Does your old toilet flush show signs of wear? Knowing that the flush alone accounts for 20% of your water consumption, it’s time to change it. But a problem arises: how to choose the right flush mechanism? To avoid getting the wrong model, check what type of mechanism you have. And to make sure your system is compatible with the one you are going to buy, follow the guide.
How does a toilet flush work?
The flushing mechanism is used to empty the toilet bowl after use. It’s a simple and effective system that stands the test of many daily uses. The cistern of your toilet is connected on one side to the bowl and on the other to the supply tap. To release water when needed, the flushing mechanism kicks in.
In general, a toilet flush is made up of these elements:
- A float which controls the supply valve. When the float goes down, the valve opens; when the float rises, it closes the valve. Simple, basic.
- A system of closing of the tank, which is called the cloche. When you activate the flush, the bell rises, releasing the water contained in the tank. After use, it falls back and closes the evacuation hole again.
- And seal located between the tank and the bowl.
- Everything is operated by a bouton
There are several flush models, several types of float valve supply, etc. Before explaining how to choose a compatible mechanism, here is a small review of the main elements that compose it.
The 2 flush mechanisms are:
There are two types of mechanisms, installed on a tank most often visible, and sometimes recessed.
The bracket flush
This is the most common system. We talk about a “gravity” mechanism, because it just lifts the bell to empty the tank. Water flows all at once, without flow control. The stirrup is the part that operates the bell.
This more sophisticated system uses pressure. This is called a hydropneumatic mechanism. The water is kept under pressure; when you activate the flush, the mechanism releases only the useful quantity. With the flow of water under control, you consume significantly less water. Another advantage: it is suitable for push buttons with remote positioning (in short: the buttons located on the side of the tank). This type of flush is more powerful and efficient than the previous one, but also noisier. But since it saves a lot of water, or gladly forgets about this small inconvenience.
Note that there are also silent mechanisms, designed to reduce the sound of flushing. We appreciate it in night mode. There are also universal mechanisms can be adapted to all tanks. However, it will be necessary to take some measures, especially if your tank is old.
To activate the mechanism: the push button
When you flush the toilet, the flush mechanism engages using the push button. There are three types: the pull tab, the single push button and the double push button.
The zipper and the simple push button
The prehistoric basins still have some, but let’s admit that the zipper is becoming rare. It is a metal rod that pulls vertically. This very inexpensive system has been forgotten because it does not manage the flow of water. With a zipper, forget about saving water.
Like the zipper, simple push button is not expensive to buy. But again, it completely empties the tank as soon as it is activated. You can’t control the flow. In the long run, these two systems are solid but not really water efficient.
The water stop button
A little more advanced, this button allows you to control the flow of water released. As soon as the bowl is clean, you stop the evacuation without waiting for the tank to be completely emptied.
The double push button
With this button, we take a giant leap towards water savings. Two buttons coexist: a large and a small, corresponding to the amount of water you want to release. Heavy cleaning: 6 liters; small cleaning: 3 liters (the ratio can be 9/6 liters, depending on the tank). Corresponding to a hunt double flux, this type of button is more expensive to buy. But when we consider the enormous water savings it allows, we understand why it is (by far) the most widespread today.
Zipper and push button can be directly connected to the flush mechanism. Disadvantage: to change the mechanism, you have to completely disassemble the pull tab to be able to lift the tank cover… When they are connected to the mechanism by a cable, access to the tank is easier. There are also systems combining a cable and a mechanical controla solution that combines the advantages and proves to be rather robust.
Food: what type of float valve?
This faucet manages the water supply. Connected to the water network, it connects to the tank. It is also connected to the float and the flush mechanism. It is he who stops the water when the tank is full. There are two models:
The side float valve
As its name suggests, it is attached to the side of the tank. This faucet, in brass and chrome, is particularly noisy when filling. The good point is that its thread is standard.
The low-mounting float valve
The water supply to the tank is from below. In this way, the filling is much less noisy. The float connected to the tap manages the stoppage of the water supply when the tank is full.
There are two types of floats: floats with the sink and the floats servovalves. These go up along a rack to come and operate the water shut-off valve.
Check the compatibility of the flushing mechanism
Let’s get down to business. To replace the mechanism of your worn flush, a few precautions will help you not to go wrong. To tell the truth, the dimensions of the mechanisms are almost standard. The openings are often quite similar in size, which makes adaptation relatively easy. But if you want to be sure that everything fits the best, here are our tips.
Choose the same brand of equipment
Regardless of the brand of your flush mechanism, take note of it before going to buy another one. Indeed, the plug located at the bottom of the tank, essential in fixing the assembly, is not standard. It is different from one brand to another. If you change brands, you may have to remove the tank.
Check the type of mechanism: cable or bracket?
Recent toilets are often equipped with a stirrup mechanism, fixed to the lid. What complicates the replacement is that you will have to cut the stirrup to adjust it to the correct height. You won’t have this problem with a cable mechanism, since the cover is not attached.
Measure the diameter of the drain hole
Located at the bottom of the tank, it is the orifice through which the water released (delivered) flows towards the bowl. The flushing mechanism is fixed in this hole, which is usually 60 to 80 mm in diameter in recent toilets. But it is possible that your tank is old or of a special model. Our advice: measure it yourself to know the exact size.
Measure the diameter of the hole on the lid
This time, it is a question of checking the size of the opening through which the pull tab or the cable connected to the push button passes. Its diameter is between 16 and 50 mm.
Measure the height of the tank
Recent toilets have a standard size cistern, between 252 and 392 mm. They easily accommodate most flush mechanisms. If your toilet is rather old, measure the height of the tank.
Check the position of the supply valve
Is the water supply valve located on the side of the tank or below?
Check the condition of the float
If it is in good condition, there is no need to buy a flush mechanism kit including a float. If you also need to change the float, take these two criteria into account: its level sound and its system of closing (deferred or not). To choose a model that is not too noisy, it is advisable to choose a model with the NF label. Delayed shutoff saves water by triggering tank filling only after the valve is closed. As the water does not go unnecessarily towards the bowl, this represents a saving of around 7% compared to a conventional float valve.
While you’re at it, take the opportunity to switch to a dual push button mechanism. You will save a lot of water.
Exposed cistern or wall-hung toilet?
In the most common case where your toilets are fitted with a visible cistern, replacing the mechanism will not cause you any major difficulty. Any good handyman can do it. For wall-hung toilets with built-in cistern, the intervention of a plumber is desirable.
Exposed tank? Easy
As we have already seen, the visible tank makes it possible to check the state of each element and to take the necessary measures. You can change the flush mechanism yourself. If you call a plumber, he will change everything: mechanism, float valve, and maybe the bowl too! In any case, ask him to install branded equipment for you. When you have to replace the system in ten years, it will be easier to find the equivalent.
Built-in tank? Not easy
Do you have beautiful designer wall-hung toilets? The tank is therefore embedded in the support frame. On this type of toilet, it is impossible to install a pull mechanism. They are equipped with cable mechanisms, connected to the push button on a vertical plate. Unless you are an excellent handyman, it is best to ask a plumber to replace your flush mechanism. It must be said that the replacement is done blindly; better a professional with a sure hand.
Last tip: don’t forget to turn off the water before dismantling the flushing mechanism!