Non-return safety valve for water heater. Check valve for a water heater: a detailed description of why a check valve is needed

Water heaters are installed not only in private houses that are not connected to the central water supply, but also in city apartments. The possibility of self-regulation of temperature and a comfortable existence during the period of scheduled repairs - these are the advantages of apartments and houses with boilers. Self-installation of such complex equipment requires strict adherence to all connection rules and safety precautions. Since the electric power in the water heater is combined practically with boiling water, a safety valve is necessary.

Peculiarities

The safety valve for the water heater helps prevent overpressure from building up inside the appliance. When the liquid is heated to certain temperatures, the device must turn off the heating at the signal of the thermostat, but in rare cases the sensor may not work or simply break. The design of the boiler assumes tightness and closed taps, therefore, when the water overheats and steam forms, which occupies a larger volume, an explosion may occur. The safety valve allows, in this case, to relieve the pressure to the standard values ​​of 10 bar and normalize the operation of the entire system.

The functionality of the safety valve is not limited to this alone. It also prevents the water heater from flowing back into the supply system when it is empty. Any fuse consists of a body, a stem with a handle at the top, a spring and a plug. Both ends of the body have pipe threads ranging from 1⁄2" to 3⁄4" depending on product.

Kinds

There are practically no special differences between the many types of safety fittings for a water heater.

Most often they are divided into three groups depending on the volume of the heating apparatus.

1. Valves for boilers up to 50 liters. This category includes standard disposable valves. They are almost always non-separable and their service life is very short. But their cheapness allows, without any difficulties, to simply change such devices once a year.
2. Valves for boilers up to 200 liters. More serious devices that professionals recommend installing even on boilers up to 50 liters. They consist of several valves for various purposes and an additional nozzle for sewage supply.
3. Valves for boilers with a volume of more than 200 liters. These are serious devices of complex configuration, including a pressure reducing valve and a device for draining water and various adapters. Most often, such valves are installed on large industrial heaters and are rarely installed even in large private houses.

In addition, safety valves may differ in the presence and operation of additional structural elements. For example - trigger handles.

Using such a handle, the operation of the valve is checked as follows:

1. The lever is installed vertically.
2. It pulls on a spring.
3. The spring opens the current to the water.

Such a check should be carried out at least once every couple of months. With the help of the trigger lever, the water from the tank is also completely drained. Until the water runs out completely, the handle must be held until it drains completely.

For some models of protective valves, such a lever can be fixed with a special screw, which prevents spontaneous opening when the spring is weakened. There are also valves without a relief design for forced drainage of water. Most often they have a lid mounted on a thread. Through it, the valve can be cleaned of scale and blockages.

The high quality of the purchased product is indicated by the marking applied to it. For example, an arrow should be engraved or drawn on the body to indicate the direction of fluid flow. Also on the body must be applied information about the maximum allowable pressure that the valve can withstand. Even professionals will not be able to distinguish between a four and six bar valve if there is no information about this in the accompanying documentation. Of course, such a device will have a higher cost, but the priority should still be the quality of the entire system, and not its price.

In addition to the above, differences may be in the shape and length of the fluid outlet fitting. A long non-linear fitting without an extension at the end will be more convenient, since it is easier to put a hose on it and secure it with a clamp. In addition, sometimes, instead of a safety valve, a subversive one is installed on a home boiler. It is designed to quickly remove water in an emergency and should not be bled multiple times. Although the functionality of these constipations is largely similar, one cannot replace the other.

Boiler safety fittings are often referred to as a check valve, but they are actually a completely different device, although they look similar in appearance. The check valve is responsible for the unidirectional flow of water, and the safety valve protects the pipe and the water heater from destruction under excessive pressure. Installing a reverse locking device instead of a safety locking device can cause damage to property and health of residents. A unidirectional water flow device will not be able to stop the heating of the liquid above the boiling point in the event of a thermostat failure and will not prevent an explosion inside the device, which will destroy not only the boiler, but also the walls of the room.

Principle of operation

Standard water heater fuses consist of three independent valves:

• the safety valve itself (in rare cases, subversive);
• check valve;
• drain (drain) valve.

The safety valve includes a metal stem, a plug at its end, a powerful spring and a fluid drain fitting. As soon as the pressure inside the boiler exceeds the value indicated in the documents, the device is triggered, the rod will compress a tight spring and it will open access to water to the fitting, through which it will flow out. This happens so smoothly that the flow of water is just a large number of drops.

