One of the common problems in the toilet is that the toilet tank simply does not fill with water. This kind of malfunction must be promptly eliminated due to the fact that it can cause a significant decrease in bathroom hygiene, as well as the appearance of an unpleasant odor.

The sources of this problem can be a large number of different factors. To identify them, you first need to understand the design of the drain tank itself. Only after this will it be possible to talk about what needs to be done to fix this problem yourself.

General characteristics

The principle of operation of the cistern is entirely based on the law of gravity. It is due to this that the water collected in the tank, after pressing the release button, is released into the toilet at the required speed.

The mechanism that is responsible for the collection of water into the tank and the draining process is called shut-off valves. The largest element of this design is the float. It is he who is responsible for the flushing mechanism. It is necessary to control the water level.

After the release button is pressed, the amount of water inside the container decreases and the float lowers. Due to this, the shut-off valve opens, through which water is poured again.

At the same time, float valves vary in position in the tank. So, there are side and bottom options.

Also, such a device has a drain and overflow system, which is a whole complex of elements.

It does not allow water to accumulate more than the set value in order to prevent it from pouring out of the tank into the bathroom.

The drain mechanism works as follows:

1. First, the required water level is reached, after which the float floats up, and the rocker arm rises behind it.
2. During this, the rocker itself turns and presses the valve, which shuts off the flow of water. When the required amount is collected in the tank, the flow stops due to the tight blocking of the channel.

Take into account: To change the maximum level of liquid that will be collected in the drain system, simply bend the rocker arm a little.

The trigger mechanism is a button, most often located on the toilet lid, and in some models (especially old ones) it is a chain located in the body assembly. But the first option is more common, since it is both more convenient and compact.

There is also a third option, where the tank is built into the wall and a button simply peeks out of it. It looks very aesthetically pleasing and is economical in itself, but if it is necessary to carry out repairs, this option is extremely inconvenient.

Types of breakdowns

The most common reasons why water has stopped flowing into the toilet cistern are:

1. 1. No water supply. This is a very common reason when there is simply no water in the tap. Therefore, in this case, the tank mechanism will have nothing to do with it.
   2. Rust in the filter. The reason here is that over time, the filter in the system becomes clogged, after which the water flows more and more slowly, and then stops flowing altogether. This can be corrected simply by cleaning the filter, after which the water will flow again with the required force.
   3. Float misalignment. Most often it occurs in fairly old models due to the fact that the mechanism has already become loose and the float has moved to the side after flushing, thus, after the water has left, it does not go down. Here it will be enough to simply put it in its original place.

1. Exhaust valve wear. In cases where the age of the tank is significant, this may mean failure of the entire mechanism. To solve this problem, it is necessary to completely replace the exhaust valve.
2. Contamination of the mechanism. Over time, mucus and plaque form on the internal elements of the tank, which prevent them from properly performing their respective functions. To resume operation of the device, you need to remove the mechanism and completely clean it.
3. Setting up the intake tract. If, during the assembly of the system, the elements in it were fastened too tightly, the water will flow very slowly and for a long time. This issue can be resolved by simply loosening certain fasteners.

If you think that certain parts are faulty, there is no need to try to repair them or call repairmen. The fact is that shut-off valves are inexpensive, so by purchasing new ones, you can save a lot of money that would have been spent on the work of a plumber.

Replacement

To replace fittings, it is advisable to first select the correct option. In this case, you need to take into account the features of your current mechanism and try to choose a similar one.

If you have any doubts, you should ask the seller for advice.

After purchasing all the parts, you can begin the installation process itself:

1. First you need to turn off the water either at the riser, or specifically at the pipe from which the hose goes to the toilet.
2. Next, the button is removed, and then the tank lid.
3. Now the liner and drain column are disconnected. All this needs to be done in parts.
4. After this, the tank itself is removed, to do this, its fasteners are unscrewed and taken to a convenient place where further work will be carried out on it.
5. Next, we remove all the insides of the old mechanism from it, clean the walls with hot water and install new elements.
6. At the end, we mount the tank back to the place where we connect it to the water supply and toilet.

