In some cases, air accumulates in the heating system. For open systems(with expansion tanks open type) this is not a problem - it comes out on its own, and for closed systems it is necessary to remove it. As there are fewer and fewer open systems - they are considered less stable - air exhaust devices have become an integral part of modern heating. Today there are both automatic and manual models. There are different designs, connecting dimensions, made from different materials. But they have one function - to remove gases from the heating system.
In normally designed systems, air rarely appears. Mainly after filling or refilling. If the layout is not entirely successful, suction occurs constantly. What are the dangers of its high content in the system? The most unpleasant moment is that in this case corrosion is activated, the metal components of the system quickly rust and fail. Second problem: increased level noise And third, air jams form. Therefore, automatic air vents are installed in each system at the highest point.
This is a radiator automatic air vent. It is only slightly larger than the Mayevsky faucet, costs about $2, but it removes gases on its own
Most often, gases accumulate at the tops of radiators. Then the coolant circulation in it deteriorates. And this leads to the fact that the battery is only partially heated (which part remains cold depends on the type of connection). Therefore, manual air vents are installed in each heating device (radiator, register or heated towel rail). In our country, the Mayevsky crane is most often installed.
Why do they put manual models on radiators? They occupy less space and are cheaper. But there are modern special modifications automatic devices, which are only slightly larger in size. They cost more (the device is more complicated), but the air is removed on its own.
Where are radiator air vents installed? In the pipe-free upper radiator manifold.
On which radiators should gas vents be installed?
Installation on aluminum batteries is required. When aluminum comes into contact with the coolant, water decomposes into components, one of which is hydrogen. Therefore, it is necessary to vent gases in such heating devices.
It is advisable to install it partially. In them, the contact area of aluminum with the coolant is greatly reduced, but is still present. That is why the installation of the Mayevsky crane is desirable.
This is a straight and angular automatic air vent. They can also be placed on radiators, only the “pimply” should look up
Fully bimetallic radiators safer in this regard: their entire core is made of steel. But many manufacturers require such a device in their installation recommendations.
These devices are ineffective on . In them, air removal is possible only with sufficient a large number coolant. But these devices (both manual and automatic) are not suitable for this. In this case, standard or ball valves.
With tubular radiators and registers, the situation is approximately the same as for cast iron: only taps work effectively. Therefore, there is no point in installing air vents on them.
This is a needle air vent valve, or a Mayevsky valve.
Installation of Mayevsky taps on steel panel radiators is mandatory. The fact is that the passages for coolant circulation have a small diameter. And if an air lock forms, the movement of the coolant will be blocked. It will completely or partially stop heating. You can remove the plug only by draining most of the coolant and filling it again. Therefore, most often panel radiators come straight from the factory with air bleed valves.
Types and technical characteristics
Depending on the method of removal, these devices are of two types:
- manual;
- automatic.
They are made with different diameters. The most common are 1/2” and 3/4” (half an inch and three quarters of an inch). In nature, there are also 1/8”, 1/4” and 3/8”, but they are not used in our systems. The modification most often used is a half-inch diameter 1/2”; in another system of units it is also called DN 15. In this case, the number 15 is the designation of the connection size in millimeters.
In addition to diameters, the following parameters are also important:
- Working pressure. In most models it is 10 atm, there are devices designed to operate at 16 atm.
- Type of work environment. There are air valves, and there are those that handle liquids. Heating systems use working liquids or universal ones (both air and liquid).
- Temperature of the working environment. More often they are found with an operating temperature of 100 o C - 110 o C. There are those operating up to 150 o C.
- Thread type: external or internal.
These technical characteristics of air vents must be selected according to existing type systems. For individual systems any heating system is suitable, but when selecting devices for radiators powered from centralized systems, you need to know both the pressure and the temperature specifically for your home (find out at the housing department, housing department, housing office, etc.).