The check valve includes a plastic stem with a rubber plug at the end and a weak spring. Unlike plumbing, the boiler check valve is not designed to hold high pressure water and serves as an ordinary damper, which is why the spring is so weak. It just prevents water from flowing into the pipes in case of an emergency or turning off the water in the central water supply.

The last but very important valve is the bleed valve. It consists of a check valve stem and a small spring. He works "on the safety net" of the safety. When the pressure approaches critical values, but does not cross them, the drain valve is able to normalize the pressure inside the heater while turning on the water tap or draining the toilet. When the water in the pipeline slightly lowers its pressure due to this, the drain valve opens and the excess of almost boiling water goes back into the pipe.

Installation

Before installing safety fittings on an installed water heater, it is necessary to study the offer of the construction market and choose a quality product.

Good valves have several distinguishing features.

• The body of a good unit is made of brass alloy by seamless casting. Sometimes it is plated with nickel to prevent corrosion and scale formation. Unlike cheap copper or aluminum alloys, brass is heavier and therefore easy to distinguish.
• When you press on the stem of high-quality shut-off valves, you can see how the plug walks tightly inside the body. Even its slight jamming at the end is allowed.
• A bad valve can be identified by simply blowing into it. If even with a strong pressure on the rod, the air freely escapes, then it is better not to take the product. At the same time, if water periodically drips from the fitting of the installed constipation, this does not mean that it is broken. Perhaps you just need to clean the plug from sediment and everything will work again.

If you follow these tips, you can choose the right fuse the first time and start installing it right away. There are few requirements for it. The valve is always installed in the cold water line. It is placed between the constipation valve and the pipe inlet to the boiler body. You can cut it directly into the water supply pipe or install a special tee at a distance of no more than 200 cm from the heater inlet.

In addition to the fuse, nothing should stand in this area. Most models are installed in such a way that water enters them vertically from below. An arrow showing this movement should be marked on the fuse case.

A PVC pipe is attached to the fuse fitting, connecting it to the sewer pipe. It is better if this tube is transparent - you can see if the device is working properly.

The installation process itself is divided into several stages.

• Disconnecting the installed boiler from the mains and draining the water from the tank. You need to make sure that the water supply to all pipes is shut off, otherwise, at the time of cutting the required section, you can simply flood all the apartments below.
• The valve body is purged with air to remove stray debris and dust. A tow or FUM tape is being prepared, which will serve to waterproof the threaded connection.

• With a wrench, the valve is screwed in at the junction of the pipe and the boiler. The arrow on the valve body must match the direction of fluid flow. The union nuts must be well tightened, the joint can be additionally coated with silicone sealant.
• Before connecting the boiler to the mains, it is worth crimping the connection with cold water. If, after 5 minutes of fluid flow, no drops appear at the junction, then everything is connected correctly.

The safety and check valves are also checked “cold”. In the first case, you need to press the trigger flag weakly at first (the first drops of water should appear), and then at full strength. When fully pressed, water should quickly flow through the transparent outlet tube. The non-return valve can be checked by filling the water heater tank completely and shutting off the central water inlet. When you open a faucet in the bathroom or in the kitchen, the flow of water should quickly stop. If water continues to flow from the faucet for several minutes, then the check valve needs to be adjusted.

Sometimes individual elements of the water heater or the entire system stops working properly. This reduces the safety of the structure and can lead to sad consequences. In this case, you need to find out the cause and place of the breakdown as soon as possible and either fix it yourself or call a specialist for this. Most often, thermostats, heating elements and safety valves fail. Moreover, a problem in the work of one of them can instantly affect the rest. You should never install elements that do not match the parameters of the boiler or have different connection methods.

Problems cannot occur on their own, they have certain causes.

Most often they are as follows.

• Untimely replacement of damaged parts. For example, the check valve should be changed at least once a year. It's cheap and doesn't cost much.
• Incorrect installation of the entire system. If the fuse insert in the pipe is made with insufficient waterproofing or too far from the boiler inlet, the system will not work properly.
• Voltage fluctuations in the mains can lead to failure of the heating elements of the system.

• The presence of a factory marriage or lack of preventive examinations. In order to choose the right heater and fuses, you need to carefully study all the information when buying. And even the highest quality device needs to be checked periodically.
• Scale formation or corrosion. Scale and corrosion on the non-return valve can cause water to leak back into the pipeline or corrode various connections, violating their tightness.

