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How to bleed a radiator correctly

Causes and signs of airlocks in the heating system

The appearance of air congestion inside the radiators is primarily associated with the start of the heating system at the beginning of the heating season and at the end of its overhaul. But practice shows that bleeding can occur during intensive operation of the heating system. There are several reasons for this:

  • Unplanned repair work (assembly and disassembly) of the heating system elements;
  • Overheating of the coolant, as a result of which gases are released that will choke the radiators;
  • use of contaminated coolant with air impurities;
  • filling the system with additional volume of water
  • Joint nodes elements of radiators and pipelines begin to leak water;
  • The installation of the heating system does not respect the horizontality of the radiator headers;
  • Lack of automatic air bleeding;
  • Rust clogging of internal passages in radiators;
  • low pressure in the hot water pipes.
  • Tactilely feel the cold parts of the radiator surface;
  • The temperature in the room is dropping;
  • In autonomous heating systems, an increase in fuel consumption becomes noticeable;
  • In the radiators can be heard bubbling and gurgling coolant.

How to deflate the air from the radiator. easy and simple!

The cold weather has come, and in every home the heating system has been working for a long time. Modern radiators are so convenient and practical that many have already forgotten how they could heat their homes without small, compact and convenient batteries. But even heating has its disadvantages. The first is very dry air, which can be humidified with a special humidifier on the battery. The second there are many technical issues, one of which we will discuss today.

How to bleed your radiator | Solved on screen

Types of Bleeding Mechanisms

Battery valve

Known mechanisms used to bleed air from heating systems, it is customary to divide into manual and automatic. Manual devices (or Maevsky cocks) are small in size and normally installed on the end face of the radiator. Managing the valve to bleed air by using a special key, a simple screwdriver, and sometimes manually.

A flathead screwdriver can be used

Bleeding air by means of a Mayevsky valve should be made after the cool-down of the coolant in the system (t. е. when the batteries are cold). Due to their small size, the devices are not very efficient and are used usually only for the elimination of local faults.


Automatic air diverters are used in heating systems of the closed type and work without direct human intervention. Having high efficiency they are rather sensitive to impurities in the heat carrier and are installed together with the filters installed both in the supply and in the return branch of the heating system.

To improve the efficiency of automatic bleeding systems, they are made multi-stage, which provides the possibility of separate air discharge in each group of devices. If the pipes are installed with a slight slope in the direction of water movement. bleeding them accompanied by an increased flow of coolant, which leads, as a rule, a gradual increase in pressure in the system.

Remove the air lock without draining the water

You probably know how to remove air from the heating system by standard methods. Having found the unheated radiator you must open the Mayevsky tap with a screwdriver and let the air bubble out. If old batteries are installed, where there is no such valve, you can try to remove by other means:

  • The so-called pumping of the pipe network is used in apartments in multi-storey buildings provided that the radiator has a tap to release water. Connect a hose to it aimed at the drain, open the valve to the maximum and drain until the moving at a high rate of flow does not carry an air lock.
  • In a private home you can deflate Soviet steel batteries with a self-tapping screw. Wrap it around the base with FUM-tape and screw it into the wall of the heater with an electric screwdriver (close to the top). Then unscrew the screw a couple of turns with a screwdriver, let the air out and tighten until it stops. In summertime, cut in the Mayevsky valve at this point.
  • Removing air from cast iron batteries summer house, are not equipped with air, you can perform in two ways: a full refilling the system or increasing the pressure (up to 2 bar) with simultaneous heating. Unscrew the side caps “on the go” is not recommended, then they will be difficult to seal.
  • Poor circulation and heat loss can result from air accumulation in the network pump housing. Loosen the large screw installed in the end of the unit for a couple of turns. When a drop of water protrudes from under the rubber ring, tighten it back.

Tip. To avoid airlocks during operation, install vent valves on all radiators. If the thickness of the metal wall does not allow to cut 3-4 turns of thread, weld on top of the barrel with a hole of the required diameter. In cast iron “accordion” valve is embedded in the side of the steel plug.

Focus with self-tapping screw is also used successfully for incorrectly designed lines with upward or downward facing hinges (e.g. for bypassing doors and other building structures). How to remove the air bubble in the unfavorable place of the pipeline by screwing a self-tapping screw, see

Recommendation. If you are constantly blowing air out of the heating system through the batteries and can’t find the cause of the air lock, temporarily put automatic valves on the heaters until you figure out what’s wrong (there may be a chemical reaction with the release of oxygen).

How to bleed air from the radiator with a Mayevsky faucet

Such a device can be found on top of the radiator, which is used in almost every modern home. No expensive tools are required to open the faucet. There is no need to shut off the entire riser beforehand, as well as to wait until the coolant cools down completely.