Operating principle of automatic air vent
The designs of these devices may change, but the principle of operation remains the same. The device is a hollow cylinder, which consists of two parts - upper and lower. They are connected to each other using a thread, the tightness is ensured by a rubber (silicone) sealing ring. There is a small hollow protrusion at the top cylindrical. Air leaves the system through this protrusion. It has a thread onto which a plastic (polypropylene) cap is screwed. With this cap, you can stop bleeding air if desired (tighten it).
One of the devices is simple and effective
Automatic operation air valve based on the buoyancy of a float placed inside. The float is connected to a rod that acts on a spring-loaded spool that closes the outlet. If there is no air in the system, the air vent housing is filled with coolant, the float has risen up. In this position, the rod supports the spool, and air does not come out (or come in). When air appears in the system, the coolant is gradually displaced and the float moves down. The rod does not press as hard on the spool, and the spring opens the outlet hole. The accumulated gas escapes, coolant is again drawn into the housing, and the valve closes.
In devices different companies The mechanism of action on the spool can be different, but the principle is unchanged: the float is down, the valve is closed, it has risen and it is open. The operating principle of one of the modifications is demonstrated in the video.
Types of automatic air vents and their installation
These valves can be straight or angled, and there are special models for radiators. Specialized or angular modifications are often installed on batteries. They are screwed into the radiator manifold (if the diameter allows) or installed through an adapter.
Regardless of the type, the device must be installed so that the outlet (cap) is directed upward. There are two installation methods:
The shut-off valve has a spring-loaded gasket inside, which, when released, shuts off the coolant. When installing the air vent, the valve is pushed down, opening access to the system. It is very desirable to install this simple device in centralized heating systems. It allows you to remove air vents without stopping and draining the system. You will have to remove them for cleaning. IN shared systems the coolant has many impurities that settle and clog the spool and the mechanism supporting it. If a lot of dirt accumulates, coolant begins to flow through the outlet hole. This means it's time to disassemble it and clean it. This is where the shut-off valve comes in handy. With it, you simply unscrew the air vent device, the spring is released and the hole is sealed with a gasket.
When installing automatic air vent there are several rules:
A little about prices. It has a significant variation and depends on the manufacturer, connection diameter (half-inch ones are about 10-15% more expensive), as well as on the material used. The cheapest models cost about $5, the most expensive - $15. But in different stores prices for the same models can vary greatly. For example, you can buy a Danfoss DU 15 automatic air vent for both $7.63 and $11.5. But, of course, you need to look carefully so as not to buy a fake. This is especially dangerous with well-known companies: Danfoss (Danfos), Wind (Wind) or Valtec (Valtek).
We also list prices for shut-off valves. There is also a spread, but not so significant: from $1.1 to $1.8.
Manual way to remove air from batteries
And yet, more often manual models are installed on radiators. And the most common of them is the Mayevsky crane. It is small, simple and effective. It is also called a needle air vent valve.
It is a metal washer with a thread applied around the circumference. The washer has a through cone-shaped hole with threads. The hole diameter is very small. On one side 1-1.5 mm (towards the radiator) and about 5 mm on the other.
Diagram of the Mayevsky crane
A locking cylinder is screwed into the hole, which is also threaded. When closed, it blocks the coolant flow completely. The cylinder is unscrewed, the cone is lifted, the hole opens. If gases have accumulated in the radiator, they come out. If there are no gases, the coolant comes out. But there cannot be a lot of it: not much will leak into a hole with a diameter of 1 mm.
In some models, a plastic disk with a drain hole (also about 1 mm in diameter) is attached to the body. This disk turns freely around a horizontal axis, which allows you to set the drain hole in a convenient position.
How to use the Mayevsky crane
If you have air collected in your heating radiator, you need to take a special key ( small piece plastic, which comes in each kit) or a regular screwdriver. Insert it into the slot on the air vent disc and turn it one or two turns counterclockwise. At the same time, a hissing sound will be heard - air begins to escape through a small hole next to the disk. Gradually, water begins to come out along with the air (the stream is very thin, don’t be alarmed). When the stream becomes continuous, close the tap by turning the key (screwdriver) in the opposite direction.