The most basic malfunctions can be divided into several types. Most often, the broiler starts to flow. This can be either a manufacturing defect or a crack acquired due to corrosion. Such a tank cannot be repaired on its own, it will have to be completely replaced. Water dripping from pipe joints indicates a leak. From the safety valve, water, on the contrary, should sometimes drip. If it is always dry, then it should be replaced.

Self-installation of a boiler is considered a responsible event that requires maximum compliance with the rules and regulations for connection. A safety group is necessarily involved in the piping of the water heater, which includes a safety valve for the boiler - a small but functionally important device.

In this article, we will consider the types of safety valves, their design features. After all, in order to install the heater without errors, you should understand the device and the principle of operation of the valve.

And also we will give instructions for tying the boiler and tips on installing a safety valve, we will give useful recommendations on choosing the right equipment.

Relief valves are often confused with check valves, and sometimes the term "check" is simply applied to them. In fact, these are two completely different devices, although they have common features.

The check valve is responsible for ensuring the movement of the medium inside the pipeline in only one direction, while the purpose of the safety valve is to protect the pipe and the units connected to it from destruction caused by an increase in pressure in the network above the norm.

The replacement of concepts occurs, since the second important function of the fuse is to create a barrier that prevents the fluid from moving in the opposite direction.

Industrial-type mechanisms differ from simpler and more compact devices used in everyday life. It looks like a spring valve installed on a production pipeline

There are several types of locking mechanisms that protect complex technical devices from pressure surges. Among them are spring, magnetic-spring, lever, lever-load devices.

The choice of one or another type is explained by the purpose of the pipeline and the characteristics of the medium that moves through it: water, oil, hot steam, aggressive chemical solutions.

For the installation of an electric boiler, one type of valve is intended - spring. They may differ in appearance, but their internal content looks the same.

Design and principle of operation of the device

To begin with, we will analyze in detail the device and the principle of operation of the safety valve.

Safety valve device

The safety valve, like other types of fittings, has a simple design and is a combination of two spring mechanisms enclosed in a common metal case.

There is no fundamental difference between brass and steel products, but brass is a little more expensive and, according to reviews, lasts longer. The springs inside the case are made of chrome-plated steel.

If there is a sharp increase in pressure above normal in the line, then the spring works and opens the hole for the ejection of fluid. The outer end of the cylinder is covered with a plug, screw or lever device.

The appearance of the safety valve with a plastic lever: 2 - thread for tapping into the cold water network, 3 - thread for connecting to the boiler, 8 - mini-pipe for liquid outlet, 9 - lever for forced opening

The yellow marker in the figure circles the area on which the marking is embossed. It indicates the maximum pressure rating at which the valve operates. The pressure is indicated in MPa, but it is easy to convert to atmospheres: 0.7 MPa = 7 atm.

Also on the body is an arrow indicating the direction in which water moves from the cold water system to the heating tank.

Image gallery

A safety valve for a water heater, boiler or a check valve device is one of the main elements responsible for the safe operation of the device in conditions of pressure drops when heating water.

Purpose

In the process of heating water in the storage tank of water heating equipment, the volume of liquid increases by about 2-3%. In accordance with the law of thermodynamics, even with a slight increase in temperature, a closed system is characterized by an increase in pressure.

The temperature control devices and thermostats installed in the boilers make it easy and effective to control the temperature regime of the liquid, but if they fail, the pressure increase inside the system becomes critical.

Safety valve for Ariston water heaters

The result of an avalanche-like increase in the pressure level is a rupture of the boiler body and an explosion of water-heating equipment.

In order to prevent exceeding the permissible pressure limits, a safety valve is installed that is capable of dumping part of the liquid to the outside in a critical situation.

However, the functional purpose of the water pressure relief valve for the water heater in water heating equipment is not limited solely to the protection of the boiler, but is also presented:

• preventing the return of heated liquid from the storage tank to the plumbing system;
• smoothing water pressure surges or the so-called water hammer at the inlet to water heating equipment;
• discharge of an excess amount of heated water from the tank in conditions of a critical increase in temperature and pressure levels;
• the ability to drain the liquid from the water-heating tank in order to carry out preventive maintenance and repair measures.

The absence of a valve does not prevent the outflow of heated water from the boiler in an emergency, so exposed heating elements burn out in a short time.