Such manipulations are a waste of time, and the effectiveness of subsequent actions will be reduced, since the pressure indicator inside the system will be significantly reduced.

bleed, radiator, correctly
Approximate course of action:
1. A basin or any other container should be placed under the selected battery.
2. On the air vent should be placed a few rags. After the liquid is absorbed, it will begin to flow smoothly.
3. Using a wrench, carefully and slowly unscrew the valve by holding the plastic handle. A hissing or whistling sound indicates that the air is being expelled.
4. The stream of water should begin to flow evenly. This will penetrate the plug of air. Should not take more than 10 minutes. Specialists will drain up to two buckets of coolant.
5. Close the valve that is being used firmly.

For more information about deflating in this way you can see

Draining the air from the heating radiators

Before you bleed air from the radiator and from the system, you need to familiarize yourself with the features of this procedure and prepare the tools and materials. It is important to understand how to bleed the air from the radiator correctly. Need to have a special wrench that will help open the air valve on the radiator. The radiator wrench is best for this job. you can buy it in a hardware store.

If you have to work with a modern battery, then a simple screwdriver will do. You should also have a container to drain the coolant and some rags ready in case of an emergency.

Instructions on how to properly vent the radiator:

  • First inspect the radiator and find the small valve (Maevsky valve). It is located in the upper part of the device, sometimes there are several such devices.
  • Unscrew the faucet until you hear a hiss of air. Act carefully and smoothly.
  • Place a container under the valve.
  • Wait until all accumulated air has been blown out. This is evidenced by a thin trickle of water that has stopped bubbling. According to some experts, it is necessary to drain about 2. 3 buckets after the coolant begins to flow without gas. This is necessary to reinsurance not to repeat this procedure.
  • The valve is screwed back in.

In addition to the Maevsky cocks, you can bleed air from the battery with the help of automated air vents. They are intended for heating systems and remove the plugs themselves.

These devices are compact and reliable, but you must exercise caution, because the valves are unattended, and even a minor violation of the process can lead to flooding the basement or attic.

Sometimes there are situations when during the installation of the heating system have not been installed special products designed to remove the air s. To release excess air from the device requires a gas or adjustable wrench to unscrew the plug.

Bleeding Air from your Radiator. Climate DC

This work should be done slowly. If the plug is not unscrewed, and such situations often occur with cast iron radiators, a special grease should be applied to the threads. After a while the attempt is repeated. After you managed to unscrew the plug, act exactly the same as with a normal faucet.

At the end of the work the plug is returned to its place, not forgetting to wrap the thread with tape or FUM tape, which will prevent leaks and provide leak tightness of the connection.

If the air has accumulated in the heating system of a private house, the coolant is drained by the expansion tank. This container is located at the highest point of the heat supply structure. After draining the water you need to wait a while, then unscrew the tap on the tank.

As a rule, when the temperature in the battery rises, the air lock is removed on its own. If the actions performed ended without result, the water in the heating circuit must be brought to a boil, and then the air will certainly come out.

How To Bleed A Radiator. Don’t try it until you watch this

Knowing how to bleed the air from the heating battery and the system, you can avoid many problems. As a preventive measure, such a procedure should be carried out before the heating period. According to experts, two times (to check and control) will be enough. If the construction is defective or broken, the number of descents may be more.

If your apartment has aluminum radiators, you should drain the water before starting the heating system, which will increase the service life of the devices many times over.

What is the danger of air accumulated in the heating system?

If the battery is not heating properly, and from it comes bubbling and hissing, most likely there is oxygen in the system. The danger of an air lock is that it leads to corrosion and after a while can damage the entire heating system. Air enters the system for a variety of reasons, it may be a mistake during installation or filling the entire system with water, or it may be bad water, which contains oxygen in the form of impurities or bubbles.

How to deflate the cast iron battery

Many owners of private houses and apartments are familiar with the situation when the bottom or the whole radiator is cold, while the supply pipe from the riser pipe is hot. The reason for such a difference is the air lock, preventing the passage of the coolant. In new radiators to bleed air installed cocks Maevsky, which can not be said of older models. In this regard let’s analyze how to bleed air from the cast-iron battery.

Ways to remove the air lock

Since one or more of these factors may be present in many homes, the issue of removing air in the heating system necessarily arises. This operation can be performed in different ways. It all depends on what kind of coolant circulation we are dealing with. natural or forced.

In a heating system with natural circulation (meaning the upper distribution of pipes) the air lock can be removed through the expansion tank. it is located at the highest point in relation to the entire system.The laying of the supply pipe should be made with the rise to the expansion tank. In case of the lower distribution of pipes the air is evacuated in the same way as in heating systems with a circulation pump.

To bleed air from the heating system with natural circulation you can use the expansion tank

In heating systems with forced circulation of the coolant in the highest point an air collector is installed, specially provided for bleeding. In this case, the supply pipeline is laid with the rise in the course of the coolant, and rising air bubbles on the riser is removed through the air cocks (they are installed at the highest points). In all cases the return pipe must be laid with an inclination towards the direction of water drainage for faster emptying in case of repair.



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