What you need to know about the fittings for the toilet cistern: characteristics, companies, prices. Toilet valve: types of valves and features of their installation Tank shut-off valve

Plumbing in a home is difficult to repair. And the bathroom with all the accessories is no exception. But there will be no problems if you know the device and the causes of problems with the toilet. Knowing is almost half the battle on the path to skill.

Toilet design

Structurally, a standard toilet consists of two main parts: a drain (flush) cistern and a bowl. These parts are containers, the first of which serves to accumulate water, store it and drain it into the bowl, and the second is connected to a sewer riser where the contents from the bowl are flushed.

Modern types of bowls contain the following elements:

• the bowl itself with fastening ebbs;
• release device;
• plastic seat with cover included.

Bowls for installation in apartments are cast from porcelain or earthenware. Plastic and metal products are installed in non-residential buildings. In old houses there are still cast iron toilets, but they are unlikely to be found on sale.

The outlet from the bowl is designed with the outlet pipe bent upward so that there is always water at the beginning of the bend. A water seal is formed that prevents unpleasant odors from the sewer riser of the house from penetrating into the toilet room.

There are two groups of toilets based on the design of the outlet pipe:

• with a horizontal outlet, when the direction of the pipe is parallel or at a slight angle downward to the floor surface;
• with a vertical outlet, in which the pipe is directed vertically downwards.

The second option has not become widespread in Russia due to standard designs of sewerage installations in residential apartment buildings, which do not make it possible to install toilets of this group. It is suitable for private homeowners who build their homes according to their own designs.

The drain tank is a reservoir for flush water and is always located above the location of the bowl. The higher the tank is installed, the more powerful the flushing water flow and the cleaner the bowl.

The tank in modern plumbing is attached:

• directly on the mounting shelf on the back of the toilet bowl (“compact”, the most popular option);
• to the wall at a certain height from the installation of the bowl (suspended structure);
• hidden in the wall (built-in tank).

There are only two devices inside the tank: a water accumulation system and a drainage system. These devices have shut-off and drain fittings, including a shut-off valve and a filling and water level adjustment valve. This also includes a float and a water drain lever.

Inlet fittings

There are two types of tanks based on water inlet:

• side water inlet, when the inlet of the tank is located on its side in the upper part;
• bottom inlet, suggesting the location of the water inlet from the bottom of the tank.

In flush tanks with a side water supply, a liquid inlet valve is located at the inlet. Connected to the valve is a shut-off device consisting of a horizontally located float on a curved brass lever (rocker arm). In tanks with a bottom water supply, the inlet valve is also located at the bottom inlet, but the float is not located horizontally in the tank, but vertically. In any intake design, the main part of the intake valve is the diaphragm. Occasionally, a piston valve is used instead of a diaphragm valve.

There is nothing complicated about the water drainage mechanism, although there are many modifications associated with saving water. The mechanism drains the existing water supply into the toilet. Part of the drain is the overflow from the tank, which prevents the tank from overflowing in cases where the water inlet valve is faulty. The drain system includes the release valve, release lever (or button), release valve seat, stem, and stem guide.

Mechanism operation

The operating principle of the entire flushing device is no different from the long-used model. The drain from the tank in modern versions of the toilet is absolutely identical to the drain in the corresponding devices of the Soviet era. The liquid in the tank comes from the apartment's water supply. To turn off the water supply to the toilet, there must be a shut-off valve. Malfunctions with the toilet happen no less often than with the water supply, and most importantly, they do not coincide in time. In order to fix problems with the toilet, you need to shut off the line from the water supply.

If the water is drained from the tank, the float is in the bottom position of the tank, opening the path for water to enter through the inlet valve. As the liquid level in the tank rises, the float rises, gradually closing the inlet valve. Having reached a certain level of liquid in the tank, a pop-up float through a rocker arm connected to the valve membrane completely blocks the flow of water into the tank. At the same time, the pressure force of the liquid level presses the diaphragm release valve located on the drain rod to its seat. If the valves are in good working order, the drain system does not allow liquid to pass out of the tank.

To activate the flush, you need to pull the lever or press the release button on the tank. The release valve opens. Water rushes into the toilet bowl. The dual-mode tank has two release buttons: a small volume of working fluid for flushing and a full flush. Once the reservoir is empty, the inlet float is in the down position and opens the inlet valve. The system operation cycle repeats.

Assembly

To assemble and use a toilet with all devices, you need to follow the algorithm (using the example of the popular “compact” type with horizontal outlet):

• turn off the water to the old toilet;
• dismantle the old toilet and cistern;
• install the bowl and mark the mounting points if they do not match the old ones;
• drill holes and insert dowels into them;
• place the bowl in place, insert the fasteners and lightly secure them;
• check the level of the installed bowl;

• install the toilet lid and seat;
• carry out the work of connecting the outlet pipe of the bowl to the sewer pipe using a sealing collar, while treating the ends of the connections with sealant;
• seal the joint between the bowl and the floor and finally tighten its fasteners;
• install the tank (usually all elements of the tank are already ready);
• lubricate the sealing ring of the tank hole to the toilet mounting shelf with sealant and install the container in its place of fastening;

• tighten the bolts connecting the tank to the toilet and install the lid on the tank;
• connect a flexible hose from the water supply to the container;
• check the operation of toilet devices;
• In case of malfunctions, all systems must be adjusted and the problems eliminated.

If everything is in order, then you can start using the device.

Causes and troubleshooting

The most common problems are leaks through the drain system from the tank.

Remedies depend on the cause.

• The adjustment of the float of the water inlet system into the tank is broken and therefore excess water flows through the overflow. You need to open the tank and, by bending the float lever, achieve the desired adjustment of the water level in the tank. Tucking the float changes the water level.
• The seal of the seat or bulb on the tank drain is broken, so they do not hold the required fluid level. Plaque may be deposited on the pear and saddle, and they may also become deformed. The bulb and seat gasket should be cleaned or replaced.

• Water does not fill into the tank. If the intake valve is clean, then the possible causes are in the supply pipe, hose or tap. You can disconnect the hose and check the water pressure in the system. If the cause is confirmed in the supply connections, the hose, water supply filter or faucet must be cleaned or replaced.
• The inlet valve leaks after the level is raised. Sometimes it's all about incorrect level adjustment, as a result of which the float rests on the tank lid. You can adjust the level (reduce it) by bending the brass float lever.
• It is leaking at the water inlet into the tank. The level below the inlet hole should be adjusted and the rubber gaskets on this hole should be replaced.
• The water drain button (lever) does not work due to mechanical reasons or displacement of the flushing mechanism parts. Parts can be replaced and adjusted if necessary.

No matter how high-quality the toilet and fittings are, problems arise from time to time: either water does not fill, or, on the contrary, it constantly flows from the drain. All these problems are associated with fittings (drain and inlet valves), which are placed in the drain tank. Next, we’ll talk about how to install, change, adjust and repair it yourself, with your own hands.

Internal organization

The toilet cistern consists of two simple systems: collecting water and draining it. To troubleshoot possible problems, you need to understand how everything works and works. First, let's look at what parts the old-style toilet cistern consists of. Their system is more understandable and visual, and the operation of more modern devices will be clear by analogy.

The internal fittings of this type of tank are very simple. The water supply system is an inlet valve with a float mechanism. The drain system is a lever and a bulb with a drain valve inside. There is also an overflow tube - it drains excess water from the tank, bypassing the drain hole.

The main thing in this design is the correct operation of the water supply system. A more detailed diagram of its device is shown in the figure below. The inlet valve is connected to the float using a curved lever. This lever presses on the piston, which opens/closes the water supply.

When filling the tank, the float is in the lower position. Its lever does not press on the piston and it is pressed out by water pressure, opening the outlet to the pipe. The water is gradually filling up. As the water level rises, the float rises. Gradually it presses the piston, cutting off the water supply.

The system is simple and effective; the filling level of the tank can be changed by bending the lever slightly. The disadvantage of this system is the noticeable noise when filling.