The safety valve will prevent backflow of water into the conduit, prevent pressure surges and water hammer, and also allow excess liquid to be drained for maintenance purposes.

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Principle of operation

The safety valve is represented by the main body structure and several elements, which are located in a brass or nickel shell. As a rule, this device has an inverted T-shape. A non-return valve is fixed at the bottom of the water heating tank, which prevents water from flowing out under the influence of a drop in the pressure level in the pipeline.

A valve device is located on the perpendicular branch, which operates when the pressure rises, and is also responsible for draining excess fluid through the fitting. A correctly installed device works in stages.

Check valve in the circuit

When the pressure level in the reservoir is lower than that in the pipeline, the filling process causes the poppet plate in the valve to be squeezed out under the influence of water pressure.

The normalization of pressure is accompanied by the closure of the plate and the limitation of the flow of water into the system. The active heating mode is characterized by a slow increase in the temperature of the water and an increase in pressure, which can reach maximum values. In this case, the defense mechanism is activated.

Periodic draining of liquid through the choke channel should not cause concern, as it indicates the functioning of the safety valve of the hot water boiler in normal mode.

Varieties

The safety valve device installed on domestic hot water equipment is most often represented by three main groups:

1. Protective devices for water heaters with a volume of not more than 50 liters. in the form of disposable valves. A feature is the presence of a non-separable design, low cost and a fairly short service life. However, some very well-known manufacturers of boilers are equipped with valves of higher quality characteristics.
2. Devices for water heaters with a volume of not more than 200 liters, characterized by a 7 bar safety valve, a check valve and a shut-off ball valve, as well as a special nozzle for connecting to the sewer system.
3. The safety device for water heating equipment with a volume of more than 200 liters is represented by mandatory elements in the form of a pressure reducer, a tap, a non-return and safety valve with a drain fitting.

Completely disassembled safety valves are equipped with special test points that facilitate diagnostics and maintenance of water heating equipment.

Many American manufacturers, as a rule, install closed-type valve devices on their water-heating equipment with no visual control of operation.

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Choice

Most often, all modern water heaters are implemented with an already installed protection system in the form of a safety valve with certain parameters. When purchasing the device yourself, you should pay close attention to the features of the threaded part, as well as the maximum operating pressure.

Installed valve

Each valve is designed for a certain level of pressure, which must be indicated in the technical passport of the equipment. The total volume of the tank must also be taken into account. Produced protective systems can have a response threshold from 6 to 10 bar.

If the safety valve is incorrectly selected or installed incorrectly, there may be a constant leakage of liquid or a very strong overheating of the water heating equipment.

Installation

Self-installation of the device, as a rule, does not cause difficulties. Before proceeding with the installation, it is necessary to disconnect the water-heating equipment from the electrical network and drain all the water from the tank, and then carry out the installation, adhering to the following simple recommendations:

• the safety element is installed at the cold water inlet to the boiler;
• during installation, it is necessary to use a FUM sealing tape or traditional tow;
• the second side of the fuse is connected to the cold water supply system;
• in the presence of pressure drops in the water supply system, a reducer is installed in front of the valve.

Valve Installation Diagram

A flexible and transparent hose is used to connect the drainage pipe to the sewer system. It should be noted that sometimes a special safety valve is replaced by a demolition device designed to discharge liquid in emergency mode.

Despite the similarity of functions, the principle of operation of such devices is noticeably different, so you should not rely on the correct operation of such a device.

It is forbidden to mount locking devices in the area from the entrance to the water heating equipment to the safety valve, and also to remove the protective element more than two meters from the boiler tank.

Possible breakdowns and causes

There are some of the most common problems that can occur during the operation of the safety safety valve of water heating equipment:

• When the boiler is disconnected from the network and the water supply is turned on, liquid flows out of the drain hole. The reason is a breakdown of the safety element or an increased level of pressure in the plumbing system.
• When the boiler is connected to the network, there is a minimum water intake, prolonged heating of the water and a constant flow of fluid from the drainage hole. The reason is a malfunction of the safety valve.

All failures associated with a safety valve are usually accompanied by frequent water leakage or a complete lack of fluid flow. In both cases, it is advisable to replace the device with a serviceable protective valve set to similar operating pressures.

It is very important to connect a flexible and transparent hose to the drain outlet of the device, which allows you to easily visually monitor the performance of the safety valve installed on the water heating equipment.