It is worth noting: if the installation and connection of the new mechanism was carried out correctly, everything will work, otherwise you need to call a specialist, who will connect everything correctly himself.

Such malfunctions in the operation of the tank are far from a tragedy and a problem that requires large expenses to solve. However, if you do not have experience and skills in working with such mechanisms, you should not try to fix the system yourself; it is better to immediately call a plumber so as not to cause even more damage.

Watch the video in which an experienced user explains in detail what to do if water does not fill the toilet tank:

There are many factors that influence which water freezes faster, hot or cold, but the question itself seems a little strange. The implication, and this is known from physics, is that hot water still needs time to cool to the temperature of the cold water being compared in order to turn into ice. This stage can be skipped, and, accordingly, she wins in time.

But the answer to the question of which water freezes faster - cold or hot - outside in the cold, any resident of northern latitudes knows. In fact, scientifically, it turns out that in any case, cold water is simply bound to freeze faster.

The physics teacher, who was approached by schoolboy Erasto Mpemba in 1963, thought the same thing with a request to explain why the cold mixture of future ice cream takes longer to freeze than a similar, but hot one.

“This is not universal physics, but some kind of Mpemba physics”

At that time, the teacher only laughed at this, but Deniss Osborne, a professor of physics, who at one time visited the same school where Erasto studied, experimentally confirmed the presence of such an effect, although there was no explanation for it then. In 1969, a joint article by these two people was published in a popular scientific journal, who described this peculiar effect.

Since then, by the way, the question of which water freezes faster - hot or cold - has its own name - the Mpemba effect, or paradox.

The question has been around for a long time

Naturally, such a phenomenon took place before, and it was mentioned in the works of other scientists. Not only the schoolchild was interested in this issue, but Rene Descartes and even Aristotle also thought about it at one time.

But they began to look for approaches to solving this paradox only at the end of the twentieth century.

Conditions for a paradox to occur

As with ice cream, it's not just plain water that freezes during the experiment. Certain conditions must be present in order to start arguing about which water freezes faster - cold or hot. What influences the course of this process?

Now, in the 21st century, several options have been put forward that can explain this paradox. Which water freezes faster, hot or cold, may depend on the fact that it has a higher evaporation rate than cold water. Thus, its volume decreases, and as the volume decreases, the freezing time becomes shorter than if we take the same initial volume of cold water.

It's been a while since you defrosted the freezer.

Which water freezes faster and why this happens can be influenced by the snow lining that may be present in the freezer of the refrigerator used for the experiment. If you take two containers that are identical in volume, but one of them contains hot water and the other cold, the container with hot water will melt the snow underneath, thereby improving the contact of the thermal level with the wall of the refrigerator. A container of cold water cannot do this. If there is no such lining with snow in the refrigerator compartment, cold water should freeze faster.

Top - bottom

Also, the phenomenon of which water freezes faster - hot or cold - is explained as follows. Following certain laws, cold water begins to freeze from the upper layers, when hot water does the opposite - it begins to freeze from the bottom up. It turns out that cold water, having a cold layer on top with ice already formed in places, thus worsens the processes of convection and thermal radiation, thereby explaining which water freezes faster - cold or hot. Photos from amateur experiments are attached, and this is clearly visible here.

The heat goes out, rushing upward, and there it meets a very cool layer. There is no free path for heat radiation, so the cooling process becomes difficult. Hot water has absolutely no such obstacles in its path. Which one freezes faster - cold or hot, what determines the likely outcome? You can expand the answer by saying that any water has certain substances dissolved in it.

Impurities in water as a factor influencing the outcome

If you don't cheat and use water with the same composition, where the concentrations of certain substances are identical, then cold water should freeze faster. But if a situation occurs where dissolved chemical elements are present only in hot water, and cold water does not have them, then the hot water has the opportunity to freeze earlier. This is explained by the fact that dissolved substances in water create crystallization centers, and with a small number of these centers, the transformation of water into a solid state is difficult. It is even possible that the water will be supercooled, in the sense that at sub-zero temperatures it will be in a liquid state.

