It takes a long time to fill the tank

5 Year warranty on that. Get it replaced.

Sounds like the valve in it has gone bad. I am not as familiar with this particular part.

Leave the fill line in position that works otherwise the siphoning will continue in the other position.

My sister has a two year old Jacuzzi toilet that worked fine until a few months ago. Then it started to take 10 minutes to shut off after each flush. I lifted the tank cover and immediately saw the problem; at least 90% of the refill water was going into the refill pipe instead of the tank. Upon examination I discovered that the plastic part that holds the flexible refill tube to the vertical refill pipe was broken. This part not only holds the refill tube in place, it also has a small orifice at the end to restrict the flow into the pipe. The part was broken in such a way as to let nearly all the water go into the refill pipe instead of the tank, hence it would run for 10 minutes after the toilet bowl was full and waste all that water. I found a small coarse thread stainless steel screw that fit into the plastic attachment piece to help plug the orifice and cut down the amount of water going to the refill pipe. Now the toilet flushes and refills in less than 2 minutes. I'm in the process of trying to find a replacement for that part but so far no luck.

There's a lot of variety in the works in the toilet tank. Assuming this is not a pressure-assisted toilet-----First understand the three valves are: 1. The shutoff valve - on the supply line coming into the toilet tank. 2. The fill valve - inside the tank, opens with the float descends, closes when the tank fills up. 3. The flush valve - inside the tank on the bottom. Common old style is a flapper on a pivot. Yours may operate straight up and down rather than on a pivot.
Three very common problems are---- 1. The chain that connects the handle to lift the flush valve is getting caught, not allowing the flush valve to close. 2. There is problem with the flush valve being able to get a good seal when it closes - could be debris or misalignment. 3. The fill valve is not closing when the tank is full, could need adjustment or there is debris preventing the valve to seat. . Here's are some steps to diagnose---- close the shutoff valve. Wait a few minutes as you watch the level in the tank. If the water level decreases, you have problem with the flush valve. To confirm the fill valve as the problem, turn the shutoff valve back on. Lift up on the float that is supposed to turn off the fill valve. If it shuts off, you should be able to adjust it - most have a +/- plastic adjustment screw. But if raising the float by hand only slows it down, you have problem with the seating of the fill valve - which can sometimes be cleaned, but more often would need to be replaced.
I hope this is helpful. Thanks for using FixYa.

if the toilet is old or not cleaned proper, the water jets that shoot the water into the bowl might be clogged. If the jets are clogged with moldor hard water build up the toilet will not flush proper. If you can take a 3 gallon bucket of water and pour straight into the bowl and it flushes fine you have a water pressure problem as described above. the problem also might be that your water inlet system is not letting in enough water to fill the tank. If this is the problem you need to replace the water inlet mechanisim, such as a fluid master. If you use a blue water device that hangs on the side of the tank in the back of the toilet you might have a peice of it under the flapper that takes the water to the bowl when being flushed. Check under the flapper if you put cleaners in the tank.

More then likely the power valve in your flush master ball valve is out.. Replace flush valve and should fix problem. Home depot sell fluid master for like 7.50

Yes, it will run up your bill! Sounds like the float is hanging up. Take tank lid off and flush, watch the float and if your tank fills quickly but does not stop, bend the float arm to angle the float down further, this should allow your water to stop coming in much quicker. The other possibility could be if the plug at the bottom does not seal correctly after flushing, if so, the water will leak until the plug sits down all the way.

Remove the tank lid and look at the fill valve. Is it a yellow valve?
This fill valve is common on the Toto Toilets and can easliy plug with debrie.

They can be disassmbled and cleaned. however, I usually just replace the valve with Fluid Master Fill valve.
You will also want to check the water coming into the toilet by turning off the water that supplies the toilet and disconnecting the water supply line. After removing the water supply line turn on the water at the valve to make sure that the water is flowing properly. Check the supply line also to make sure it is not plugged.
Be sure and place a small container to catch the water that will come from the valve. A towell will also help from making too much of a mess.
If the Supply line and the valve are clear the problem is in the fill valve.
The G-Max system denotes the Flushiing system which is a 3" flapper that allows the water from the tank to flow into the bowl quicker.
Good Toilets!

sanray