The Maevsky valve is designed to vent air from the piping system, which improves the circulation of hot water in the heating system. This device is also popularly called the Maevsky crane, and in accordance with the regulatory requirements of GOST it is a radiator needle air valve.
From the history of the Mayevsky crane
More recently, these types of air vents on radiators were not used. Instead, they used water taps of the usual design. This led to the fact that an uncontrolled intake of process water was made from the heating system, which required the development of new devices that would significantly reduce water consumption. This device was the Maevsky valve.
Causes of air congestion
The occurrence of air congestion leads to the fact that radiators warm up worse, which, in turn, leads to uncomfortable living conditions. This occurrence is possible with:
- installation of a new heating system;
- drainage of water from pipelines and repair work;
- installation of radiators;
- the manifestation of corrosion on the metal pipes;
- depressurization of the circuit.
The need to use a Mayevsky crane
As noted above, with the help of this device one of the main problems of the heating system is solved - air removal.
In addition, during the formation of air in this system, hydrolysis reactions of water with internal walls made of metal occur, which is especially typical for aluminum batteries that are made without anti-corrosion treatment. In this case, hydrogen is released. The use of the Mayevsky crane allows to remove this problem.
Varieties of the valve (crane) Majewski
There are 3 main varieties of this device.
Here they are:
- The simplest Mayevsky crane is a manual type. A special key is used to open / close it.
- Majewski automatic valve - is a cylinder made of brass, although recently manufacturers began to produce chrome steel products, which have a lower price, but also a shorter service life, so you should choose a device made of stainless steel or brass. In accordance with the national standard, this device cannot be considered a Maevsky crane, since it does not have a needle valve, instead of which a plastic float is used. Nevertheless, it is referred to as such, since the function it performs corresponds to the Mayevsky crane. With the formation of air jams, the mechanism begins to move and thereby causes the device to open.
- Mayevsky valve with built-in fuse - the last device is necessary for regulating the pressure. If the specified parameters are exceeded, the crane is triggered and the coolant is released, which avoids water hammer. It is mainly used for polypropylene and plastic pipes.
Operating principle
The heating system must be constantly fed with a coolant, in which case water is used. A small portion of air enters with it. In those places where the low speed of water and the same pressure, air can accumulate in the pipeline and form bubbles.
When the accumulation of air reaches a critical volume, air jams occur. The principle of operation of the Mayevsky valve is that air is emitted from the radiator using special tools and devices, as a result of which the air plug is eliminated, and the heating system begins to function normally.
Removing air from the heating system
Before you start working with the Majewski valve, you need to remove all objects that may interfere with the work, as well as which may be damaged by water flowing from the heating system. Under the valve substitute any vessels (buckets, jugs, bowls, etc.) in order to prevent spillage of water on the floor and walls. Next, an adjustable wrench or a screwdriver rotate counterclockwise. The rotation is stopped as soon as the air stops coming out of the radiator, which can be judged by the appearance of a hissing sound. This is the principle of operation of the Majewski valve.
After the valve hiss, it is necessary to wait for an even stream and immediately block the opening with the reverse movement, since hot water can go.
Use of the Mayevsky crane in separate rooms
Many apartments and houses have a bathroom, in which in many cases a Mayevsky valve for a heated towel rail is provided. He is equipped with it due to the fact that, like a radiator, a heated towel rail can be aired. At the same time, this valve is located strictly vertically using a special tee, which will translate the axis of the installed device into a horizontal position.
The vertical heating system used in multi-storey buildings provides for the presence of Mayevsky valves on the top floor, which allows air to be vented from the heating system not of a separate apartment, but of the entire riser.
In one-story houses, a horizontal heating system is mainly common, so it is better to put a Mayevsky crane in the upper part of each radiator.
How to use the Majewski valve
Before you start air bleeding, it is advisable to turn off the pump that drives the coolant through the system so that air accumulates at the top of the radiator to facilitate its descent.
The hole for the air outlet must be located when mounting the Majewski tap down, since it is quite difficult to place the dishes for collecting water at the top. The ceiling and walls may be splashed, in addition, people in the room where the air is vented may be burned.
To facilitate the rotation of the screw, in case of prolonged non-use, it must be lubricated with kerosene or special compounds.
Mayevsky’s crane cannot be in the “open” position permanently, as this can lead to flooding of his apartment or the apartment of neighbors.