This procedure is usually needed when starting up the system, and from time to time throughout the year. After graduation heating season You also need to check for the presence of gases - it is forbidden to drain the coolant, since “dry” the inner surface of the radiator corrodes very quickly. And since the coolant remains in the radiator, reactions continue to occur. What you can do to remember to bleed the air is to turn the tap a little after turning off the batteries. Then there will be a small hole through which, without pressure, water (coolant) will not flow, and the gases will gradually escape.
Another option for a manual air vent
This valve is produced by the same companies that make automatic valves. There is also a cone here, but the design of the device is somewhat different. In addition there is a handle. It is, of course, more convenient to use than a key. The principle of operation is similar: turn in one direction, the cone moves away from the hole, the air comes out. Turned it in the opposite direction and closed the hole.
A little about prices. The price of the Mayevsky faucet is $1.2-1.5, manual valves of other types start from $2. It’s hard to say how much the most expensive one might cost, but there are “antique” models that offer to buy for $20.
How to install manual models
The Mayevsky tap is screwed into the adapter. Usually there are no problems with selecting diameters, since this device comes in a mounting kit for radiators. Only during assembly you need to remember that if you install it on the radiator on the left, you must first screw the air vent into the adapter and tighten the threads (with a regular wrench, without using excessive force). After this, you can screw the assembly into the manifold. The whole installation.
Another option hand-held device Installation is no more difficult. The process is the same as when installing an automatic one. In this case, it is also desirable to install it in tandem with a shut-off valve (the Mayevsky valve cannot be removed without stopping the system). If you are installing with a valve, screw the valve into the adapter from the installation kit. Then install this assembly on the radiator. And then you can installed valve screw in the air vent.
Sometimes, to ensure tightness, winding is screwed onto the thread. You just don’t need to wrap it around a lot, and you can’t use paint. It is better to take a little sealant (you can only use sealant).
How the Mayevsky crane is installed is demonstrated in the video.
Results
In properly designed systems, it is quite sufficient to install manual water vents to remove air from radiators. If gases accumulate regularly, it is easier to install automatic devices and not constantly check whether the batteries are heating up, or whether it is time to release the accumulated gases.
Air in the heating system is the source of many problems. Because of air jams The circulation of coolant in the radiators is disrupted, as a result, their heating noticeably deteriorates. Cracking and clicking sounds appear in the pipes. To solve this problem, it is necessary to install automatic and manual air vents for the heating system.
The most common types of air vents are:
- automatic;
- mechanical (manual, Mayevsky crane).
Their common goal is the same - to remove accumulated air from the heating system.
Auto
As the name of this device suggests, it works independently and does not require human intervention, as it automatically removes air from the network. The gas outlet valve is located on the top or side.
The automatic air vent consists of the following parts:
- frame;
- housing cover;
- float;
- jet;
- holder;
- spool;
- spring;
- valve and body o-ring;
- cork.
Attention! An automatic air vent should only be installed when vertical position. If it is placed differently, the device will begin to leak.
The connecting threaded part of such an air vent can be straight or L-shaped (angular). Devices of the latter type are often installed on radiators instead of the Mayevsky tap.
The operating principle of an automatic air vent is as follows: air enters top part housing, lowering the float and displacing water from the device. As the float descends, it acts on the holder, which opens the valve that releases air to the outside. Once all the gas has come out, water fills the body and lifts the float back up. At the same time, the holder closes the valve with the air outlet hole so that the coolant does not leak out.
Devices automatic type react strongly to the quality of the liquid in the heating system. To ensure that they last as long as possible without interruption, it is recommended to install cleaning filters.