Now let's look at how draining water in a tank works. In the version shown in the figure above, the drain hole is blocked by the drain valve bulb. There is a chain attached to the bulb, which is connected to the drain lever. We press the lever, lift the bulb, the water drains into the hole. When the level drops, the float moves down, opening the water supply. This is how this type of cistern works.

Modern models with lever flush

There is less noise when filling toilet tanks with bottom water supply. This is a more modern version of the device described above. Here the tap/inlet valve is hidden inside the tank - in a tube (in the photo there is a gray tube to which the float is connected).

Drain tank device with water supply from below

The operating mechanism is the same - the float is lowered - the valve is open, water flows. The tank filled, the float rose, and the valve shut off the water. The drainage system remained almost unchanged in this version. The same valve that rises when you press the lever. The water overflow system has hardly changed either. This is also a tube, but it goes into the same drain.

You can clearly see the operation of the drain tank of such a system in the video.

With button

Models of toilet tanks with a button have similar water inlet fittings (some with side water supply, some from the bottom). Their drain fittings are of a different type.

The system shown in the photo is most often found in domestically produced toilets. It is inexpensive and reliable. The design of imported units is different. They basically have a bottom water supply and another drain and overflow device (pictured below).

There are different such systems:

• with one button
  • water is drained while the button is pressed;
  • draining starts when pressed, stops when pressed again;
• with two buttons that release different amounts of water.

The working mechanism here is slightly different, although the principle remains the same. In this fitting, when you press the button, the glass rises, blocking the drain. The stand remains motionless. In short, this is all the difference. The drain is adjusted using a rotary nut or a special lever.

Installation and replacement of cistern fittings

A significant part of toilet problems can be solved by adjusting or replacing the tank fittings. In any case, you need to know how to disassemble and assemble the insides of the tank. This skill will definitely come in handy. When replacing, you first need to dismantle the old device and then install the new one. We will describe in detail the entire process, including the installation of new fittings.

How to remove the cap from the tank

If a flush tank with a button is being repaired, it is not always immediately clear how to remove the lid. This is easy to do: press the button and turn the ring.

If you can’t press the button with your fingers, examine its inner rim. There are two special slots there. You can take a screwdriver with a narrow end and use it to turn the ring a little. Then you can unscrew it with your fingers.

After this, remove the button by pulling it up. That's it, the lid can be lifted.

Removing the tank

To replace the old cistern fittings, it must be removed from the toilet bowl. First of all, turn off the water supply, then drain the water from the tank. Then, using wrenches, remove the water supply hose (it is attached to the side or bottom).

Next, you need to disconnect the tank from the toilet bowl. If you look underneath it, you can see bolts that are tightened with nuts. So we unscrew them using a set of open-end wrenches or an adjustable wrench. Before doing this, place a container or a rag near the toilet - a certain amount of water always remains in the tank, and when you unscrew the nuts, it will drain.

After unscrewing two nuts - on the right and on the left, we remove the tank. There is usually a gasket left on the bowl. If it has become deformed or dried out, it is also advisable to replace it.

Place the tank on a flat surface. There is a large plastic nut at the bottom. It holds the drain mechanism, we unscrew it. Sometimes the first turns have to be made using an adjustable wrench, but do not over-tighten it - the plastic can be brittle.

Now the water drainage mechanism can be easily removed.

Similarly, remove the water supply mechanism. With bottom feed, the fastening nut is also located at the bottom (right or left of center).

After that, we look inside the drain tank. Usually, rusty sediment, small metal particles, sand, etc. accumulate at the bottom. All this must be removed and, if possible, washed. The inside must be clean - any debris caught under the gaskets can cause a leak. After this, we begin the installation of new fittings.

Installation of cistern fittings

Everything happens in reverse order. First, we install a new drain mechanism stand. We unscrew the plastic nut from it and put a rubber gasket on the pipe. It can be white (as in the photo) or black.

Place the device inside the container and screw the plastic nut on the outside. We twist it as far as possible with our fingers, then tighten it a little with a wrench. You can't overtighten it - it will burst.

Sealing

Now on the toilet bowl we replace the o-ring that seals its connection with the flush cistern. Dirt and rust often accumulate in this place - we wipe it off first, the seat should be dry and clean.

We install mounting bolts inside the tank, not forgetting to put gaskets. We put the drain tank in place until it can be leveled. The main thing is to get the screws and the outlet part into the seats. Take a washer and nut and screw them onto the screws.

When both nuts are installed, but not yet tightened, level the container. Then, using a wrench, we begin to tighten the fastening. We turn it a few turns, first from the right, then from the left.

Install the exhaust valve

Lastly, install the inlet valve for the drain tank. It could have been installed earlier, but then it would be inconvenient to install the mounting bolts - there is too little space. We also put a gasket on the outlet pipe, then install it inside and secure it with a nut.

The next step is to connect water to the same pipe. Before connecting the flexible water hose, open the water for a while, giving the opportunity to remove scale, which accumulates every time after closing the tap, even for a short time. After draining a certain amount of water (place a bucket so as not to wet the floor), connect the hose to the fitting (turn off the water again).

Although the fitting is metal, there is no need to tighten this connection too much - first with your fingers, then one turn with a wrench. If you notice drops when you turn on the water, you can tighten it another half turn. After this, we check whether the system is working correctly. If everything is correct, install the cover and screw the button. You can test it again. This completes the installation of the drain tank fittings. As you can see, everything can be done with your own hands.

Adjustment and repair

When using the toilet, problems periodically arise - sometimes it flows, sometimes, on the contrary, water does not fill into it. Sometimes, tired of the inconvenience, people buy new toilets. But in vain. Most faults are resolved in 10-20 minutes. Moreover, everything is so simple that anyone can do it. You don't have to call a plumber. You can do everything yourself.

Adjusting the water level

We will talk about devices with bottom water supply. After installation, the toilet cistern must be adjusted. By default, they come from the factory set to the maximum amount of water in the container. This amount is often excessive. With the help of simple adjustments we can reduce the volume of water in the tank. For this:

The same procedure is necessary if water is constantly leaking from the tank. One of the reasons is that the float is raised too high. Because of this, water flows through the overflow system.

With a side water supply and a float mechanism, adjustment is even simpler - we change the position of the float by bending its lever. On the one hand it is simpler, but on the other hand it is more difficult. You have to bend it many times to achieve the required level.

Toilet tank is leaking

If the water in the toilet constantly leaks and its level is normal, we move on. There are several reasons for this leak. And if so, then the methods of elimination will be different.

• The rubber seal under the drain valve in the tank has silted up, dirt has gotten under it, and a groove (or several) has appeared on its surface. The method of treatment is to clean the existing gasket or replace it with a new one. To resuscitate the old one you need:
  • turn off the water, flush it,
  • remove the drain mechanism by unscrewing the plastic nut from below;
  • pull out the drain valve, remove and examine the gasket, clean it of settled particles, if necessary (there are grooves), sand it with very fine sandpaper until smooth;
  • install it in place, connect everything and check operation.

Water does not fill

Another problem that you can fix yourself is that water does not fill into the drain tank. Most likely the problem is a blockage - the filter or tubes are clogged. It's a long story, better watch the video.

23-05-2013: Vladimir

Thanks for the valuable information! The inlet valve on the SA2000S valve failed after three years of perfect operation. According to your recommendation, the cause was eliminated - hole 6 was clogged. I cleaned it with a thin copper wire, the intake mechanism works perfectly. Congratulations to Doctor Lom!

28-06-2013: Porter

Thank you for the article. They helped a lot. The video was especially helpful. When disassembling the fittings, the membrane fell out and therefore the water did not shut off. I couldn’t understand what was going on, and after watching your video, I started searching for the membrane and, having found it, everything fell into place. Great site.