But all these versions, apparently, did not completely suit the scientists and they continued to work on this issue. In 2013, a team of researchers in Singapore said they had solved an age-old mystery.

A group of Chinese scientists claim that the secret of this effect lies in the amount of energy that is stored between water molecules in its bonds, called hydrogen bonds.

The answer from Chinese scientists

What follows is information, to understand which you need to have some knowledge of chemistry in order to understand which water freezes faster - hot or cold. As is known, it consists of two H (hydrogen) atoms and one O (oxygen) atom, held together by covalent bonds.

But also the hydrogen atoms of one molecule are attracted to neighboring molecules, to their oxygen component. These bonds are called hydrogen bonds.

It is worth remembering that at the same time, water molecules have a repulsive effect on each other. Scientists noted that when water is heated, the distance between its molecules increases, and this is facilitated by repulsive forces. It turns out that by occupying the same distance between the molecules in a cold state, they can be said to stretch, and they have a greater supply of energy. It is this energy reserve that is released when water molecules begin to move closer to each other, that is, cooling occurs. It turns out that a greater reserve of energy in hot water, and its greater release when cooling to sub-zero temperatures, occurs faster than in cold water, which has a smaller reserve of such energy. So which water freezes faster - cold or hot? On the street and in the laboratory, Mpemba's paradox should occur, and hot water should turn into ice faster.

But the question is still open

There is only theoretical confirmation of this solution - all this is written in beautiful formulas and seems plausible. But when the experimental data on which water freezes faster - hot or cold - are put into practical use, and their results are presented, then the question of Mpemba’s paradox can be considered closed.

“The simplest stable compound of hydrogen and oxygen,” is the definition of water given by the Concise Chemical Encyclopedia. But, if you look at it, this liquid is not so simple. It has many extraordinary, amazing and very special properties. A Ukrainian aquatic researcher told us about the unique abilities of water Stanislav Suprunenko.

High heat capacity

Water heats up five times slower than sand and ten times slower than iron. To heat a liter of water by one degree, 3300 times more heat is required than to heat a liter of air. Absorbing a huge amount of heat, the substance itself does not heat up significantly. But when it cools down, it gives off as much heat as it took in when heating up. This ability to accumulate and release heat makes it possible to smooth out sharp temperature fluctuations on the surface of the earth. But that's not all! The heat capacity of water decreases as the temperature rises from 0 to 370C, that is, within these limits it is easy to heat it, it will not take much heat and time. But after the temperature limit of 370C, its heat capacity increases, which means that more effort will have to be made to heat it. It has been established: water has a minimum heat capacity at a temperature of 36.790C, and this is the normal temperature of the human body! So it is this quality of water that ensures the stability of the temperature of the human body.

High surface tension of water

Surface tension is the force of attraction and cohesion between molecules. It can be visually observed in a cup filled with tea. If you slowly add water to it, it will not overflow immediately. Take a closer look: you can see a thin film above the surface of the liquid - it prevents the liquid from spilling out. It swells as it is added, and only at the “last drop” will this happen.
All liquids have surface tension, but it is different for everyone. Water has one of the highest surface tensions. Only mercury has more, which is why, when spilled, it immediately turns into balls: the molecules of the substance are tightly “attached” to each other. But alcohol, ether and acetic acid have much lower surface tension. Their molecules are less attracted to each other and, accordingly, that is why they evaporate faster and spread their odor.

High latent heat of vaporization

Photo by Shutterstock

It takes five and a half times more heat to evaporate water than to boil it. If it were not for this property of water - to evaporate slowly - many lakes and rivers would simply dry up in the hot summer.
Globally, a million tons of water evaporate from the hydrosphere every minute. As a result, a colossal amount of heat enters the atmosphere, equivalent to the operation of 40 thousand power plants with a capacity of 1 billion kW each.

