The Science of a toilet

The system that empties the water and waste and refills the tank is relatively easy to understand. Water will always seek level its self. Inside the base of the bowl is an “S” trap. As the water is released into the bowl, the water will rise and then pour over the top of the “S”. As this happens, it will cause a siphoning affect and pull the water and waste through the “S” trap. This will continue until the speed of the water slows and the siphoning stops. Then water will continue to pour into the tank to the level of the top of the “S” trap.

There are two main areas of a toilet, the bowl and the tank. The bowl has no mechanical or moving parts except the seat and the seat cover. The tank has four areas.

1. There is the Lever that is connected to the handle you press to flush the toilet. On the inside of the tank, the lever raises and lifts a flapper with a lift chain that releases the water into the tank.

2. The Flapper is a rubber piece that covers the flush valve seat. This is what keeps the water in the tank until flushing. When it is raised to flush the toilet, it will stay up until the tank is empty and then fall back to seal the flush valve seat.

3. There is another non-mechanical part and that is the overflow tube. The overflow tube is a tube vertically in the tank and is a safety device. If the Fill Valve does not shut off, once the water reaches the level of the top of the tube, the water will pour into the tube instead of overflowing the tank. This is also where water will flow from the valve to refill the bowl and the end of the flush cycle.

4. The main device is the Toilet Filling Valve. This is a device that allows water to fill the tank. The water supply is connected to the valve through the bottom of the tank. At the top is the actual valve which controls the operation of allowing water to run to fill the tank. Water flow stopped by some device that will float with the water level and once it reaches the desired level, it will close the valve to stop the water flow filling the tank. While filling the tank, there is a hose that is comes from the valve to the top of the overflow tube to refill the bowl. With this basic knowledge you will better understand the causes of most problems and what needs to be adjusted or replaced.

Before you start any repairs, you should familiarize yourself with the parts and also locate the water shutoff valve. Many homes have a water supply valve at the wall that will shut off water flow to the toilet. Locate this and test it to be sure it works. Also find the main water shutoff valve for the house in case the one by the toilet is not functional.

Running Toilet

One of the most common problems is a running toilet. There are two main reasons to cause this. The first is the Flapper Valve is not sealing the Toilet Filling Valve. Flapper Valves are made of rubber and over time can decompose, warp or crack. Since it is not sealing correctly, water will leak into the tank. There are different styles so it is advisable to remove the defective piece and take it to the store to match the correct replacement.

To replace the flapper, first turn off the water supply to the toilet. The existing flapper is usually easy to remove just look where it connects to its base.

Another reason you might have a running toilet is the valve is not shutting off before the water reaches the top of the overflow tube. This level should be approximately 1/8” to ¼” below the top edge of the tube. There are two reasons this can happen:

1. The part of the Toilet filling valve that floats and turns off the valve is not low enough to stop the water before it reaches the desired level. Just adjust the float to a lower position so it will stop the water at a lower level.

2. The other reason is the valve is worn and not stopping the water exiting the valve. Some valves have replacement “O” rings. You just need to turn off the water supply and remove the top of the valve. If there is no replacement part you will need to replace the Flush Valve Unit.

There are replacement kits that have easy to follow directions. As always, turn off the water supply before starting this repair. The repair consists of disconnecting the water supply pipe from the bottom of the tank. Then you unscrew the bold attaching the valve to the tank. Then detach the fill tube that is clipped to the overflow tube and lift the old valve from the tank. With the replacement valve, just reverse the process that you used to remove the old valve. When you turn on the water supply, make sure there is not any leaking. If there is, tighten the bolt or the end of the supply line a little more, being careful not to over tighten. Both should be about a quarter to a half turn past finger tightness. All you have to do now is turn on the water supply and adjust the float to stop the water at a level just below the top of the overflow tube. This will be on the instructions that came with the new valve.

Broken Flush Handle

There is another problem that is common and easy to replace. That is the handle/lever. The handle is often made of plastic and with all the use, it sometimes will crack. This mechanism is bolted on the inside of the tank.

First remove the chain that connect the lever to the flapper and then gently unscrew the bolt holing it to the tank. When purchasing a replacemnt look to make sure the replacement is for the same type of tank you have. It can be a front mounted or a side mounted handle. Again, just reverse the steps you used to remove the broken handle.

Leaking Toilet Bowl

The last common problem is when you see water leaking from under the bowl. This will happen when the toilet is flushed and is usually just a small amount of water. Unless someone hit the bowl with something hard and cracked it, and there is no water coming from where the tank connects to the bowl, it is probably coming from under the bowl.

This can happen over time from vibrations or movements of the bowl while in use. The cause is probably because the bolts that hold the bowl to the floor have loosened a little allowing the toilet to rock. Below the toilet, where the water exists the toilet and enters the drain pipe in the floor there is a “Wax Ring.” This is a ring made of a semi hard wax. When the toilet is installed, the wax ring is placed over the drain hole and the toilet is pressed down causing the wax to seal the connection.

This is not a difficult repair to perform. First turn off the water supply to the toilet. Then flush the toilet to empty the tank. Then using a plunger, try to remove as much water from the bowl as possible. You will not be able to remove all, so be prepared with a mop or towels to absorb the rest of the water that will come out when you disconnect the bowl from the floor. Then disconnect the water supply line to the tank and remove then loosen the bolts connecting the bowl to the floor. Once the nuts are removed, lift the toilet straight up and off the drain pipe. With gloves and a putty knife, remove the existing was ring.

Next place the new wax ring over the drain and carefully place the toilet back over the drain, making sure the bolts are through the holes in the base. Press the bowl firmly down to squeeze the wax ring and seal the connection. Do not turn the bowl as pressing and use a minimal of rocking motion. Then tighten the bolts to secure the bowl tightly to the floor. Now reconnect the water supply line to the toilet. All that is left is to turn on the water supply and let the tank fill. Once full, flush the toilet to prove you did a wonderful job and there is no more leak.

As you will learn, these are easy repairs that will not cost a lot of money. With you doing these repairs, you will save the expense of calling a plumber.