23-07-2013: Igorek

And I have the following situation: there is a membrane valve (Pskov), but the bulb (old) slightly lets water through in a microstream (if the tank is not filled to the top and the bulb is not loaded). And then the water gradually runs away to a level where the valve float sinks and it begins to take in water. But the thing is that it does not open completely normally. And it jerks back and forth, it opens and closes the water, and there is a knocking and vibration in the pipe: thumping, thumping, thumping. And so he can drive for hours without stopping. I think this is not the case - the hose may be damaged in theory. It’s not clear what to do. Even if you install an old intake valve - which is a rod valve, not a diaphragm valve - at least it won’t “tug” the hoses and pipes if the bulb leaks slightly. What do you think?

23-07-2013: Igorek

Plus I forgot to add. When water is drawn in and the valve is open, water leaks out over the “cap nut” - which is in the freeze frame of the video. Is this normal or shouldn't it be like this? And secondly, if you take a rod valve (not a diaphragm valve), is it better to have a plastic fitting or a metal one?

23-07-2013: Doctor Lom

In your case, it is really better to install a rod valve. I prefer metal ones.
When the diaphragm valve is open, water can enter the tank not only through the main hole; this is not critical if the valve operates and shuts off the water. But this can also happen if the nut is not screwed on tightly.

25-07-2013: Valentine

Thanks for the description with pictures. I have a different float design. But it's not that. For me, an amateur plumber, the drawings are not very clear and the description is not very clear, there are still questions. It’s not clear why a rod “with a hole threaded through the hole in the membrane” is needed? The figure does not show the “filling chamber formed by piston 4 and membrane 3”. it is not clear what the diameter of holes 1 and 2 is. It is also not clear how it can all work if, in the end, water enters through holes 1 and 0.5 mm - judging by the sediment on the walls of the tank, these holes should clog very quickly. why don't they clog? “When the float is lowered, the hole (6) with a diameter of about 0.5 mm in the piston (4) is open, through it part of the water flows into the tank” - and how does the other part of the water get into the tank? “...or the membrane (3) or the rubber seal of the rod has deteriorated. All this can be washed and cleaned...” - if you clean the “deteriorated” membrane, will it be fixed? My valve stopped completely shutting off the water, I took it all apart and cleaned it three times, but I still haven’t figured out why the water doesn’t shut off. Usually the problem is in the rubber gasket (membrane), but it appears to be elastic and without damage.

25-07-2013: Doctor Lom

I'll try to at least partially satisfy your curiosity.
The lack of visibility of the drawings should be compensated by the video, where you can, in particular, see how a filling chamber is formed during the assembly of the reinforcement. The rod is necessary to redistribute the pressure generated in the storage chamber. If there is no rod, then the rubber membrane will not be pressed tightly against the end of the preliminary chamber, and therefore will not ensure the tightness of the joint.
The diameter of the holes depends on the design of the shut-off valves and, as already mentioned, is the result of a complex hydraulic calculation.
The holes can become clogged with solid particles contained in the water, but not silt, because the flow rate of liquid with a small hole diameter is very high (the laws of hydraulics - nothing can be done). This means that a turbulent flow is formed in the area of ​​water outflow, preventing the settling of particles suspended in the water. In addition, the relatively quick closing of the hole by the float rod leads to a sharp decrease in the flow rate of the liquid, which causes a water hammer (you probably noticed that the valve operates with a characteristic sound and even the fittings sometimes twitch). For example, a clogged filter at the inlet to the fitting means a decrease in the inlet diameter, and therefore a decrease in the pressure of the water supplied to the fitting. As a result, the water cannot reach the speed required for water hammer and the valve does not operate as required.
The main part of the water enters the tank through the preliminary chamber, this chamber is sealed when the valve is activated.
Flushing or cleaning helps if solid particles get into the holes or between the membrane and the piston. If the elastic characteristics of the membrane change during operation, the valve will no longer operate correctly and then it only needs to be replaced.
And yet, nowhere in the article is it said that fittings with diaphragm valves are a simple and reliable system that can be easily repaired. As a rule, inlet fittings with a diaphragm valve are replaced every 3-5 years.

25-07-2013: Anatoly

I have Ceresit fittings and the following problem: sometimes the tank fills up very slowly, water flows only from hole 6, that is, the membrane is not squeezed out, although the pressure is not very small. Moreover, the design itself is such that the rod only blocks this hole and does not move anywhere else, and chamber 2 is locked automatically by a membrane, there is no piston.
Will it help me if I increase the answer? 6?
And are there 3/8 rod mechanisms? I have such an outlet on the tank.

25-07-2013: Valentine

Thanks for the detailed explanations. but you confused me again. Please clarify what a “storage chamber” is? - you haven’t come across such a term. redistribution of pressure between what and what? how can the rod (i.e. the rod, as I understand it) redistribute the pressure? By the way, what is this rod attached to? Is it not just inserted into the membrane? why without it “the rubber membrane will not be pressed tightly against the end of the preliminary chamber”? does the rod fix the membrane and, perhaps, prevent it from deforming? (by the way, I have this membrane that is somehow thin and shaped, that is, it is not flat and, in my opinion, there is no chamber between it and the piston; I couldn’t even pull it off the valve). "...the water cannot reach the speed required for water hammer and the valve does not operate as required..." - i.e. Should there always be water hammer for proper operation? but why? it's unclear.
and about low pressure: you write that with low water pressure it will not flow into the tank at all, and at the same time the float will rise, but will not be able to shut off the water. This somehow doesn’t fit with me: so how will the float rise if the water doesn’t flow into the tank, and what should it then shut off if the water doesn’t flow?
and yet, you write that the diameter of holes 5 and 6 (you indicated their size) “..is the result of a complex hydraulic calculation...” and immediately propose to drill them out by eye. (by the way, I asked about the diameter of holes 1 and 2)

25-07-2013: Valentine

Anatoly, try unscrewing the cap a little (a quarter turn), perhaps it is pinching the membrane (it’s strange that you don’t have a piston, maybe you didn’t notice it?)

25-07-2013: Doctor Lom

Anatoly,

In the figures, the distance from the membrane to the preliminary chamber is shown larger for clarity. The actual movement is measured in fractions of a millimeter, so no special movement is needed.
Probably Cersanite, Ceresit seems to only deal with different kinds of mixtures.
If without fittings the water pressure is normal, and the slowdown in water intake does not always occur, then either the float does not lower completely due to interference in the tank or the design of the float is not successful (this happens), or when assembling the fittings the union nut is clamped too tightly, which sometimes prevents the normal collection of water, since the distance between the membrane and the preliminary chamber is less than required or the fittings are simply not of very high quality and should be replaced.
Increasing the diameter of hole 6 can lead to a decrease in flow speed and, as a result, incorrect operation of the valve. You should rather enlarge holes 1 or 2. However, there are now many designs of diaphragm valves.
If you mean a 3/8 inlet fitting with a rod valve, like in Soviet toilets, then I have never seen one.

25-07-2013: Doctor Lom

Valentin,

I made a reservation - the filling chamber.
By rod I mean the round plastic plate on which the membrane is placed. The plate is not shown in the figures, since it is located inside the filling chamber; the principle of operation of the plate is the same as the rod. The plate seems to cover the preliminary chamber, and the membrane acts as a rubber gasket ensuring tightness. You called this plate a valve, which is not entirely correct.
If the pressure in the water supply network is low, then the pressure in the filling chamber is low and is not enough to press the membrane tightly. The diameter of the inlet hole (1) is usually several times larger than the diameters of holes (5) and (6). Therefore, the lower the pressure at the entry point - hole (1), the greater the pressure difference in the preliminary and filling chambers
Water hammer is not necessary if the pressure in the filling chamber is sufficient, but as a rule, the operation of the diaphragm valve is accompanied by water hammer; moreover, upon impact, the membrane tightly closes the preliminary chamber while the float rod continues to move.
I wrote that “at VERY low pressure,” i.e. at such a pressure when the pressure is not enough even to overcome the local resistance of small-diameter holes. But low pressure and very low pressure are still different things. Inlet fittings with a membrane valve are usually equipped with a filter at the water inlet, and this is an additional local resistance that water cannot overcome at very low pressure.

