you work on timer or any do-it-yourself project.
Fixya is always less expensive than a service call.

If you have a supply shut off to fixture shut it off and disconnect supply line from inlet to toilet . If your supply line to toilet is a flexible line then bend it so that you can direct water to small container. Slowly turn valve on to see what flow rate is at that point. If flow rate is not good then I would shut water off to house and replace valve. If flow rate to toliet is good I would reccomend you replace flush vallve. To do this shut off water supply to toilet. Disconnect supply nut to bottom of flush valve. There will be a retaining nut that holds flush valve in place in toilet tank. Remove flush valve after removing fill tube from flush valve to overflow tube. Replace with toto replacement valve or use Fluidmaster 400A. Instructions on box of 400A are easy to follow and if you have flex connector you won't need supply line washer. I would reccomend that before you install new valve that you put rubber gasket on shank of valve and slid it about halfway up the shaft. Make sure that inside of tank is dry and use a small bead of silicon caulking on top and bottom side of shaft gasket. slid gasket the rest of the way on valve shank,install in tank and put on retaing nut hand tight. Push down on top of valve and using channel lock pliers finish tightening nut securely.You may need to reach into tank and grasp valve body to stop it from turning. There are other things you can do if you have a working supply valve. Shut off valve and remove screws that hold top of valve in place and remove and clean surfaces. You can turn valve on slowly to help flush out any rust or mineral deposits. I hope this is of some help to you. Thanks

the rubber flapper on the bottom of the tank is not seating on the drain and it is allowing water to leak out to the sewer, also check to see if water is too high in the tank and flowing out of the center overflow tube, if so adjust the height of the water level

maybe by shortening the chain length on the flapper valve might help

The water level in the bowl is determined by the built in trap in the back of the bowl. Water is allowed to enter the toilet and it then "over flows" the p trap in the back when flushed. Once it's flowing, it syphons the water out of the bowl. While the tank is re-filling, a small portion of water should be running down the overflow from the small hose clamped onto the overflow This rinses the inside of the bowl, as well as helps-refill the bowl. Be sure that hose is directed inside the overflow tube. To see what the max water level in the bowl can be, add some water from a cup or glass. Once it's full you can keep adding and it won't get any higher. This will be the max level you can expect.

Hose in tank it has a clip to secure it to a fill tube in center of tank to let water fill down tube . If it is just stuck down in it or loose it has to much pressure and will spray every where.

I don't exactly know what you mean so i will cover all the basics. The fill valve sends fills water in 2 locations. 1) the fill valve fills at the low end (from the bottom to the top) of the tank. This is the flush water level. It needs to be stopped by a float switch before the water overflows into the over flow tube.
2) the fill valve fills water via a small tube at the top of it which this tube NEEDS to be pointed into the overflow tube with a high arch. THIS water is filling your toilet bowl section to proper flushing height. If your water in your bowl does not reach proper height and someone removes this tube to aim it into the tank where the other water is stored, THEN you may have the problems you described and you will need to do several flushes to remove waste.
SO to reiterate 1) make sure your float cuts off and stops the filling cycle before the water flows into the over flow tube. This is done from 1 or 2 adjustment screws. and 2) make sure the small black tube is aimed down into the over flow tube with a good arch. The arch prevents back siphon.

It sounds like the flapper is not seating after it has been raised with the chain. I have had this problem. Take the lid off the tank and see if the flapper, the rubber thing that covers the hole in the bottom of the tank, is hanging up on something. On mine, the chain was too long and fell down the hole and kept the rubber flapper from sealing the hole.
If the tank is filling up with water and the water keeps flowing in and going down the overflow, then the fill valve needs to be adjusted so that the water shuts off about one half inch below the top of the overflow tube. Best of Luck