What is a toilet refill tube?
The toilet refill tube is one of the most impactful items for the toilet. The toilet refill tube is considered the heart of the toilet. It is the main source of an element that is responsible for filling the tank of the toilet in a rapid fast manner. The refill tube is connected with a continuous water supply line that allows water to run into the tank.
How a toilet refill tube works:
Normally the refill tube is attached with the float rod adjustment screw, the trip lever, and an overflow tube. When you turn on the water supply valve, then water enters the refill tube and fills the tank. There is a close connection between the refill tube and the overflow tube. When water tends to inundate the tank, the overflow tube controls the flow of water, and the refill tube is immensely connected to this process.
What does the refill tube do in a toilet?
The refill tube is more crucial than you may ever realize. It is directly linked with the refill valve and the overflow tube. The main responsibilities of the refill tube are described in a detailed manner, 
- The refill tube inspects the entrance of the particular amount of water into the toilet tank.
- It is directly attached to the overflow tube, so it is responsible for no water or overflow in the tank.
- The refill tube is associated with the entire flushing mechanism, and if it fails due to the unstable or defective posthumous, the toilet may lose its optimum efficiency.
Where does the refill tube go in the toilet tank?
The refill tube is the main component that allows water into the toilet’s tank. It prevents the overflowing of water in the tank. The main mechanics lies in between the connection of the refill tube and the overflow tube. The fill tube is a tiny little rubber tube running from the fill valve to the interior portion of the overflow valve. Literally, water enters the tank of the toilet and refills the bowl. The fill tube refills the bowl when water flows deep down the overflow valve connected to the pipe’s backside. When the water level soars impressively, the ball rises high to switch the water if the tank seems full to its brim. It is an important consideration that the refill tube must be high from the overflow tube; otherwise, the tank won’t be filling in a rapid manner.
How to replace or adjust the toilet refill tube?
The process of replacing the toilet refill tube can be mentioned as a gruesome task as it is not a common element of the toilet that needs further replacement. It is mainly the part that is responsible for allowing water to enter the tank of the toilet. For the convenience of the consumers, I will elaborate on the whole replacement procedure in a brief and detailed manner,
Shut off the water supply
As the refill tube is situated inside the toilet tank, it is a must to uncover the toilet tank lid. It would be best if you took off the tank’s lid and put that in a nice and secured place. After you have removed the lid, the next thing you must do is stop the water supply line. You need to turn the nozzle or the water supply valve clockwise. 
Locate the refill valve
Then flush the toilet and remove all the water out of it. Wipe out all the moisture with the help of a nice soft sponge. Then find out the spot where the refill tube is located. Take the bottom end of the refill tube, which is attached to the side of the fill valve. You must twist and turn the end back and forth when ripping it apart and remove it from the fill valve. The refill tube fits over a nipple on the side of the valve. After you have examined the refill tube, make a definitive decision if you should replace it.
Clean the refill valve
A plastic tube inside the refill tube is vulnerable and catches debris too soon. It would be best if you used your finger to unscrew the bolt cap of the refill tube, and there is a pin inside the refill tube that must be replaced to make it workable again. Finally, slide the tube clip of the overflow tube. The end of the refill tube must be pointed inside the overflow tube.
Changing the refill valve
In the next stage, you need to examine the fill valve nipple. Unhook the refill tube’s opposite side from the overflow tube’s upper portion if water is flowing through the fill valve nipple. Check the refill tube if it gathers some sort of debris or dust inside it. If the refill tube gets damaged, then change it as soon as possible. 
After replacing the refill tube, you need to turn on the water supply again and put the lid back in the initial location. That’s how without the help of a professional, you can easily replace the refill tube.
Hi, this is Robert Crossan, the owner of this website, has 17 years of experience in the installation, maintenance, and repair of toilets and plumbing systems. After completing the Level 2 Basic Plumbing course in 2005, I started working in both domestic and commercial buildings as a professional plumber. So I can figure out the core difference between different toilet models and brands. It also helped me monitor their work performance and setbacks.