25-07-2013: Valentine

Thank you for your answer, but every answer you give gives me new questions.
in fact, I always thought that a rod is a rod, usually used to connect two parts, but not a plate, which I call a valve, so I doubted it and decided to clarify what you meant.
further: “If the pressure in the water supply network is low, then the pressure in the filling chamber is low and is not enough to press the membrane tightly.” - as I understand it, it is not the pressure in the filling chamber that presses the membrane (99.99%) (what volume is this chamber, if it is so important for shutting off the water? - well, a couple of milliliters - no more, the pressure in it should be = pressure in the preliminary chamber, although you write about the pressure difference (where does the difference come from, even if water does not enter there, but there is no air there?), and why should it press down, and not evenly in all directions?), and the rod, about which are you talking about phase 2, which is pressed by a lever with a float that rises with the water? therefore, why the water will not shut off, even if the pressure is VERY low, if water, as you write, still enters the tank and raises the float - it is still unclear.
however, perhaps I’m wrong, but it seems to me that in reality everything is much simpler - it’s all about the gasket (membrane), otherwise, given that the water pressure does not match in any apartment, a “complex hydraulic calculation” would have to be carried out for each tank.

25-07-2013: Doctor Lom

I’ll tell you right away that I can’t explain the laws of hydrodynamics to you on my fingers, and there’s no point in commenting on every single phrase taken out of context. For example, I mentioned the difference in pressure when I told you about the possible reasons for the valve not to operate, and I wrote about the approximate equality of pressure when I described the principle of operation of the valve. You put these two statements on the same page, causing you misunderstanding.
For reliable operation of the valve, the pressure in the water supply network must be at least 0.05 MPa, which is 0.5 atmospheres or 5 m of water column. Working pressure parameters are given in the data sheet for each product and may differ from those given in the article. The diaphragm valve can operate at much lower pressures, but even the current GOST does not require this. Nevertheless, the operating pressure limits are very wide, which makes it possible to install fittings with such valves in many apartments.
How, when the pressure drops below 0.01 MPa in the water supply network, the membrane valve stops not only working, but even simply holding water and the water, overflowing the tank, flows into the toilet bowl, sometimes with a noticeable flow (up to 3 liters per minute), I observed repeatedly, while the float raised by itself to the limit.
And also, if you write your own description of the operating principle of the diaphragm valve, then I will only welcome it. If you want, I’ll even post your description as a separate article. Since any opinion is valuable and I, just like you, can be wrong.

26-07-2013: Valentine

Sorry for the meticulousness, I didn’t mean to offend you, I just would like you to explain in a little more detail, because... this is important for full understanding.
If you haven’t noticed, I didn’t put two of YOUR statements about the sameness and difference in pressures on the same level (I understood that you attributed this to different cases) - it was purely my assumption (possibly incorrect) that the pressures should be in any case the same - and I wrote why I think so. in this case, I wanted you to indicate (if you know this and without going into an explanation of the laws of hydrodynamics) where the pressure is higher and where lower, and by how much. This remains unclear to me.
Therefore, the fact that, as you write, at temperatures below 0.01 MPa, the water overflows the tank, and the float is raised to the limit and its pressure is not enough for the valve to reliably close the inlet - for me it’s a paradox.
Why did I become interested in this topic at all - the valve stopped completely shutting off the water (though it has been standing for 8 years), in appearance (after cleaning the plaque) it looks like new, and there is a water hammer, and the membrane appears to be elastic and without damage, but it doesn’t work!

26-07-2013: Doctor Lom

I’m not offended, but I feel that for better mutual understanding we should add illustrations, perhaps formulas, to our dialogue, but this is impossible in the commentary format. If you want, register on the forum (link on the main page) and we will continue discussing the issue there.
In the meantime, I repeat, in order for the membrane to be pressed tightly against the walls of the preliminary chamber, the pressure from the filling chamber must be greater. This is achieved due to the fact that the pressure in the chambers is approximately the same, but additional pressure acts from the side of the filling chamber - the force that pushes the float out.
This is a statement of the condition in general terms and thus a mandatory, but not sufficient condition for the normal operation of the valve. Since with this formulation we are considering certain average pressures acting on the membrane from both sides, over the entire area of ​​the membrane. Meanwhile, the pressure value along the height or width of the membrane (diagrams should be given here) changes. The pressure value at a certain point of the membrane is influenced by many factors, including the elasticity of the membrane and the geometry of all parts. Therefore, under certain conditions, for example at a general low pressure, the local pressure from the preliminary chamber can be greater than the local pressure acting from the filling chamber.
Now let’s return to your situation, although we should have started the conversation with consideration of it. Your valve operates normally, but water continues to flow into the tank after the valve operates - did I understand correctly? or does the water continue to rise at the same speed?

26-07-2013: Valentine

Thanks again, more detailed drawings with diagrams would be nice, but now something is becoming clearer, so there’s no need to fool around, especially since I’m the only one who has general questions, and one of these days I’m going on vacation.
I’m saying that I became interested in this out of necessity, because... I’ve been tinkering with the float for the third evening, but due to the fact that the only element that I have doubts about the design (although it looks like new) - the membranes (or with the piston) - cannot be changed, I will have to change the entire intake system.
yes, you understood my case correctly: the valve is activated (water hammer), after which the water slowly continues to flow and after 5 minutes it rises by 2 cm and is already overflowing. Moreover, I experimented - I pressed the float lever with my hand, and removed the float and pressed my finger on the valve instead of the rod - the water did not shut off.

26-07-2013: Doctor Lom

If water continues to flow slowly after the valve is activated, then one of the chambers has depressurized. There could be many reasons, such as wear of the rubber on the float rod, as a result of which the hole (6) does not close completely, but you seem to have ruled out this possibility. Defects and microcracks, but usually a loose connection. A loose connection can occur not only as a result of silting, ingress of solid particles, but also due to invisible wear of parts or as a result of accumulated inelastic deformations. In such cases, a complete replacement of the inlet fittings is the optimal solution in terms of time and money.

11-08-2013: Arthur

I’ll add a little about the design of such valves. Based on their operating principle, they are also called co-pressure valves, while the “Soviet” ones are called back-pressure valves. The rod threaded into the membrane may not be connected to the float at all and may not have a full hole; instead, there is a recess that performs the drainage function. The valve is closed only by sealing the chamber adjacent to the outer side of the membrane; the membrane is pressed against the seat only by water pressure, without having a direct connection with the float system. The float in this embodiment serves only to block the tiny drainage hole that drains the chamber adjacent to the outer side of the membrane. This design option is used, for example, in the Russian fittings of the Pskov plant. By the way, surprisingly, I even managed to find spare membranes for it in the markets (!). The second common design feature of such valves is the use of a float chamber, when the float floats in a special cup equipped with a drain valve. When water is drawn, the drainage valve of the cup is closed, the tank is filled, the water level reaches the edges of the glass, fills it, and thus the float moves quickly upward and the valve operates more clearly, and the level in the tank is more stable. When the water level drops, the glass is emptied through a drain valve in its bottom.

11-08-2013: Doctor Lom

Valuable additions and clarifications. Thank you.
When writing the article, I did not focus on the details you indicated, but now the article will be more complete and, I hope, more understandable.

15-08-2013: orderly Petrovich

Eh, my dear, I deleted your Inquisition due to an oversight. Yes, the plumber is right, it’s necessary to change the inlet fittings, since it’s buggy, it won’t do any good.

10-11-2013: Alexander

Please tell me, last year the Ido Arabia toilet was replaced with original fittings or something like that. Now a problem has arisen - it does not take in water, this mostly happens at night. When you turn on the water in the bath, the toilet is activated and begins to fill with water. And so again until nightfall, everything repeats itself, it jammed, opened the tap in the bathroom, closed it - the toilet started working. Is the pressure changing?

10-11-2013: Doctor Lom

I encountered a similar problem when using pumps that increase the pressure in the water supply network and automatically turn on when the tap is opened. Such pumps do not respond to the inlet fittings of toilet bowls. Perhaps you have a similar situation.

