Build Daily

August 12, 2017 18:06

Bleed screw : the characteristic and principle of operation

Surely you have heard this phrase as "bleed screw".It is intended to lower the air in the heating batteries.Without this little device is impossible to organize the work of heaters because systems are often air is formed, which prevents the normal circulation of the water.


  • Brief History
  • How does tap
    • crane device
  • As a self-install
  • crane How to serve
  • How to exploit
  • What are the advantages of working bleed screw

in any official document, you will not find the name "bleed screw", but in common parlance, this is called the crane that way almost all the plumbing.Only some may argue and say the correct name of this device.According to the State Standard, the device belongs to the "shut-off equipment" category and named as "Needle radiator air valve."We will not go far back in history to find out why in the name of the air valve.

Brief History

crane was invented in 1933 and immediately began to take root everywhere.According to research scientists, something similar occurr

ed a little earlier invention.In 1931 he invented the valve plumber Swarms.The design consisted of 2 parts, separated by a spacer.In 1932, with the onset of the heating season, the crane was successfully tested and was used to bleed air for heating radiators.The principle of operation of the two valves is similar, only different bleed screw connection "cone in cone", as well as the cross-shaped key.Overall, both devices cope with one goal - to pit formed in the air system.Over the years, a little-known plumbing fixture faded into the background, and only became widely used a crane "Majewski".


How does tap

Obviously, when the temperature in the living space starts to drop, it is necessary to look for the reasons.First - batteries warmed bad due to the fact that the system is air and the warm water can not normally circulate.Then use Majewski valve for radiators.

If you do not remove air from the system, it will not be fully filled with water, and do not expect the heat.To solve such a problem, you must install a special device on the battery, which is widely used to remove air from the radiators.We are talking about the central heating systems.Typically, individual heating organizations such problems are rare, but because of personal motives, many owners set the bleed screw on the radiator, if in the system is filled with water.In addition, such valves must be installed and towel warmers (exception - electric appliances for drying towels).

outer flap (conventional and automatic) may be different from each other, but they share one thing - the same principle of operation.Crane - a kind of cone rod if it fully tighten, it will close the hole.


Make dampers made of steel or brass, as they are resistant to corrosion.The buyer can choose any favorite crane model.The main thing to look out for, so it's on the diameter of the thread on the outside.For each type of radiator bleed screw need to pick the size of the thread.Standard thread on the cone - 1 inch, 1/2 inch, used cranes with a small iron thread for old-style radiators - 3/4 inch.Now such air valves are used for modern radiators and floor multi-row batteries "Accord".

When buying, note the following: Majewski cranes can be normal and automatic.


device crane

Air valve arranged simple - it consists of a body and a conical screw, which is screwed in.With a small water flow rate or insufficient (when people poured water from a heating duct in the winter time for personal needs), the air accumulates system.As a result, the battery poorly heated, the temperature in the room is reduced.

Majewski valve can be opened manually without the use of special tools (depending on the valve model), using a screwdriver or wrench.


How to "bleed" air from the system:

  1. Prepare a cloth and place a bowl under the battery to water.So you do not mess up the floor.
  2. to release the air, turn the tap on half a turn anticlockwise and wait until the air has escaped.If it is very much possible to turn the tap a little bit more and wait.
  3. As soon as you open the tap, hear a hissing sound, this means that the air is released gradually from the heating system.Do not relax, because the air comes out quickly and with it will soon begin to go water.As soon as she "goes", it's time to tighten the tap, because the air is already full left.


handle even high school student can with this work.Actions are simple: tap turned, paused, closed.

If the system has forced circulation pumps (individual heating) before you start to bleed air, the pump must be switched off.If he will continue to work, do not completely remove the air out.

Majewski Crane is considered a manual device intended for installation in central heating systems.If your home heating system or closed, it is best to fit the automatic bleed screw, which does not require human intervention - it works independently, removing excess air from the heating system.It is very convenient as a crane Majewski save people from the constant water temperature control in the batteries and drain manually.