Mechanical
The body of the manual release is usually made of brass, has simple design and small sizes. The main part of the entire Mayevsky crane is shut-off valve needle type. To engage it and expel air, you need to turn the screw counterclockwise one turn with a special key, screwdriver or hand, depending on the model of the device. The needle opens a hole and gases escape through it. At this point, a faint hissing sound will be heard. As soon as all the air has escaped, coolant begins to flow out through the hole. After this, you need to tighten the screw all the way.
Attention! If the heating system is forced, then the circulation pumps should be turned off before bleeding.
The only drawback mechanical devices– all actions with them have to be carried out manually.
Installation
In single pipe systems with natural circulation plays the role of an air vent expansion tank open type. If installed closed membrane tank, then an automatic air exhaust device must be built into the heating system.
Pipes in networks with forced circulation must have a rise from the main riser to the others. Automatic air vents are installed at the highest points of the network, since this is where gas collects, as well as in places of probable accumulation (collectors).
The Mayevsky tap is installed on radiators on the top right or left side. The majority of all gases are removed from the heating network through automatic air vents, and only a small proportion through mechanical devices.
Attention! First, remove air from the system, and only then from the radiators.
To make it easier and faster to replace the automatic air vent, it is recommended to install it on a shut-off valve. When unscrewing the air vent device, it cuts off the coolant.
Solving automatic air vent problems
Due to poor-quality coolant in automatic devices, the needle becomes coked over time, or rather, salts settle on it. As a result, it cannot completely close the air outlet hole. The result is that the coolant begins to flow out through it. To solve this problem, you need to remove the air vent, open the cover and clean the needle and rocker mechanism of all impurities. Then reassemble and install in place.
Another most common failure is cracking of the rubber seal located in the housing cover. As soon as the ring breaks, coolant begins to flow out from under the cap. To fix this problem, you must either replace the O-ring or wind FUM tape onto the thread instead.
Price
The cost of a mechanical air vent starts from 40 rubles. For automatic devices, it depends on the manufacturer, the connection diameter and the material from which it is made. The most the best option Air vents made of brass are considered, since steel ones are susceptible to corrosion. The price of brass devices starts from 400 rubles.
Reasons why air gets into the system
Most often, air locks appear in the heating system after long downtime, repair or replacement of any parts. Also, due to too rapid filling of the network with coolant, air bubbles form, so it must be filled slowly. After the initial filling of liquid, air pockets always appear in the system. Since dissolved oxygen is present in the water, when heated, it begins to evaporate and rise to the highest places, slowing down the circulation of the coolant.
In addition to noise and poor heating of radiators, the air in the heating system contributes to corrosion of pipes and pressure surges in the network. It is especially dangerous for circulation pumps wet type, since during operation their sliding rings require constant lubrication with coolant.
In order for the entire network to last as long as possible, all radiators, boilers, collectors and other places where the passage of air is difficult should be equipped with air vents. If, after releasing the gases, the system still does not warm up properly, it is recommended to drain all the coolant to flush the pipes, since the cause of poor circulation may be excessive contamination.
Content
- Air in the heating system - why is it bad?
- Design and principle of operation of an automatic air vent
- Types and markings, popular models
- Installation in a heating system
The presence of air in the heating system is extremely undesirable. However, he gets there one way or another. This has a very detrimental effect on the quality of operation of the heating system as a whole and reduces the service life of its individual components. In order to remove accumulated air, an automatic air vent is needed.
In this article we will talk in detail about this device, the principle of its operation, marking features and popular models, as well as how to properly install it in the heating system.
Air in the heating system - why is it bad?
It would seem that the heating system is closed, completely filled with coolant, where does the air come from? There are several ways for it to appear inside, among them there are several main ones:
While filling with coolant
While you're filling out heating system water or other coolant, it mixes with air. It is almost impossible to avoid this, so you have to take it for granted.
Through poor connections
Poor installation of the heating system or other heating device, poor quality, defective or broken shut-off valves or other elements - all this leads to air penetration inside.