10-11-2013: Alexander

An ordinary single-entrance 17-story house built in 1995. Do you suppose that such pumps are installed in such houses?

10-11-2013: Doctor Lom

Anything can happen.

17-12-2013: Valery

In the video, after disassembling the float valve, a black hole is visible between the four stops. Should a rod connected to the float protrude through it, or is it just a hole? On the diagram - yes, but in reality it is not visible.

17-12-2013: Doctor Lom

If you mean fittings with a bottom supply, then this hole is blocked on the reverse side by the float rod. There are different designs of valves; the diagram shows one of the options to explain the principle of operation. It's really difficult to show all the details in a video.

26-04-2014: Anatoly

The valve does not hold water, it slowly adds water to the edge of the drain pipe((((((I spent time reading the article.... in general, I found a check whether the valve is working or not... if you blow into the water supply tube and close the hole where the water exits into the tank and close using a lever to close the hole that is closed with a float, then air should not pass through. I have the bottom supply shown in the video and the membrane, in addition to its immediate function, acts as a gasket between the chambers. In general, the gasket did not work and there was no tightness of the chambers when the drainage holes and water supply to the tank were closed. I wound the tape around the edge of the membrane and pulled it tighter... it became better... I used to add 1 cm to the tank in 10 minutes now in half a day))))

26-04-2014: Anatoly

Closed for comments?

27-04-2014: orderly Petrovich

Everything is open.

27-04-2014: Anatoly

Apparently the comment goes through professional analysis)))))

27-04-2014: Doctor Lom

Since 90-95% of comments are added by bots, and usually in English, I introduced pre-moderation. I don’t think that users are very interested in sheets of generated almost meaningless text.

15-06-2014: Victor

I came across the same situation: the water in the drain tank rose to a level, the float rose and after five minutes the water overflowed. The cure was very simple - I cleaned the filter at the inlet of the float valve. This is one of the very first reasons and it’s a pity that this is not shown in the video, although this filter is even visible on one valve. Thank you very much to Dr. Lom, everything is written and everything is correct.

18-06-2014: Anton

Good afternoon. I have this situation. Low pressure in the central water supply of a private house. I installed a storage plastic tank. The pressure at night is normal, but it is not enough to push through the standard float valve; a trickle runs thinner than a match. Tell me which float valve can be installed.

18-06-2014: Doctor Lom

In such cases, it is better to use an inlet fitting with a rod valve rather than a diaphragm valve. These were used in old Soviet toilets and are still sold today.

22-06-2014: Alexei

Good day to all! Who can tell me? I installed a toilet in the dacha, water supply from below, diaphragm valve. Water is supplied from a 200 liter tank, the pressure to close the valve is low. How can I solve the problem, can someone tell me?

22-06-2014: Doctor Lom

It is possible to exchange fittings with a diaphragm valve for fittings with a rod valve. It also sometimes helps to install a pump that automatically turns on when the water opens.

07-10-2014: ZEOS

Very useful information. Thank you. I didn’t know there were holes there......today, instead of buying a new one, I’ll try to clean the old one.

07-10-2014: Vladimir

The almost instantaneous blocking of hole 2 by the membrane is explained by the presence of positive feedback, which sometimes causes a noticeable water hammer (shudder of the flexible line). The physics of the processes here is as follows: when the closure of hole 6 begins, the pressure above the membrane increases, which causes it to move towards hole 2. Partial closure of the hole. 2 (a decrease in the flow through it), due to the continuity of the flow of incoming water at the valve inlet, causes an increase in the flow of water into the filling chamber through the hole with the rod. The pressure above the membrane increases even more. The process becomes like an avalanche. As a result, the membrane simply sticks to hole 2 since there is practically no pressure behind hole 2, and above the membrane it is equal to the water pressure.

14-12-2014: Sergey

The valve stopped working, took it apart, it turned out that the membrane had burst, there is nothing like it on the market. I made a mold, but in my opinion the wall turned out to be a little thicker and the membrane does not work, now I’ll think about what to change.

07-03-2015: Ilya

Hello!
There was a strong whistle when filling the tank, I took it apart and found fishing line in the membrane, threw it away (I thought it was garbage). The whistling stopped for a while, but after 2 days it whistles again and the water overflows. I threw away the fishing line in vain. why does it whistle/buzz? Thank you in advance.

07-03-2015: Doctor Lom

The higher the pressure in the water supply network, the greater the likelihood of various noises appearing when filling the toilet tank. Sometimes the pressure can be adjusted using a valve on the supply pipe. However, if the valve does not hold water, then the fittings will most likely have to be changed; by the way, with strong pressure, the fittings fail faster.

13-05-2015: Denis

Hello!
similar problem: ROKA VICTORIA NORD toilet with GEBERIT fittings (bottom water supply, float in the chamber), fills the tank normally, closes normally, but with a small addition of water (water flows into the toilet in a thin stream), the valve opens with a specific whistle and after a few seconds When the tank is full, it closes again with a whistle. I have the 1st floor, the pressure in the system is very decent (I didn’t measure it). I tried throttling the inlet ball valve, but it didn’t help, it whistles even at very small opening angles until the valve is completely closed. I don’t know whether to try installing a control valve in front of the intake, maybe clean the valve and its inlet filter (I haven’t done this yet, everything is new). please advise what to do?

14-05-2015: Doctor Lom

If water flows in a thin stream into the toilet bowl, then you need to worry about repairing not the inlet, but the drain fittings. It is normal that when the water level decreases, the float drops and the inlet fittings start working. But the fact that the gasket of the drain fittings is poisoning - no. More details in the article “Water constantly flows into the toilet bowl, what should I do?”

08-06-2015: Ilya

Good day. I installed inlet fittings (with a membrane) for the side water supply (1st floor). The essence of the question is that water is being collected (already good :)), the float rises and the water is shut off, but it poisons the air in the area of ​​the membrane, and after a while the drops begin to siphon and then where the membrane is, water constantly flows from there. I tried to regulate the water supply with a tap, I tried to disassemble and clean the membrane, but the problem remains.

09-06-2015: Doctor Lom

Perhaps the fittings have a manufacturing defect and should be replaced with a new one.

10-06-2015: Fixed it)

Thank you!)

11-06-2015: Andrey

Good afternoon. I have a Jika Lyra toilet, they installed it today, the water supply tap rests against the wall, the water is supplied at half pressure. The tank is only half full. Could this be due to the water pressure or how is the valve regulated?

12-06-2015: Doctor Lom

Try adjusting the float.

13-09-2015: Lena

Hello, The lower supply valve was leaking water, I took it apart, cleaned it of rust, then it worked fine for a couple of months and then started leaking again, I decided to replace it, I bought it and there was a piece of fishing line sticking out of the hole in the membrane, this didn’t happen in the old valve, so I take it out or install it directly, why is it needed?

14-09-2015: Doctor Lom

In fact, you should contact the manufacturer with this question, because there are a lot of designs of fittings with a diaphragm valve. Perhaps this fishing line is needed for the project, so don’t touch it, but install the fittings and check its operation. If the fittings are not working, then it is better to return them.

14-09-2015: Lena

Thanks for the answer, I installed it as is, it works well, it only makes noise before it shuts off, so be it, we have low water pressure in the house, then it surges. If it breaks, I’ll buy another one, this one is cheap, 100 rubles.

15-09-2015: Tanya

Good afternoon. My membrane in the side valve has torn, now the valve is leaking, or rather splashing. Can I buy the membrane separately somewhere? Compact Сersanit, served for 11 years

15-09-2015: Doctor Lom

Unfortunately, the realities of the modern consumer era are such that it is now much easier and faster to buy a completely new intake valve than to look for a repair kit for a valve that was produced 11 years ago. However, you can look for information about repair kits on the manufacturer’s official website or contact the nearest authorized Cersanit service center.

25-09-2015: Eugene

Thank you. Everything is very detailed and accessible. Using this information, I was able to overcome the valve leak: I cleaned it, wound the stem to reduce the hole, and added a filter. The flight is normal.