Together with the air, gas escapes from the faucet, which can ignite; therefore, when using the Majewski faucet, you must not smoke or use fire in any other way.
Technical characteristics of the Mayevsky crane
When buying, you need to choose a Maevsky crane that would have a suitable diameter to the radiator futors located in their upper part.
Basically, its dimensions (threads) are indicated in inches. One of the most common is a 1/2 inch Majewski valve. On sale you can also find cranes with a diameter of 1 inch and 3/8 inches. Common models also include a 3/4 inch Majewski valve. If the mounting dimensions of the mounting locations of the valves do not coincide with those purchased, it will be necessary to purchase adapters and other consumables.
Cranes are available in various sizes with nominal diameters of 15, 20 and 25 mm, which allows it to be used in various components of the heating system. The operating pressure for the valve is 10 atmospheres, and the operating temperature is up to 120 degrees, which when heating central heating radiators to 60 degrees, and with autonomous heating usually not more than 80 degrees is more than enough.
Valve Design Features
The locking screw is the main component of this device. It has a conical shape in the end part, which ensures a "fit" fit into the hole with a diameter of 1.5-2 mm. Outside, the screw is a polyhedron with four or six faces with a slot. This shape of the head provides its free rotation with a special wrench or screwdriver. Inside the screw, longitudinal grooves are made, through which the passage of air is ensured.
From these grooves, air passes into the chamber, which is closed, as a rule, with a polymer cuff. This camera has an outlet with approximately the same diameter as the through hole. The tightness of the system is ensured due to the fact that the valve body is mounted on a threaded connection with the stuffing box gasket, and in the closed position the valve mechanism overlaps the through hole.
In the automatic Majewski valve, there is a float inside, which, in the absence of a gas medium, props up with a lever the spring holding the inner tube, thereby ensuring the tightness of the system. In the event of air, the float falls through, the spring pressure weakens, the inner tube opens an outlet through which air flows by gravity to the outside. After it leaves, water fills the chamber in which the float is located, which contributes to the floatation of the latter, as a result of which it closes the outlet through pressure on the spring with a stopper.
Mounting points for the Mayevsky crane
As already mentioned above, in vertical systems, these elements are installed on batteries located on the top floor. In addition, they are mounted on those elements of the system that are connected to the riser below the upper connection point.
With a horizontal system, all radiators are provided with Maevsky cranes.
When installing underfloor heating, Maevsky cranes may not be mounted at all, automatic cranes may be installed. In the case of their use, they are installed at the farthest point of the underfloor heating system.
Mounting technology
The operation of the Mayevsky valve in the form in which it should be can be ensured only if it is installed correctly. The valve must first be of a suitable diameter. Its installation should be carried out only after the complete discharge of water from the system. Before mounting, the cap located on the side of the battery is removed, and a Mayevsky crane is screwed into its place.
If there is a need to install this device in a cast-iron battery, it must be borne in mind that it does not have a hole in the plug, so it must first be drilled with a drill with a 9 mm metal drill bit inserted into its chuck. In this hole we cut the thread and screw the valve. However, it must be borne in mind that the thread can be torn off with a water hammer, so it is better to install automatic Maevsky cranes adapted to the landing dimensions of the plugs.
At the junction, it is desirable to install a silicone or rubber gasket, as well as a winding made of flax.
The lineup
On the plumbing market today there is a wide variety of Mayevsky faucets from various manufacturers located both in Russia and abroad using various components and materials. Metal or plastic keys for these devices are sold separately.
Prices for valves range from 21-51 rubles. with the manufacturing material chrome steel (at such prices you can buy cranes from the manufacturer LLC Promart, Kazan) up to 475 rubles. - Mayevsky’s manual tap made of chrome-plated brass manufactured by Promarmatura LLC, Barnaul. Also on the market are tees with a Mayevsky crane (cost about 600 rubles), keys (cost between 20-120 rubles). An automatic Mayevsky crane costs about 250-700 rubles, while a full-bore crane for cast-iron radiators is more expensive.
Finally
Thus, the principle of the Majewski valve becomes clear. Its main function is to remove air from the heating system, which increases the efficiency of its operation so that people living in houses in which Mayevsky taps are installed on radiators do not experience discomfort due to insufficiently warmed batteries. The device is relatively simple, so everyone can use it to bleed air, replace or install a valve if necessary.