Chemical reactions
In addition to air, other gases can accumulate inside. For example, if you use a coolant with high acidity and aluminum radiators, then as a result chemical reaction hydrogen will be released.
As you can see, there are many reasons for this phenomenon. But why is this so bad? The first thing this leads to is cavitation. It significantly accelerates the wear of equipment and leads to noise during its operation. The second reason is corrosion. It destroys the elements of the heating system and carries their particles with the coolant flow to other devices, clogging and interfering with them. normal functioning. Thirdly, the presence of air reduces the actual heat transfer heating devices and leads to disruption of the pumps. It can even cause a rupture of the boiler casing.
To eliminate all these problems, an automatic air vent is used. Let's figure out how it works in the heating system and what components it consists of.
Return to contentsDesign and principle of operation of an automatic air vent
The design of this small device is very simple. Inside the brass body there is a polypropylene float which is connected via a rocker arm to the spool. As the body fills with air, the float moves down and opens the exhaust valve. The freed space is filled with water and the rising float closes the spool. To prevent various debris, dust and dirt from getting inside the spool, its outlet hole is closed with a plastic cap.
Photo 2: Design of an automatic float-type air vent There are models with a slightly different implementation of this process, but in general it is always the same: when the float is down, the valve is open and releases air; if it is raised, the spool closes and the device accumulates gas again. This cycle is repeated again and again automatically.
Return to contentsTypes and markings, popular models
There are several types of automatic air vents. All of them are divided into two large types: automatic and.
Depending on the diameter of the threaded connection, they are of two types: 1/2 and 3/4 inches. The first is better known by Russian markings as an automatic air vent valve Du 15, the second - Du 20.
According to the method of fastening, they are divided into classic straight and lateral. For air vents of the second type threaded connection rotated 90 degrees. The air release valve may also be located on the top or side. Various modifications are produced by the manufacturer to facilitate installation in difficult places in the heating system or for mounting on the side of radiators.
Photo 3: Automatic air vent DN15 “Valtec” VT 502 with shut-off valve On domestic market The two most famous manufacturers are Valtec and Danfoss. Valtec supplies Russian market automatic air vent VT.502 with mounting diameter 1/2 (DN15). The model has proven itself well and is very popular among installers autonomous systems heating in private houses. It has a brass body coated with a layer of nickel, which is designed for a maximum pressure of 10 bar and a temperature of 110 °C. Average price, according to which at the moment you can buy this model, it costs 280 rubles.
Photo 4: Automatic air vents 1/2 "Danfoss" series "Eagle" and "Wind" Danfoss takes second place. It produces automatic air vents in two series: “Eagle” and “Wind”. For general technical specifications, they are only slightly different in appearance. The models are made in brass cases and are designed for a maximum pressure of 10 bar and a temperature of 120 °C. In addition to the standard mounting thread DN15 (1/2), Danfoss also produces automatic air vents with fastening 3/8 (DN10). Prices for these devices are also within 300 rubles.
Water supply system fittings
We are so accustomed to such a benefit of civilization as hot water that we no longer think about where it comes from. In a city apartment, you just need to open the tap for this. But what about country house, cottage? After all, there, unlike in the apartment, no one heats the water for us. You'll have to do this yourself. However, in this case there is nothing complicated. You just need to foresee where, how, and most importantly, from what the water will be heated - different ways heating leads to differences in the fittings used.
In this article we will only consider devices indirect heating powered by a boiler or electricity, and pipeline fittings necessary to supply water from the source to the consumer, i.e. to you and me. The system presented in the diagram below can be divided into several parts: supply cold water to the boiler, hot - from the boiler to the consumer, cold water supply to the consumer. There is no water circulation.
Ball valves
With its name and good characteristics the faucet is obliged to the design - inside it there is a ball (usually made of brass) with a through channel. When its direction coincides with the axis of the pipe - throughput maximum. When the ball is turned (using the rod and handle) 90°, the valve closes.