The correct operation of the safety valve installed on the water heating equipment is a guarantee of the safety of property and your own safety, therefore, when choosing and purchasing such a device, you must make sure that it fully complies with the operating parameters and rated power, as well as organize competent installation in the system.

Related video

To determine what exactly a safety valve for a water heater is for, it is initially worth remembering some rules from physics. Namely, everyone knows that when water begins to heat up, it increases in volume. If you heat it to 80 ° C, then it will increase in volume by 2 - 3%, depending on what temperature the water was before heating.

Due to the fact that the container in which the water is heated in the boiler is completely sealed, strong heating increases the pressure inside it. If the pressure is not adjusted, an explosion may eventually occur. In this case, a safety valve comes to the rescue, relieving a certain amount of pressure.

In other words, check valve:

• Prevents the penetration of water back into the water pipe;
• Helps to normalize the pressure inside the device;
• Provides the ability to drain water if the device requires maintenance.

It is essential to install it, as it is important that it should be reliable.

Check valve for water heater

If you carefully examine the water discharge valve and what it is for, you can see that this is a whole system of valves, in particular two.

Namely:

1. The first is responsible for relieving excess pressure. The safety valve is connected to a hole located on the side of the housing.
2. The second valve is located at the bottom near the inlet. It is due to him that cold water does not flow out of the device if there is no pressure in the water supply.

Until the moment when there is less water inside the tank than in the water supply, it squeezes the plate in the check valve and enters the tank. As soon as the pressure becomes the same, the spring begins to press on the plate in the housing seat, which prevents the flow of additional volume of liquid.

Subsequent actions to activate and block the valve are carried out on demand.

Inside the boiler, a gradual expansion of the liquid occurs when heated. After the permissible hot water pressure limit is exceeded, the spring in the safety valve is compressed.

Next, the plate exits the socket, the hole opens and excess liquid drains. As soon as the optimum level of pressure is reached, the plate returns to its place in its original position.

Considering the device and how the mechanism works, we can conclude that the fuse is required for emergency release of pressure so as not to spoil the equipment and not face an emergency.

Water pressure relief valve: how to choose

The drain valve in each type of boiler is individual, and it is included in the kit from the manufacturer.

Each valve features:

• parameters;
• connectors;
• Installation method and location.

If you need to replace the valve, you must first familiarize yourself with the technology of the work and, if necessary, it is better to contact a specialist in plumbing equipment. On average, the pipe thread in apartment and private houses on water pipes is ½ inch, and therefore the product is selected according to the working pressure.

The pressure value is indicated in the instructions for each water heater.

If the level of the protective device is designed for high pressure, then during the installation of the device there may be an emergency up to a rupture of the tank, pipe, and more. If the part is installed with less pressure than in the device, the valve will constantly leak.

When buying a boiler, be sure to check the presence of a safety valve, as well as make sure that it is in good working order and fits perfectly to the designated place.

The passport of the water heater contains information about which way the valves should be turned when checking. When purchasing the valve separately, you must consult the seller so as not to endanger yourself or the device. During the operation of the water heater, it is imperative to check the valve and all equipment for faults.

Relief valve adjustment

Installing a valve on a water heating tank requires careful work and maximum concentration. It is at the time of installation that a kind of valve adjustment is carried out, in which there is a spring mechanism. Regulation is carried out by a special handle, which does not need to be selected, because it is included in the kit. Namely, such a part as an adjusting cap is rotated, compressing a steel spring, and thus the load is moving along the lever.

Important! If the heating system functions stably and without interruptions, and if the pressure is not exceeded, then the relief or safety valve does not work for a long time.

This contributes to clogging of the valve and, accordingly, its contamination.

To avoid this, you need:

• Regularly inspect the valve;
• Turn on the valve and carry out a special maneuver;
• A kind of cleansing.

This is how you can avoid damage to the product, because it may be required at any time, and in the event of a malfunction, serious consequences are possible, up to the breakdown of the product.

It is strongly not recommended to use a two-position valve in the heating system. This is understandable, since when a critical pressure level is reached, the device automatically opens, which reduces the level as quickly as possible, just like the subsequent closing of the valve. All this becomes the cause of a water hammer, which leads to a rupture of the requirements and the tank itself.

Installing a safety valve on a water heater

The principle of operation of an indirect or protective valve is quite simple, because it has two cylinders. The large cylinder is the so-called non-return valve, which has a special flap or poppet valve. It is he who is driven by a small spring.