Extension

As the temperature decreases, all substances contract. Everything, but not water. Until the temperature drops below 40C, the water behaves quite normally - becoming slightly denser, it reduces its volume. But after 3,980C it behaves, or rather, it begins to expand, despite the decrease in temperature! The process goes smoothly up to a temperature of 00C until the water freezes. As soon as ice forms, the volume of already solid water increases sharply by 10%.

Mpemba effect(Mpemba's Paradox) - a paradox that states that hot water under some conditions freezes faster than cold water, although it must pass the temperature of cold water in the process of freezing. This paradox is an experimental fact that contradicts the usual ideas, according to which, under the same conditions, a more heated body takes more time to cool to a certain temperature than a less heated body to cool to the same temperature.

This phenomenon was noticed at one time by Aristotle, Francis Bacon and Rene Descartes, but it was only in 1963 that Tanzanian schoolboy Erasto Mpemba discovered that a hot ice cream mixture freezes faster than a cold one.

As a student at Magambi High School in Tanzania, Erasto Mpemba did practical work as a cook. He needed to make homemade ice cream - boil milk, dissolve sugar in it, cool it to room temperature, and then put it in the refrigerator to freeze. Apparently, Mpemba was not a particularly diligent student and delayed completing the first part of the task. Fearing that he would not make it by the end of the lesson, he put still hot milk in the refrigerator. To his surprise, it froze even earlier than the milk of his comrades, prepared according to the given technology.

After this, Mpemba experimented not only with milk, but also with ordinary water. In any case, already as a student at Mkwava Secondary School, he asked Professor Dennis Osborne from the University College in Dar Es Salaam (invited by the school director to give a lecture on physics to the students) specifically about water: “If you take two identical containers with equal volumes of water so that in one of them the water has a temperature of 35°C, and in the other - 100°C, and put them in the freezer, then in the second the water will freeze faster. Why?" Osborne became interested in this issue and soon, in 1969, he and Mpemba published the results of their experiments in the journal Physics Education. Since then, the effect they discovered has been called Mpemba effect.

Until now, no one knows exactly how to explain this strange effect. Scientists do not have a single version, although there are many. It's all about the difference in the properties of hot and cold water, but it is not yet clear which properties play a role in this case: the difference in supercooling, evaporation, ice formation, convection, or the effect of liquefied gases on water at different temperatures.

The paradox of the Mpemba effect is that the time during which a body cools down to the ambient temperature should be proportional to the temperature difference between this body and the environment. This law was established by Newton and has since been confirmed many times in practice. In this effect, water with a temperature of 100°C cools to a temperature of 0°C faster than the same amount of water with a temperature of 35°C.

However, this does not yet imply a paradox, since the Mpemba effect can be explained within the framework of known physics. Here are some explanations for the Mpemba effect:

Evaporation

Hot water evaporates faster from the container, thereby reducing its volume, and a smaller volume of water at the same temperature freezes faster. Water heated to 100 C loses 16% of its mass when cooled to 0 C.

The evaporation effect is a double effect. Firstly, the mass of water required for cooling decreases. And secondly, the temperature decreases due to the fact that the heat of evaporation of the transition from the water phase to the steam phase decreases.

Temperature difference

Due to the fact that the temperature difference between hot water and cold air is greater, therefore the heat exchange in this case is more intense and the hot water cools faster.

Hypothermia

When water cools below 0 C, it does not always freeze. Under some conditions, it can undergo supercooling, continuing to remain liquid at temperatures below freezing. In some cases, water can remain liquid even at a temperature of –20 C.

The reason for this effect is that in order for the first ice crystals to begin to form, crystal formation centers are needed. If they are not present in liquid water, then supercooling will continue until the temperature drops enough for crystals to form spontaneously. When they begin to form in the supercooled liquid, they will begin to grow faster, forming slush ice, which will freeze to form ice.

Hot water is most susceptible to hypothermia because heating it removes dissolved gases and bubbles, which in turn can serve as centers for the formation of ice crystals.