Why is it better to choose this particular tap rather than a gate valve or an ordinary valve? Because it is smaller than a valve, and on its working surfaces, unlike various valves, long work V aggressive environments(like our water) no salt deposits occur. For ball valves high degree tightness, long term services (particularly due to the lack of rubber gaskets), and they are convenient to use. Ball valves can withstand pressures of about 5 bar, maximum temperature+90 degrees Celsius and do not require maintenance.
During operation, the ball valve should only be fully open or fully closed position. Using it as a control device is unacceptable, as this will lead to rapid wear.
The ball valve has several types of handles. The name depends on what the handle looks like, for example a butterfly, a lever, etc. For a cottage, it is better to choose a faucet made of brass (for example, brand J1C59-1). It can also be chrome plated.
There is another small, but very important nuance- ball valves must be installed at the entrance (in this case they are called inlet) of cold water supply in order to de-energize the entire system if necessary. They are located on the pipe in any position, in places convenient for use. The number of cranes depends on the supplied equipment. So, due to the need to periodically replace the cleaning filter, so as not to completely disassemble the system, the tap is placed before and after the filter (see diagram). However, in this case it is possible to use various types valves and dampers.
Most domestic and imported pressure gauges are manufactured in accordance with generally accepted standards, so pressure gauges various brands capable of replacing each other. The only difference is the price of the device. The instrument scale is limited to 6 bars, the number of divisions depends on the maximum value. But for the average consumer this does not play a special role. When choosing a pressure gauge, you only need to know the thread of the fitting so that there are no problems with installation.
If the pressure gauge is mounted on a pipe, you should consider convenient location device, also taking into account the diameter of the housing. Pressure gauges are placed before and after the filter in order to find out from the difference in instrument readings whether it is clogged or not. But it is also possible to omit one pressure gauge if the pressure reducer, which is installed after the filter, already has a pressure gauge.
Strainer and fine filter
Any foreign impurities in the water can damage not only the pipes, but also the fittings installed on them. A clogged tap begins to drip over time, which leads to a loss of up to 150 liters of water per month. Due to leaks, rot occurs, bacteria appear, and corrosion begins. The system may even rupture. And it’s all because of hard water, that is, lime-containing water. If you think your water is perfect, pay attention to the tiles in the bathroom or shower - limestone deposits on them directly indicate the opposite.
Filters are introduced to purify water. For example, ordinary mechanical filter rough cleaning will rid the water of grains of sand, small fragments of pipes, scale and other mechanical particles. Some filters have a backwash function, i.e. They self-clean during operation, which extends their service life. Typically the body is made of brass, which contains zinc. During operation, zinc particles may be washed out from inner surface device. To prevent this, it is better to use filters made of dezincification-resistant brass (DZR-brass). This material guarantees long term operation.
As a rule, manufacturers make a combined water supply unit that combines a pressure gauge, a filter with backwash, pressure reducing valve and shut-off valve. It should be noted that drinking water also install filters fine cleaning, delaying more fine particles. Carbon filters capable of purifying water even from microbes.
Pressure reducing valve
This device, in the event of surges in water pressure (up to approximately 30% of the nominal value), reduces it to a predetermined level. Most pressure reducing valves are initially set to 3 bar. To change it, use the adjusting screw. Inside the device there is a membrane that reacts to pressure fluctuations in the system, and a spring that compensates for them. The pressure reducing valve is a rather loud device, but some manufacturers use a special form of the reducer to reduce the noise associated with its operation.
The valve body is usually brass, sometimes chrome plated to extend service life. Some are available complete with special devices, for example, with a pressure gauge. The operating temperature of the reducer is up to + 80 degrees Celsius, and the maximum outlet pressure is about 6 bar. This is the pressure that the boiler (water heater) can withstand. The reducer is installed at the cold water inlet into the system. If the water supply is not centralized, but from a well and the pressure does not exceed 5 bar, then it can not be installed.