Both ends of the cylinder have special threaded parts, through which the product is connected to the desired connectors.

The small cylinder is mounted vertically relative to the large one. The ends are sealed with special plugs, and it is equipped with a drain tube, as well as a built-in small valve. There are certain types of valves installed on the boiler.

They may differ in key parameters, for example, in the method of installation.:

• Irreversible.
• Foster.
• Steel.
• Ball.

Depending on the principle of operation of the water heater, there are different types of non-return valve: direct, indirect, designed for two positions and proportional.

There are also types of non-return valves, which have different heights of constipation.:

• Full lift.
• Medium lift.
• low-lift.

The purchase of a safety valve should be carried out in specialized stores and preferably taking an old part with you. In the absence of such a part, you should rely on the technical characteristics of the water heater model. It is worth noting that by providing work on the installation or maintenance of fuses to the master, you can thereby protect yourself from serious consequences.

In particular:

• Breakdowns;
• pipe rupture;
• Tank explosion.

Specialists use not only the necessary devices, but also provide a guarantee for the actions taken. In other words, trusting the work to a specialist, you don’t have to worry about the fact that the life of the equipment may be reduced or the valve will not fulfill its assigned task.

What is a safety valve for (video)

It is strictly forbidden to start the boiler without proper installation of valves and without a preliminary check of the quality of the installation, which is carried out through a test run of the equipment. If there are no leaks or air leakage, the device can be operated without fear. The subversive defense mechanism must be in good working order.

An electric water heater creates comfort in the house by providing residents with hot water. But those who often come across him know that the boiler can pose a certain danger associated with a rupture of the container if it is installed incorrectly. A properly assembled circuit, including the mandatory installation of a safety assembly, will help to avoid this.

To understand why a safety valve on a water heater is needed, we must remember the lessons of physics. Water heated to a temperature of 90 ° C expands by about 3%. It is easy to calculate that inside a 50-liter boiler, during operation, the volume of hot water will increase by 1.5 liters. If it is not drained, the container will simply break. To prevent this from happening, a valve is installed that is designed for a certain pressure. When a critical point is reached, the mechanism is triggered, bleeding excess fluid into the sewer.

That's what such a mechanism is for. Its device protects the boiler from excess pressure that occurs when water is heated.

Principle of operation

If we take a closer look at the device of the valve and the principle of its operation, then the whole mechanism can be called a valve system. This is because there are two of them in one building. The work of the first is clear, excess pressure is bled from the boiler through it. The mechanism is connected to the side opening of the case. What is the second check valve for? The arrangement of the mechanism inside the housing is such that the check valve is located at the bottom opposite the inlet. It prevents cold water from flowing out of the boiler in the absence of pressure inside the water supply.

The principle of operation of the mechanism is as follows:

1. As long as the pressure inside the water heater is less than the water pressure, water squeezes the check valve plate, constantly flowing into the tank. After the pressure is equalized, the spring presses the plate against the seat of the body, thereby preventing the flow of liquid into the tank.
2. Further work of the mechanism consists of waiting. The liquid inside the boiler gradually expands from heating, and until the pressure reaches a critical point, the valve system is closed.
3. After exceeding the allowable limit, the hot water pressure compresses the safety valve spring. The plate comes out of the housing socket, opening a hole where excess fluid will drain. Having reached normal limits, the spring presses the plate back to the seat, setting the mechanism to its original state.

Having considered the device and the principle of operation of the mechanism, we can conclude why water often drips at the outlet. This will always happen when the temperature of the liquid rises and the water pressure drops, which indicates the normal operation of the device.

Then the question arises, what to do with the liquid flowing from the side hole. A PVC pipe is connected to the outlet to drain the water. It must be reinforced and fixed with a clamp to the nozzle. These performance requirements are mandatory, as the operating pressure, which is in the range of 6-10 bar, will tear and burst the tube. Sometimes they ask the question, why make a drain from a transparent tube? The answer is simple, for convenience. Through transparent walls it is convenient to control work. That is, it will be seen whether water is flowing or dripping, which can often indicate a malfunction of the mechanism.

Existing types of valves

The conventional non-return valve for a water heater is produced in different designs. Although the appearance and principle of operation are almost the same, there are still some nuances.