Since the threads on the air valve for the connection remained the same, corresponding to GOST Soviet times, then you will easily set the automatic crane to any radiators, though old, although modern sample.

To manually install the faucet, you will not need special tools and skills.Knowing how to construct the heating system, you can easily cope with the task.

As a self-install the valve

Before you begin to install the tap, the water must be drained from the system, unscrew the cap of the radiator (top) and a place to install the faucet.If the valve is to be mounted on the central heating battery, it is best to mount the crane in the summer, when the system is fully drained water.


consider steps, independently mounted faucet:

  1. If we need to put Majewski tap for cast iron radiators, then have to work.You will need to drill a hole at the top, at the very end cap, then make the thread and screw the tap.
  2. If you use a centralized heating, then install an automatic valve is undesirable.Due to the fact that the water is constantly circulated, it gradually becomes soiled, so the crane can severely clogged and you have to clean it constantly.And when you consider that in the big houses are often cut off heating, the air is formed quickly.
  3. Because the central nervous system often have water hammer, you should consider the option of purchasing "omes" faucet or "MS-140", it can withstand up to 15 bar and temperature of the water in the system to + 150 ° C.

How to serve

air bleed screw is considered to be reliable, since for many years he regularly works.When present in the system of pollution, large particles of debris, that little tap hole may become clogged.Then the device should be freed from the debris that accumulates inside or in a plastic lining.This is easily done by cleaning the hole with a needle or pin.

If you did everything right, and the battery is not heated, so clogged radiator itself.Then, need expert help.Perhaps it will be enough just to clean the battery.Be prepared and to the fact that you can advise to install a new heating radiator.

If the valve has worn, it must be replaced.This requires a special tool - a gas or an adjustable wrench.You need to hold down the battery plug and pull it out, unscrew the faucet.


How to exploit

These simple guidelines will help you learn more about how to properly operate the bleed screw, so that he has served for many years:

  • install the air valve on the heating battery only;
  • sometimes to serve tap, a screwdriver is not enough.Especially, if the crane is located in an inaccessible place, for example, in a niche.Then you should think about purchasing a key;
  • when you fold the air, remember that should not be near any naked flame sources (eg fireplace) or you are working with a lit cigarette.Even the smallest spark can trigger a fire;
  • not keep Majewski valve in the open position, as your heater can quickly come into disrepair;
  • if you are a long time did not use the crane, the thread can rust and it will be very difficult to unscrew.You need to drop a little kerosene on the thread and wait for 1-2 minutes.Now you can easily unscrew the thread.Only carefully so that the air began to come out gradually.

What are the advantages of working bleed screw

To prevent operation of the heating system, you can use alternative devices.For example, to install the ball valve.Still Majewski crane will be beneficial to look at the heater, due to its ergonomic design.

Also do not forget about that in an apartment building if you have not installed the crane Majewski, a high risk of flooding the premises located below.And this is - damaged nerves and extra expenses for damages.That is why the cost to purchase and install the crane Majewski.The cost of the air valve in comparison with spoiled by the flood of property - is minimal.The valve is about 20 to 60 rubles.


Compared with a conventional automatic valve, the latter, though looks beautiful, but because of the dirty water is often clogged.Because of this, the crane can go wrong and just not work.

crane advantage in the fact that it is a reliable and easy-to-use locking equipment.It can be installed on any battery as comes bundled with rubberized O-ring.You only need to properly install the valve and from time to time to rotate the screw to get rid of airing.

important if you live on the top floor, then your actions will determine the fate of inhabitants of a riser.If you promptly remove air from the system, all residents of the house or riser will be hot battery, and thus the heat in the house.

installing in his apartment Majewski crane, you save money on heating.With timely control the temperature of radiators, cooling you prevent them, which means that the room will warm uniformly, and you do not have to include electric heaters to keep warm in cold weather.

To learn the principle of work of the crane Majewski, you watch this video: