Water heating mains have a characteristic feature. When filling pipelines with water, part of the system remains occupied by airbags. The normal operation of water heating in such cases is not ensured, so the air from the pipelines must be removed manually.
The Maevsky crane helps to get rid of air jams - the simplest mechanism for bleeding air by hand. In the article we presented, the principle of the device’s operation is examined in detail, and alternative options are considered. Our recommendations will be useful in installation and operation.
The device and the principle of operation of the device
Majewski’s usual cranes were made under the control of a special key or a metal screwdriver. That is, in fact, such products cannot be called automatic devices.
The modern prototypes of Maevsky’s taps - automatic air vents - have been somewhat improved by the designers.
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After filling the heating circuit with coolant and periodically during operation, all forced circulation systems need to be vented. Bleed through automatic or manual air vents.
Air vents are installed on closed systems that do not have a direct connection with the atmosphere. To release air, Maevsky cranes are equipped with a channel that opens when the outer nut is turned
To make the turn, different models of the Mayevsky crane are equipped with stationary plastic or metal caps, handles in the form of a key
If there are concerns that in the absence of adults, curious researchers of their own estates may open the tap, it is better to install a device with a removable key
In any of the modifications of the Mayevsky crane there are no complex and wearing parts. Because they almost never break, occasionally, however, it is necessary to change the seals
In order to bleed air from the battery, the Mayevsky crane is simply turned so that the air channel opens. The air comes out with a hiss for about 5 minutes. Then coolant will pour out of the channel - this is a signal that all the air has left
Most of the radiators manufactured these days are manufactured with the Mayevsky crane originally installed.
Air from the entire heating system is vented automatically using a more sophisticated device. However, its operation is similar to the principle of operation of the Mayevsky crane - air leaves through an ajar channel. Only for this you do not need the participation of the owners
Manual air bleeders
System air exhaust duct
Air vent handle
Removable key for manual air vent
Typical Mayevsky crane design
Venting the radiator
Mayevsky crane installed in a radiator
Automatic air vent for heating
Automatic models work without any outside interference.
But in plumbing practice, there are various constructive variations of Mayevsky taps:
- direct stock hand;
- angular stock hand;
- float vertical automatic.
Manual and automatic options are somewhat different in that the former can be mounted in almost any position, and the latter exclusively in a vertical position.
Hand structures are traditionally mounted directly in the body of radiator panels or batteries. Automatic air vents, as a rule, are designed for installation on highways at points of the heating system that are difficult to maintain.
It shows the variety of designs of Maevsky faucets, which are most often found in plumbing practice. The set includes manual, automatic products, as well as combined with a safety valve
The principle of operation of the Mayevsky crane is based on the interaction of the simplest parts. Manual designs actually represent a conventional needle valve.
Elements of such a valve are:
- The body is metal.
- Threaded rod with feedthroughs.
- Cap with air outlet.
- Sealant rubber ring.
The material for the manufacture of Maevsky cranes is traditionally selected brass. True, a separate part of the mechanism — a cap with an air channel — can be made of kapron, nylon, or high-temperature plastic.
Modification of the air vent for home heating radiators. Design option for a special key. Convenient and practical crane for domestic use
The brass body of the device is threaded by the outer diameter of the lower part. With this part of the casing, the tap is screwed into the seat of the heating radiator plug.
Operation of the manual crane mechanism
Everything is simple. In the normal state, the screw of the control rod is screwed into the annular ring of the drain hole with the needle part as far as it will go.
When it becomes necessary to free the system from the air congestion in the radiator, the plumber (or landlord) unscrews the screw 2-3 turns with a key or a screwdriver. Due to the large difference in the density of water and air, the latter leaks first through the opening outlet.
Further, the air flow rushes through the longitudinal grooves of the rod and enters the area under the capron cap. From there, air mass is ejected through the outlet channel. As soon as the air flow stopped, and water flowed after, the plumber turns the screw of the Mayevsky crane to the stop. This completes the venting procedure.
Mayevsky’s valve is installed extremely simply, because breakdowns with it are extremely rare, and the device works flawlessly
Periodically, the procedure for removing air from the circuit heating is repeated, since it is not possible to lower the entire volume of air at a time.
The principle of operation of automatic air vents
The action of the automaton, a follower of the Mayevsky crane, is somewhat different. The principle of operation of a similar product, but acting automatically, differs significantly from the manual standard. An automatic air vent valve is housed in a cylindrical housing. A float mechanism is installed inside the cylinder.
The lever system float mechanism is connected with a needle rod. In this design, the stem has a vertical arrangement. Its needle end acts as a valve that blocks or unblocks the opening of the upper part of the cylinder. An air-water inlet is provided at the bottom.
Scheme of automatic modification: 1 - device case, 2 - cover on the thread, 3 - float, 4 - nozzle, 5 - holder, 6 - spool, 7 - spring, 8 - sealing element, 9 - plug, 10 - sealing ring
Upon the presence of water inside the cylinder of the air vent, the float is raised by pressure. The pressure force presses the needle portion of the valve. That, in turn, closes the upper outlet.
But as soon as air gets inside the cylinder, the force of the water pressure on the float weakens, the needle part of the valve goes down. The upper calibration hole opens, through which air is thrown out. As the air bubble disappears, the cylinder fills with water again. The valve is installed in the closed position by the float.
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Top Heating Option
Horizontal low feed wiring
Dead end heating wiring
One Mayevsky crane for several batteries
How to mount an air vent?
The Mayevsky manual crane is a self-sealing device. In the kit, there is a sealing ring made of rubber, so there is no need to use any additional sealing materials.
Traditionally, the installation of manual valves for bleeding air of this type is performed in conjunction with radiator futors (1 dm x ½ dm; 1 dm x ¾ dm). As a mounting tool, a ring wrench is specially designed for working with futors and corks.
Plumbing spanner for installing radiator futorok and traffic jams. 1 - cap wrench, 2 - radiator foot, 3 - radiator cap. This tool and parts are often operated on when installing air vent valves.
Operation of Mayevsky taps (air vents) is permissible only at the pressure and temperature specified in the standards. These values are determined by the technical characteristics of the device.
Technical characteristics of the air vent
The required functional properties are presented in the following table:
Technical specifications | Permissible value | Units |
Pressure (working) | 10 | ATI |
Temperature (maximum) | 120 | ºС |
Passage diameter | 25.4 or 20.0 | mm |
Threaded diameter | 25.4 or 20.0 | mm |
Workspace | water and other non-aggressive fluids | – |
Life time | 20 – 25 | years old |
Tightness class | "AND" | – |
During operation, disturbances in the operation of devices are not excluded. A frequent cause of the loss of performance of Maevsky cranes is small garbage transported by the coolant.
If the faucet is clogged and malfunctions, it is recommended to carry out simple maintenance:
- Shut off the radiator from the system with shutoff valves.
- Release approximately 1/3 of the volume of water from the battery.
- Remove the device from the battery case.
- Clean the bore with a thin (non-metallic) sharp object.
Heating systems are not always equipped with radiators, on which there are plugs with ready-made holes for Maevsky's taps. In such cases, the terminals for air vents will have to do with their own hands. No particular difficulties are foreseen in this matter. You just need to drill a hole for the installation size of the crane and cut the thread.
The installation of taps in the housing of cast-iron heating batteries should be given increased attention. It is traditionally used products made from high quality reliable material.
The hole is drilled with a drill for metal using a drill, and the thread is cut with a tap. Of course, the diameter of the drill is chosen 1 - 1.5 mm smaller than the installation size of the crane, and the tap is exactly the size.
Features of inclusion in the heating system
There are features on the installation of air vent valves when they are screwed into the body of existing radiator plugs. Radiator plugs are usually screwed onto the left-hand thread.
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Automatic air vent in the security group
Using an air separator
Installation of air vents on each circuit
Air vent for underfloor heating system
The tap is twisted to the right, and therefore the plumbing needs to fix the cork with one key and at the same time wrap the air vent with a second. But these are technical trifles about which it will not hurt to know inexperienced inhabitants.
The formation of air jams is a problem inherent in systems with forced circulation. To bleed air, they are equipped with either an automatic air vent on the riser (right) or Mayevsky taps on each radiator (left)
The installation diagram of air vents also has some features. So, if the radiator system is built according to the vertical arrangement of devices, air vent valves are usually placed on heating radiators of the highest level.
But in the parallel connection scheme, even with a vertical structure, Mayevsky taps are placed in the heating devices of the lower and upper levels. In general, in plumbing practice, installation in each individual case is done taking into account possible accumulation of air in the system.
Instead of Mayevsky taps on each radiator or riser air duct, an air separator can be included in the system. Its action is justified by Henry's law, according to which air is released from the water and removed outside the closed loop
If the heating system is being installed according to the horizontal scheme, here, as a rule, each heating device is equipped with air vents. By and large, it is advisable to equip almost any heating system equipment with faucets that exhaust air.
Really equipped are:
- all heating batteries in the system;
- compensators, bypasses and similar devices;
- recorders and coils;
- pipelines of the upper level of the heating system.
Some circuit solutions even provide for the placement of a Mayevsky crane on heated towel rails. By the way, there are models of heated towel rails on sale, the designs of which have an entry point for the Mayevsky crane.
Tips for the good
Before deciding to purchase air exhaust devices, it is recommended that you carefully study the layout of the devices in the heating circuit.
Small-sized special keys are convenient to use in cramped conditions, where closely located other objects interfere with the use of screwdrivers
Depending on the degree of freedom of access to the equipment, Maevsky cranes of a suitable modification should be installed.
Where it is difficult to work with a screwdriver, turnkey models are better suited, and where it is difficult to work with keys, it is reasonable to place automatic devices. A careful analysis will help make device maintenance more efficient and save on purchase.
Automatic air vents are traditionally mounted on pipelines, at points of potential accumulation of air masses. On radiators, such appliances, as a rule, do not use
Hand-held devices have the most simplified design, for example, compared to automatic air vents. But, as practice shows, simplicity is the key to reliability.
If cast-iron radiators are used in the heating system, it is manual cranes that are more reliable for such a system than automatic machines. Meanwhile, the degree of reliability of the design largely depends on the quality of the metal (brass) of which the air vent is made.
Mayevsky crane assembly on a nylon plug. Design specially prepared for installation in a system based on polypropylene pipes
You can also mention the experience of introducing Maevsky cranes into heating schemes built on plastic pipes. This material reliably holds stable pressure and temperature, but is weak against water hammer.
The installation of a Mayevsky crane paired with a safety valve or a full-fledged safety group increases the reliability of the system for such cases. In general, for circuits where pressure stability is in question, it is recommended to use cranes as stabilizers.
The video demonstrates the principle of operation of the Mayevsky crane and gives recommendations for its installation:
Simple in design and convenient for maintenance, air vents are also an integral technical part of any heating system. The deliberate exclusion of devices from the system threatens to result in serious consequences, up to the thawing of batteries and pipes in the winter. It is impossible to ignore Maevsky's cranes; they just need to be selected for a specific system.
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