01-10-2015: Tatyana Mikhailovna

Hello! I want to repair the intake valve myself. I read everything here, didn’t understand a lot, but bought a membrane unit on the market because... its original membrane was torn (the seller took it out of the assembled valve and sold it for 200 rubles, and the whole valve for 500 rubles). In general, I saved money, but when I assembled everything at home and put it in the tank, it turned out that the valve does not shut off the water when the float rises. I suspect that the new piston does not fit in size, although the brand is the same, Alkaplast. Am I thinking correctly and shouldn’t I go to the market again and buy the rest of the valve? Thank you.

01-10-2015: Doctor Lom

It is more correct to change the entire valve, because the problem may not only be in the valve itself, and the valve models, even from the same manufacturer, can be different. Therefore, it’s worth going to the market and buying the rest of the fittings, you’re thinking correctly.

04-10-2015: Tatyana Mikhailovna

Hello! You can now ask about the outlet valve; when pressed, the water from the tank is drained, but the valve does not return to its place and the water already flows directly into the toilet. If you press the overflow tube with your hand, the valve will close the flow of water into the toilet, but these are all actions with the open cover Question: is it possible to fix anything in this situation with your hands on the spot, other than changing the valve? Thank you.

04-10-2015: Doctor Lom

Tatyana Mikhailovna, please look at the article “The compact toilet is leaking, water is constantly flowing into the bowl, what to do.” In addition, the models of drain fittings are also different; sometimes it is possible to load the tube (attach some weight to it in a certain way), but this method is not very reliable.

04-10-2015: Novel

Hello! I have a problem with the toilet. Water slowly fills into the tank, within about 10 minutes. And in recent days, it also flows heavily into the toilet and the water sometimes doesn’t have time to fill at all. Help me solve the problem. Thanks in advance.

04-10-2015: Doctor Lom

As a rule, this happens when the filter on the inlet fittings becomes clogged or the pressure in the cold water supply system drops significantly. When the pressure is low, the valve stops working. Most often, cleaning the filters helps in such cases. But sometimes you have to change all the fittings.

27-10-2015: Mikha

Hello. There are 2 bathrooms in the apartment plus one at my mother’s house - a total of 3 toilets, all with membranes. Bottom supply, although this is hardly important. It’s not hard to guess that I often have to have fun with the replacement; I don’t do cleaning, because... After the very first incident, I realized that this was a poultice for the devil.
IMHO, after a few years of operation, the rubber of the membranes begins to “tan,” that is, lose elasticity, and, as far as I remember, every time the problem of “under-closing” of the next valve arises closer to winter, when the temperature of the tap water drops significantly. Perhaps the elasticity deteriorates very slightly, everything seems OK to the touch, but the ice water factor makes its contribution.
Unfortunately, I couldn’t find spare membranes in stores, so every time the solution is radical - a new intake unit. As a rule, I use Alcaplast (I haven’t come across any cooler/more expensive ones in our city). However, I even had the opportunity to use some Ketai nonname, which lasted for 5 years - bravo!

29-11-2015: Nikolay

Question! Assembled the toilet. The toilet is not connected yet! To check, I poured 2 liters of water into the tank. There are no leaks anywhere except that water flows out of the filling fittings (fitting) in a thin stream. The cone gasket prevents leakage from the tube itself. Should it be like this or should the unconnected water tank be sealed?

29-11-2015: Doctor Lom

Judging by the description, you have a toilet with a bottom water supply and in this case there is nothing surprising in the leakage of water. Firstly, the membrane valve operates only at the appropriate pressure, and secondly, this pressure will be provided by the water supply system.
It will be much more effective to check the operation of the toilet with the water connected.

02-06-2016: Gennady

Good evening! I have such a situation, after turning off the water, the valve stopped holding water, I washed everything, cleaned it, it still flows. What's the matter?

03-06-2016: Doctor Lom

Perhaps one of the filters was clogged, which led to a decrease in water pressure, or after assembly, not all parts were installed in the designed position.

03-06-2016: Gennady

All the parts are in place, I replaced the membrane, no effect. The pressure seems to be normal, but there is a suspicion that the filter is clogged. I’m going to buy a new inlet valve. Maybe put a coarse filter in front of the inlet, otherwise we have this now due to routine maintenance often?

03-06-2016: Doctor Lom

The filter will, of course, significantly reduce the likelihood of valve clogging.

10-08-2016: Basil

the explanation is not accurate, when the float is raised, the hole closes, and no rod presses on the membrane; when the tiny hole is closed, the pressure behind the membrane rises and the pressure of the membrane closes the hole (the valve itself) through which water is supplied to the storage tank.

24-08-2016: Sergey

The inlet valve is from Dolomit - is it possible to replace it with a valve from another company, since I didn’t get my own one?

24-08-2016: Doctor Lom

In principle, you can install fittings from any manufacturer, the main thing is that the diameter matches and there is enough space in the tank.

11-09-2016: Andrey

Today I spent half a day working on the toilet, dismantling and cleaning the fittings. I assembled it, but the inlet valve does not close when filling. I came across your article on the Internet, read it, it turned out to be simple - while cleaning, I lost the rubber seal in the “rocker arm”. I cut a new one out of the old gasket - everything works! Thanks a lot!

16-09-2016: Irina

Hello, dear Doctor Lom!
Thanks for the detailed description! Guided by him, several times it was possible to bring the intake membrane into working condition. Unfortunately, this time she simply physically falls apart. Question: In your video, which brand of intake diaphragm is shown? Do you know what other companies use exactly the same membrane? I have a Hybner, and finding an original membrane or a whole intake is unrealistic. And it looks absolutely exactly the same as shown in yours.
Thank you.

16-09-2016: Doctor Lom

The fact is that I shot the video about 5 years ago and now I won’t say what kind of fittings are shown there. One seems to be from a French toilet, the second from the nearest construction market.

16-09-2016: Irina

In your video, the membrane of interest is visible from approximately 0:48 to 1:08.

16-09-2016: Doctor Lom

But no, it looks like I was mistaken, it was the fittings for the Polish Cersanit toilet, but I don’t remember the exact model now.

20-09-2016: Valentina

Hello, at night the water pressure drops due to which water in the toilet begins to flow (Cersanit), although during the day everything is fine with normal pressure. Please tell me a complete description of how to change diaphragm fittings with a diaphragm valve to fittings with a rod valve.

20-09-2016: Doctor Lom

In principle, it is not difficult to change; it is much more difficult to buy high-quality fittings with a rod valve. See the article "How to disassemble a compact toilet."

22-09-2016: Inga,

Good afternoon, please tell me what is the solution to the following problem - water from the tank is drained into the toilet using a funnel along the walls of the bowl, forming a weak whirlpool. There is no quality of flush at all. The tank fills well and quickly.

23-09-2016: Doctor Lom

Perhaps this is the design of your toilet bowl or there are defects in this design, so the problem cannot be solved without replacing the bowl. However, you can raise the tank as much as possible to improve the quality of flushing, as was done before.

Whistling of the filling fittings with the tank of the lower connection: as a rule, when disassembling all the parts are in perfect order, but the whistling does not disappear, the following helped me: the filling fittings were completely disassembled, cleaned and reassembled to identify the “whistling” part, I decided not to put it back in place, but unscrewed the shower head and connected it to the hose (in most cases the thread is identical) turned on the cold water and realized that the whistle was coming from the silicone gasket with the stem, after a long dance with a tambourine nothing helped, it continued to whistle then I turned on the hot water (almost boiling water) and left it for 15 minutes in the bathroom, after which I immediately switched to cold (contrast shower), the whistle disappeared and after installation in place did not appear, I have already observed normal flight for 3 days :)

01-10-2016: Novel

Good evening! For the first time I encountered the replacement of a mechanism in a barrel, completely! It seems that everything was installed as in the instructions, but a problem happened... in general, when the water is supplied, it does not stop. As it turned out, the float does not lower or rise on its own due to water pressure, thereby not fixing the closing/opening of the water supply! Could you help me with anything? I bought the mechanism SA 2000, water supply from below. Feels like something is holding him

01-10-2016: Doctor Lom

From your description it is difficult to understand what exactly caused the problem. As a rule, the float is the most reliable part of the valve structure, but it may be warped, or it may be a factory defect. Try raising and lowering the float by hand; it should move freely within the required limits.