It is a small “tube” with a seal inside that allows water to flow in only one direction. Operating principle check valve can be compared to the operation of a door on a spring, which allows a person pushing it through only in one direction, and then immediately closes.
Place them in front of the expansion tank and in front of the thermostatic mixer. The operating temperature of the valve is up to 110 degrees Celsius.
Relief valve and expansion tank (or hydraulic tank)
Water, heating up in a boiler (water heater), expands and increases in volume by 10-15%. This liquid needs to be removed somewhere so that the pressure in heating device did not exceed its maximum value of 6 bar. This is why it is necessary expansion tank. It is installed on a pipe supplying cold water. The maximum operating pressure is 10 bar and temperature is 99 degrees Celsius.
The hydraulic tank has two cavities - for liquid and for air, separated by a rubber membrane. When heated, the pressure increases, excess water raises the membrane in the expansion tank, compressing the air and occupying a larger volume, that is, part of the water goes into the hydraulic tank, which prevents further pressure growth. When the pressure in the network decreases, the tank releases an additional volume of liquid into the system, preventing a further decrease in pressure. The volume of the tank must correspond to 5% of the volume of the water heater (boiler).
As a rule, these are tanks of 5-30 liters. There is a nipple in the upper part of the hydraulic tank, where, if necessary, a pressure gauge is temporarily screwed in to control the pressure or a device for pumping air. A relief valve, or, as it is also called, a relief valve, is installed before the expansion tank. It not only lowers the pressure by pouring out “excess” water, but also simplifies the problem of removing the hydraulic tank, for example, if it is damaged - there is no need to disassemble the entire system. Relief valve connected to the sewer either directly or through a drain funnel (faucet). It is prohibited to place any fittings between the valve and the expansion tank. The vent is sealed and cannot be disassembled or attempted to be adjusted. This should only be done by a specialist.
There is practically no difference between relief valves and safety valves. Both devices are installed in front of the expansion tank and are used to counterpressure water in the pipes. The size of the discharge hole is one step larger than that of the connecting hole. This is necessary for quick disposal from “excess” water. The spring located inside the valve is made of nickel steel. It is better to choose a brass valve itself. Its maximum operating temperature is 90 degrees Celsius.
The outlet pressure provided during manufacture is from 1.5 to 6 bar. By pressing in the safety cover, the valve is protected from resetting the set value - this cannot be done without damaging the integrity of the cover. If the pressure in the pipe rises sharply and the temperature rises, the valve opens and the water is drained either into a funnel or into the sewer, thereby equalizing the pressure. When there is some kind of disturbance in the system, the safety valve may leak.
But there's nothing wrong with that. You should be wary and look for the cause only if it begins to leak. Safety valve mounted in any position on the pipe in close proximity to the boiler. According to the rules of Rostekhnadzor, it is prohibited to install any shut-off valves between the valve and the boiler (water heater).
Air in systems leads to premature corrosion of pipe materials and fittings, causes noise and creates air pockets that prevent the right flow water and reduce heat transfer. It is released using air vents, both manually (Maevsky tap) and automatically. The design of the air vent, which releases only air but not water, is very simple. Inside the brass body, a hollow plastic float moves freely, connected to the spool. If there is no air in the air vent body, the float is in the uppermost position, and the spool closes the hole in the air fitting installed in the brass cover. The cap protects the air channel from dust and dirt, and also allows you to close the air vent in emergency situations and during installation work.
To dismantle the air vent without emptying the system, it is recommended to place a shut-off valve in front of it. In its brass body there is a spool, held in the upper position by a spring. When the air vent is installed in the upper thread of the shut-off valve, the valve spool opens. Use an open-end wrench to screw the air vent onto the hexagon of the housing located under the flask. Do not clamp it by the body flask with a pipe lever wrench (KTR). Design dictates vertical installation, otherwise the float will not work. The air vent is installed on a water heater (boiler) - this is, as a rule, a Mayevsky tap. It has a maximum response pressure of 4 to 6 bar and an operating temperature of up to 120 degrees Celsius.