Why does hypothermia cause hot water to freeze faster? In the case of cold water that is not supercooled, the following happens. In this case, a thin layer of ice will form on the surface of the vessel. This layer of ice will act as an insulator between the water and the cold air and will prevent further evaporation. The rate of formation of ice crystals in this case will be lower. In the case of hot water subjected to supercooling, the supercooled water does not have a protective surface layer of ice. Therefore, it loses heat much faster through the open top.

When the supercooling process ends and the water freezes, much more heat is lost and therefore more ice is formed.

Many researchers of this effect consider hypothermia to be the main factor in the case of the Mpemba effect.

Convection

Cold water begins to freeze from above, thereby worsening the processes of heat radiation and convection, and hence heat loss, while hot water begins to freeze from below.

This effect is explained by an anomaly in water density. Water has a maximum density at 4 C. If you cool water to 4 C and put it at a lower temperature, the surface layer of water will freeze faster. Because this water is less dense than water at a temperature of 4 C, it will remain on the surface, forming a thin cold layer. Under these conditions, a thin layer of ice will form on the surface of the water within a short time, but this layer of ice will serve as an insulator, protecting the lower layers of water, which will remain at a temperature of 4 C. Therefore, further cooling process will be slower.

In the case of hot water, the situation is completely different. The surface layer of water will cool more quickly due to evaporation and a greater temperature difference. In addition, cold water layers are denser than hot water layers, so the cold water layer will sink down, raising the warm water layer to the surface. This circulation of water ensures a rapid drop in temperature.

But why does this process not reach an equilibrium point? To explain the Mpemba effect from this point of view of convection, it would be necessary to assume that the cold and hot layers of water are separated and the convection process itself continues after the average water temperature drops below 4 C.

However, there is no experimental evidence to support this hypothesis that cold and hot layers of water are separated by the process of convection.

Gases dissolved in water

Water always contains gases dissolved in it - oxygen and carbon dioxide. These gases have the ability to reduce the freezing point of water. When water is heated, these gases are released from the water because their solubility in water is lower at high temperatures. Therefore, when hot water cools, it always contains less dissolved gases than in unheated cold water. Therefore, the freezing point of heated water is higher and it freezes faster. This factor is sometimes considered as the main one in explaining the Mpemba effect, although there is no experimental data confirming this fact.

Thermal conductivity

This mechanism can play a significant role when water is placed in the refrigerator compartment freezer in small containers. Under these conditions, it has been observed that a container of hot water melts the ice in the freezer underneath, thereby improving thermal contact with the freezer wall and thermal conductivity. As a result, heat is removed from a hot water container faster than from a cold one. In turn, a container with cold water does not melt the snow underneath.

All these (as well as other) conditions were studied in many experiments, but a clear answer to the question - which of them provide one hundred percent reproduction of the Mpemba effect - was never obtained.

For example, in 1995, German physicist David Auerbach studied the effect of supercooling water on this effect. He discovered that hot water, reaching a supercooled state, freezes at a higher temperature than cold water, and therefore faster than the latter. But cold water reaches a supercooled state faster than hot water, thereby compensating for the previous lag.

In addition, Auerbach's results contradicted previous data that hot water was able to achieve greater supercooling due to fewer crystallization centers. When water is heated, gases dissolved in it are removed from it, and when it is boiled, some salts dissolved in it precipitate.

For now, only one thing can be stated - the reproduction of this effect significantly depends on the conditions under which the experiment is carried out. Precisely because it is not always reproduced.

O. V. Mosin

Literarysources:

"Hot water freezes faster than cold water. Why does it do so?", Jearl Walker in The Amateur Scientist, Scientific American, Vol. 237, No. 3, pp 246-257; September, 1977.

"The Freezing of Hot and Cold Water", G.S. Kell in American Journal of Physics, Vol. 37, No. 5, pp 564-565; May, 1969.

"Supercooling and the Mpemba effect", David Auerbach, in American Journal of Physics, Vol. 63, No. 10, pp 882-885; Oct 1995.

"The Mpemba effect: The freezing times of hot and cold water", Charles A. Knight, in American Journal of Physics, Vol. 64, No. 5, p 524; May, 1996.