03-10-2016: Maksim

Good afternoon Please tell me about this case: I reinstalled the barrel (there were problems with water retention by the outlet valve, I removed the tank and valve, cleaned the outlet, put everything back in place) after that the flush changed, it began to swirl (like a tornado) and is now flushed 3-4 times . What could have changed after installing the tank?

04-10-2016: Doctor Lom

You may have a problem with your exhaust valve adjustment. Try raising it higher.

07-12-2016: Sergey

Hello, what should I do if there is damage to the membrane? Can I repair it or make it myself?

07-12-2016: Doctor Lom

As a rule, the membrane cannot be repaired, only replaced, but it is also quite difficult to find a repair kit for a certain type of intake valve. It’s easier and faster to buy new fittings. It is also unlikely that you can make a membrane at home; it is not just a rubber gasket in a fitting with a rod valve, which can simply be cut out of an old chamber.

13-12-2016: Eugene

Good afternoon, Doctor Lom! I have an IDO toilet. After disassembling and cleaning the inlet valve, the water pressure stopped stopping. Tell me, please, what could this be connected with? I disassembled and reassembled several times - it was impossible to restore functionality. Before the first disassembly everything worked well.

14-12-2016: Ivan

Place a check valve in front of the hose and that’s it, but it’s expensive, but it works.

14-12-2016: Doctor Lom

From your description it is difficult to determine a possible cause. It seems that you simply forgot to put the membrane in place, or installed it incorrectly, or it failed. However, other reasons are also possible, for example, loose assembly, etc.

17-12-2016: Alexei

Hello! I have the following problem! I have a similar inlet valve and everything works properly and does not let anything in, BUT after draining the water, water begins to flow through the inlet valve weakly and reluctantly, with an empty tank and after 5 - 7 seconds it shoots out and picks up vigorously and correctly! I dismantled all the fittings, all the valves - I cleaned everything and washed it of plaque, but unfortunately the situation has not changed! Where did I miss it? Thanks for the answer...?

17-12-2016: Doctor Lom

Perhaps this is just a factory defect in the fittings and it’s easier to change it than to look for the defect itself.

22-12-2016: Irina

Good afternoon After installing a new toilet, when the tank fills with water, vibration and noise from the tank occurs, and quite significant. Vibration does not occur with every fill of water, but 1-2 times a day, mainly in the evenings. The tank contains a set of filling fittings with a bottom water supply and single-level drain fittings SA2000/S Czech Republic. Please tell me what this could be and how to deal with this phenomenon?

22-12-2016: Doctor Lom

As a rule, in the evenings the pressure in the cold water system decreases slightly. Accordingly, the flow rate decreases when the tank is filled. But why in your case there is a resonance of oscillations - vibration, it’s difficult for me to judge. Perhaps a foreign object has entered the system, creating a local obstacle to the flow, or the design of the inlet fittings is such a local obstacle.
Simply put, you need to either ensure constant pressure in the water supply system, or flush the system, or change the fittings.

06-11-2017: Doctor Lom

And thank you, Evgeniy. And for the positive feedback and for the ten. It’s immediately obvious that a good person came to visit. And regarding the rod fittings, you are basically thinking correctly.

Nevertheless, miracles happen. Recently I helped a good person (it was a woman, and I’ve had a weakness for women since childhood). So she has had a fitting with a diaphragm valve in her toilet for 17 years. When I removed the lid, I thought 300 years had passed since the toilet was connected, everything was full of stalactites and stalagmites. We have chalk mountains in Mayaki, so there is a lot of calcium (or anything else, I’m not good at chemistry) in the water. But nothing, I cleaned off the build-up, pulled the float and everything works fine again.

So it goes...

16-11-2017: Kirill

Crap... The drawings are not at all clear. The explanations are absolutely cloudy, confusing and incomprehensible... I have an inlet valve - like the second one in the video. It matches your drawings only vaguely at best. I don't see a moving horizontal rod. I can’t understand why the overflow occurs (after cleaning the valve). I can’t identify which holes are on MY valve. I see the membrane. There are no micro holes. Night. Everything is broken. It is extremely difficult to read and understand.

17-11-2017: Doctor Lom

I sincerely sympathize with you, Kirill. I think you will find clearer and more understandable information on the website of the manufacturer of YOUR fittings. In the meantime, turn off the water supply and go to bed peacefully. And if anything happens, you can drain the water from the bucket.

08-08-2018: Michael

Hello. I have this problem: periodically (about 1 time out of 10) the outlet does not close after draining. GEBERIT fittings. Is it possible to adjust it somehow?

08-08-2018: Doctor Lom

It's hard for me to judge from here. Try calling a plumber.

20-10-2018: IN

Thanks a lot! I bought an Alcaplast inlet valve, but it pours water once, and after the float comes up once, after that it no longer works. It turned out that there was a microscopic grain of sand in hole 6 - I hadn’t seen it in your picture yet and couldn’t think that there was a tiny hole there and the whole operation of this plastic piece of garbage depended on it. Cleaned it - it works. Apparently until the next grain of sand.

11-07-2019: Igor

I struggled for a long time and finally came up with the idea of ​​sticking tape around the piston (4 in the picture). After years, the piston did not fit tightly and water began to leak around the edges. Now everything works perfectly.

11-07-2019: Doctor Lom

Igor, thanks for the good advice. I think it will definitely be useful to some of the readers.

12-07-2019: Igor

Still, I was in a hurry about ideality. In a few hours a liter was filled. This did not affect the water meter in any way, but I still decided to buy a new mechanism. At first I thought of buying only a piston with a membrane and a rubber band, but these spare parts cost 50 UAH, and a new set cost 90. So if the mechanism is 5 years old and you don’t mind 90 UAH, better change it and don’t suffer. I mean the case when neither rearranging the elastic band helps (there is also a way to cut it in half and turn the halves over), nor cleaning everything. If the membrane wears out and the plastic wears off, there is nothing you can do to help.

Inlet fittings with a diaphragm valve (for toilets

Inlet fittings with a membrane valve (for compact toilets)

The inlet (fill) fittings in toilet tanks vary. Modern compact toilets usually use fittings with a membrane valve - this is clearly not the idea of ​​a Soviet engineer. The design solutions of engineers of the Soviet school were always distinguished by their simplicity, which increased the reliability of the system, and in the event of failure, the ability to eliminate the problem using available means. And this applies not only to toilets, but also to spacecraft, the design of which Americans still admire to this day. In Soviet toilets, whether with a cast iron tank, or with a plastic one, or even in compact toilets, inlet fittings of the simplest design with a rod float valve were installed. Water is drawn into tanks equipped with such fittings slowly, unevenly and noisily, sometimes very noisily: with howling, grinding and rattling. But almost any adult man could adjust the fittings of a Soviet toilet, and even my mother-in-law liked to tinker with the cistern without waiting for expert advice.

The filling fittings of modern compact toilets with a membrane float valve are a completely different matter. Water draws in quickly, although not always quietly; everything here depends on the quality of the fittings; it shuts off immediately. But filling fittings with a diaphragm valve also have disadvantages. These disadvantages are connected with the fact that for the normal functioning of the fittings it is necessary that in the water supply network there be a more or less constant pressure of at least 0.05-0.1 MPa (0.5-1 atmosphere) and no more than 1-2 MPa, and in addition to pressure, membrane valves need pure water. It is clear that it is not always possible to fulfill both of these conditions in private houses, villages, and holiday villages. In addition, the reliability of operation of membrane fittings is also influenced by the quality of workmanship and the quality of materials used to manufacture the fittings. Therefore, fittings with a membrane valve have to be repaired every few years, but more often they can simply be replaced, like a used razor; you cannot cut a new membrane from an old tire for such fittings. We'll have to figure out what kind of fittings this is and how it works.