The temperature of the water supplied from the water heater (boiler) must be above 75 degrees Celsius in order to kill all pathogens (legionella) contained in the water. A thermostatic mixer helps avoid burns in this case. It combines hot and cold water flows - and water at a given temperature is supplied to the consumer.
Thermostats can be already set to a certain value by the manufacturer or have an adjustment range (on request from 25 to 48 or from 35 to 65 degrees Celsius). The cover protects against accidental reinstallation. The device can be mounted in any position. Body - chrome plated brass. Maximum flow water depends on the selected model.
Thermometer
It is placed on the supply pipe hot water after the thermostatic mixer. It is used to regulate the temperature of the water that goes to the consumer. But it can be excluded from this circuit if the thermostat already has automatic setup, or the thermometer is attached to its body. There are several types of these devices, but in our scheme only mechanical ones are used. It is simply irrational to use other thermometers here.
Mechanical, or bimetallic, thermometers operate on the principle of changing the size of a bimetallic spiral (tape, spring). As the temperature increases, the spring unwinds (or twists) depending on the difference in the coefficient thermal expansion the metals from which it is made. The inner end of the spring is attached to the body, and an arrow is welded to its second end, which deviates in proportion to the change in temperature. Depending on the type of connection of the stem to the body, thermometers are divided into rear (axial) and radial. The thermometer body is made of chrome or stainless steel. Rod material - brass or stainless steel.
Collectors, despite their name, do not collect anything, but distribute water from the main pipeline to consumers. They are made from special food-grade brass that is absolutely safe for humans. The number of outlets is usually from 2 to 12, but there can be more - it depends on the size of the house and its saturation with heating and plumbing equipment. To keep the water pressure in the collector constant, the diameter of the outlet holes is approximately three times smaller than the diameter of the inlet. The longer the manifold and the smaller its cross-section, the more noticeable the pressure loss and difference in flow rate will be.
Typically, collectors are installed at three quarters with a small number of consumers. If there are many devices for which water is supplied, then it is better to install inch ones. Range operating temperature ranges from 5 to 100 degrees Celsius, and working pressure- about 10 bar.
Although the automatic air vent belongs to the category auxiliary equipment heating system, but this does not mean that it is completely unnecessary. Yes, in systems with natural coolant circulation, in which there is an open expansion tank, an air vent is useless. But in closed systems... very much to what purpose.
Why do you need an automatic air vent?
Purpose this device speaks for itself: to remove air from the heating system, and in automatic mode, without our participation.
The appearance of the air vent is as follows:
This is with a bronze body. And this is with a stainless steel case:
In the second photo, in addition to the air vent, there is also a shut-off valve; these two devices are often placed together.
Why is there a shut-off valve for an automatic air vent?
For convenience: first screw in such a valve, and then install an air vent into it; the valve has a plastic flag, which, when screwed in, the air vent presses on, thereby opening access to the heating system. If for some reason you need to disconnect the air vent, you do this, after which the valve will cover the remaining “hole”, preventing the coolant from leaking out. We repaired this air vent or bought a new one, screwed it in again - the valve opened...
How does an automatic air vent work?
The automatic air vent device can be seen in the following diagram:
It works like this. Air enters the air vent, opens the valve, through which it is released from the system. When the air has escaped, water enters the cavity under the float (3) - the float floats up, acting on the rod and closing the valve.
The following diagram shows an air vent of a different model, but they all work on the same principle:
How to repair an automatic air vent?
What problems can occur with automatic air vents?
Above the door - when the pipeline goes around the doorway:
(it happens, however, that the air vent starts to leak, and appearance... but sometimes it doesn’t work out any other way)
If there is a hydraulic arrow in the system, on its body:
Attention! Before starting the heating system, you need to slightly open the cap on top of the air vent.
That's probably all I can tell you about the automatic air vent. I hope you had the patience to read this far? Then see you in the next articles.
automatic air vent