Each modification of the design helps to comfortably use the boiler, and sometimes, on the contrary, interferes:

• a safety valve with a lever is convenient for a control check of the mechanism for operability, which must be carried out monthly. Raising the flag, the lever forcibly opens the drain hole. It also helps to drain the water heater completely in case of an emergency. Some models have flags fixed with a screw. It protects the mechanism from accidental opening;
• When installing or replacing a valve, attention must be paid to the presence of a direction arrow and marking of the permissible working pressure. In the absence of such, the direction of movement of the liquid can be recognized by the location of the plate in the socket, looking inside the housing. But how to find out the working pressure, because it is only tested by checks? No way, and the sellers will not help in this either. Therefore, it is better not to install such models;
• the fittings themselves, through which water is discharged, may also have their differences. It is convenient to put on a tube on a long herringbone-shaped ledge and fix it with a clamp. The short fitting also has a thickening on the edge to hold the hose, but there is not enough room for a clamp. The tube will have to be crimped with wire;

• if the safety valve is not equipped with a flag, it is intended for forced draining only. It is impossible to check its performance with a control drain. It is good if the case has a threaded cap for maintenance. By unscrewing it, you can clean the clogged mechanism. There are cheap maintenance-free models. Such valves should generally be abandoned because of the danger of their use.

The considered types of valves are usually used on a boiler with a capacity of up to 60 liters. In a large water heater, the valve goes together with a pressure gauge and a stopcock. The fitting is threaded, which makes the fastening of the drain hose reliable.

Installation rules

In order for the boiler to work safely, it is necessary to correctly install the check valve in the system. Usually it comes with a water heater. If not available, the safety device must be selected separately, and the allowable pressure of the valve must correspond to the working pressure of the boiler. All parameters can be found in the product manual.

Installation of the safety assembly on the boiler can be carried out with and without adapters, but subject to certain rules:

The device of some valve models may differ in the presence of a pressure mechanism actuation regulator. The principle of its adjustment is to loosen or tighten the clamping spring. You need to know that initially the mechanism has already been adjusted by the manufacturer, and it is impossible to make your own changes there without experience.

After installation, water is drawn inside the water heater to check all connections. If there is a leak, you can try to tighten the thread. Otherwise, you will have to drain the water to repack the compounds. You can check the operation of the valve by turning the flag. If, during this action, water flows from the fitting, and after the flag returns to its original position, the flow stops, then the mechanism is working properly.

Possible breakdowns and a method for their elimination

Breakage of the safety unit is expressed by the constant flow of water or its complete absence. If the liquid flows or drips only when heated, which is convenient to observe through a transparent tube, then everything is working properly. That's what this node is for.

Let's look at the possible causes of the leak:

• sometimes water drips from a cold boiler. Here you can observe the drop frequency. If it becomes more frequent and then subsides, it is possible that the water pressure exceeds the permissible limits. The non-return valve is constantly open and excess water pressure, passing through the water heater, is released. After the normalization of the water pressure, the flow will stop. With frequent repetition of such situations, it is advisable to install a reducer at the inlet of the water supply to the house;
• sometimes water drips due to debris under the plate seat. You can correct the situation by periodically bleeding off the liquid using the emergency lever. The flowing water will wash away the dirt, the plate will sit tightly in the saddle, and the dripping will stop before the boiler heats up. When bleeding did not give positive results, a spring is pulled out from the collapsible model to clean it from dirt. If this does not help or the body of the safety assembly is not separable, it will only have to be replaced with a new one;
• usually leaking water brings additional costs, but there is no danger of the water heater bursting. It is bad if the liquid does not flow at all and does not drip. This may be due to scale in the mechanism itself or inside the fitting. Only mechanical cleaning will help here or it is better to change the assembly;
• some valve models may leak due to improper installation. They need to be wound only four turns, otherwise the adjustment is pressed through. Improved models with a limiter are now being sold, which can be screwed all the way. It is best for an inexperienced person to give preference to just such a design;
• situations happen that a person sins on a valve, and the boiler itself is to blame. This is due to the rapid increase in pressure at the outlet of the water heater when it is heated. The first reason occurs when the thermostat breaks down, which can be replaced with a new one. The second reason is the worst. Cheap Chinese products inside the tank have little room for liquid expansion. This can be corrected by installing a hydraulic accumulator or purchasing a high-quality boiler.

The operability of the safety unit will protect the residents of the house from burns that can be obtained during the rupture of the boiler with boiling water. The main thing to remember is that a simple check valve cannot be installed instead of such a node. This will only make the situation worse.

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