For owners of Jika toilets, as well as toilets equipped with Slovenian-made inlet fittings, I can offer the following diagrams for installing inlet fittings with a diaphragm valve:

Well, for everyone else, I present the following, in my opinion, a more visual model of the operation of inlet fittings with a diaphragm valve. But first it’s better to look at the membrane and see what it is. After watching the video, it will be a little easier to understand what we are talking about:

Phase 1. The valve is in the open position, water is drawn into the tank.

The membrane moves away under the pressure of water and does not interfere with water accumulation (it does not interfere so much that it is not even shown in the diagram yet). Water enters hole (1) and fills the preliminary chamber. In order for water to enter the toilet cistern, there is a hole (2) in the preliminary chamber; this is where the water passes. For this moment, everything is very similar to a regular stem valve, but here the valve is a diaphragm valve, which means that the valve has a membrane (3) placed on a piston (4):

There is a hole in the membrane through which a rod with a hole (5) with a diameter of about 1 mm is passed, the exact diameter of the hole is the result of scrupulous calculations, which is why a plastic rod is used. Through this hole, part of the water passes into the filling chamber formed by the piston (4) and the membrane (3). When the float is lowered, the hole (6) with a diameter of about 0.5 mm in the piston (4) is open, through which part of the water flows into the tank. Thus, the water pressure in the preliminary chamber, in the filling chamber and behind the filling chamber is approximately the same, and this is the main difference between the operating principle of a diaphragm valve and the operating principle of a simple rod valve.

Phase 2. Water entering the tank raises the float.

When the toilet tank is filled with water, the float rises and pushes the rod with the rubber seal towards the hole (6), the hole closes. The rod, moving further, presses the piston (4) with the membrane (3) to the large seat, while the filling chamber becomes sealed, and to the small seat, indicated in orange for clarity in the figure. The water pressure in the filling chamber plus the pressure from the rising float presses the membrane tightly against the seats, and the collection of water stops. I didn’t draw how the rising float pushes the rod, I hope it’s clear, and you can always look at it, just remove the tank lid.

Repairing built-in toilets or installation is more difficult due to incomplete accessibility to the installation mechanisms.

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How to change the diaphragm valve.

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Details at http://doctorlom.com/item99

Not that there is a great need for this, in 90% of cases it is much faster and more efficient to completely change the float membrane fittings like a cartridge in a printer, especially if the water supply is from the side. But I can’t refuse those who want to tinker with the fittings.

The quality of the toilet directly depends on the serviceability of the shut-off valves responsible for the supply and drainage of water. Currently, you can see many different models of this plumbing equipment on sale. There are not many types of shut-off valves, since they are of the same type and are suitable for various modifications. Let's take a closer look at how toilet shut-off valves work.

Types of shut-off valves and their features

Shut-off valves can have a separate or combined design. In the past, toilets used exclusively a split configuration. In it, the filler and drain valves are installed separately and function autonomously. The operation of the filler valve is regulated by a float, which, when water rises in the tank, shuts off its supply by means of a control rod. The drain assembly consists of a neck with a valve, which can be:

• air;
• mechanical.

Control is performed by operating a button, pedal, key, lever. The advantages of separate shut-off valves include the ability to replace or repair only the damaged unit. This saves costs simplifies installation and dismantling. Therefore, such systems are still used in toilets today.

Elite class products and the latest models use a new design of shut-off valves. In it, the drain and fill valves are connected into a common system and have direct traction dependence. Adjusting prefabricated shut-off valves is difficult. But with precise tuning, safe and flawless operation of the unit is guaranteed. The disadvantages of such a system are the need for complete dismantling in case of breakdown and the complexity of repair work.

It also differs in the material of manufacture. In most cases, polymers are used for it. The strength and durability of the fittings and the flawless operation of the system depend on the composition of the plastic. Previously, the cost of reinforcement could be used to judge the quality of the material and the accuracy of the design. Currently, the number of manufacturers of these products has increased significantly. New companies that are just beginning to conquer the market are releasing quality products at low cost. And, on the contrary, counterfeits are sometimes found in certified goods. Therefore, unfortunately, low-quality fittings can only be identified during operation.

High strength and long service life metal fittings. Bronze or brass alloys are used for its manufacture. These materials are highly resistant to moisture and mechanical stress. Therefore, they retain their functional qualities for several years and are not destroyed by corrosion. Toilet manufacturers install a single shut-off valve metal fittings only in elite models made in a certain style. Any toilet can be equipped with separate systems.

Upper and lower shut-off valves for toilet

Shut-off valves are divided according to the installation location and method of water supply. It depends on which side of the tank, top or bottom it is built in. system design, which is taken into account if it is necessary to replace a damaged unit.

The main difference in configuration and installation is the shut-off valves for the upper and lower water supply. In both systems, the valve is closed by the action of a control rod connected to a float, which can be plastic container or foam part. When installing the fittings, it is carefully balanced. This is necessary for the efficient operation of the system, which depends on the correct water level in the cistern.

Domestic toilets are equipped with fittings that provide top water supply. This system is located on the side of the tank. The disadvantage of this design is noise, which is created by the system when water is supplied. Many foreign manufacturers equip toilets with lower shut-off valves. These designs operate silently, which increases comfort and provides more stylish look of the model. Installation of the upper system is carried out after installing the toilet cistern, the lower fittings must be equipped before it is placed on the toilet structure.

Operation of the toilet cistern flush mechanism

The drain valve design is much simpler than the water supply unit. It does not have a locking mechanism, as this design does not need one. The drain valve is controlled using a rod. She may look like chains or rods.

In former times, it was widely used in the construction of toilets. lever arm located on the side or top of the tank. Now most models are equipped with a more convenient option - button. This mechanism can provide two modes of water drainage. Depending on the degree of pressing the button, the tank is completely emptied or half of its contents are removed.

When you press a lever or button, it opens damper, closing the upper fitting, and water pours into the toilet. After this, the weight of the damper forces it to return to its original position, and the drain valve closes.

The process of installing toilet shut-off valves

You can purchase shut-off valves separately, but it is easier to install branded systems that come with the toilet. In this case, an exact match of all elements is guaranteed.

In progress on installing the tank you will need:

First, it is necessary to install the base of the drain unit in the tank, ensuring tight fit it to the outlet. A rubber gasket is placed between the base and bottom of the tank. The tank is then installed on the toilet. Between them you need to install a thick rubber ring, which will prevent the surfaces from touching. The tank is screwed to the toilet using bolts.

If the model has a bottom water supply, before installing the tank you need install water supply fittings. In this design, it is important to securely secure the rubber gaskets to prevent leakage. Such parts are not required in the upper fittings, since they are located above the surface of the water. Such units can be installed after installing the tank. The installation method is the same for both types. The tube is inserted into the hole in the tank and tightened with nuts at both sides.

At the next stage, a flexible hose is connected to the fitting of the water supply riser, a water tap is installed, which will allow, if repairs are necessary, to shut off the access of water to the toilet. Modern hoses are equipped nut-spacer clamps, ensuring connection reliability. But plumbers usually play it safe by using fuma. After connecting the tank to the water supply, you need to adjust the float. The water level should be approximately 15 cm below the edge of the tank.

In the final stage of installation, it is equipped water drain mechanism. The upper structural element is inserted into the hole in the lid and secured with decorative parts that cover the hole.

Malfunctions in the operation of the drain tank

The main malfunctions of the drain tank are associated with violations in the installation of shut-off valves or wear of its elements. If it is necessary to replace valves or dismantle the tank, it is necessary to close the access to water. If there is a tap at the outlet of the water pipe, simply close it. Otherwise, you need to close the riser.

The designs of shut-off valves for toilets are not complicated. Knowing the features of their device makes it possible choose the right model plumbing equipment, do-it-yourself installation and repair. This will save money and eliminate the need to call specialists.

Video instructions for installing toilet fittings