Valve for bleeding air from the heating system

Why is the air in the heating system dangerous?

When air appears in the heating system, a plug is formed. Because of this, one part of the pipeline remains cold, and the other too overheats. When air accumulates from all heating circuits in one place, the movement of the coolant completely stops. What does it threaten:

When an air blockage appears in a closed loop, pressure builds up in the system. This triggers the safety valve.
It will constantly work and remove water from the system until the heating equipment burns out.
Sometimes, this pressure will rupture pipes.

To prevent this and eliminate the problem, an air vent is installed. In addition to these difficulties, the presence of air in the circuit will lead to oxidation of the pipe, the occurrence of rust and a decrease in the service life.

Reasons for the appearance of air in the system

Air accumulations inside the heating circuit can appear for various reasons:

Primary water filling.
Suction through poor quality gaskets.
Water make-up.

Most often, the gas comes from the water itself, which contains a large amount of dissolved oxygen. An increase in temperature, a slowdown in movement speed, and a drop in pressure reduce its solubility. This provokes the release of air into the atmosphere, which explains the need for a mandatory procedure to remove plugs from the heating system.

After release, the air begins to move upward, focusing on areas with difficult passage. As a result, air pockets appear there, creating problems for the normal circulation of the coolant. To neutralize these plugs, valves are used to bleed air from the heating system. The place of their installation is certain sections of the contour.

Purpose and types of air vents

The air vent is designed to discharge air from the heating system and to avoid the appearance of air pockets. Air accumulation occurs during system operation or due to malfunctions. Sometimes this happens when the pipeline is filled with a coolant or when there is a loss of tightness in one of the mechanisms. There are 2 types of air vents, which differ from each other in design features:

Mayevsky's hand cranes;
automatic air valves.

Each device consists of a shell and a valve. The body has a threaded connection and a gasket, thanks to which it is attached to any part of the heating system. The outlet port is closed by a valve, which consists of a rubber gasket or is in the form of a cone. Depending on the model, the valve can operate in either automatic or manual mode.

Each product is suitable for installation anywhere in the system and works the same way. Solenoid valves for air have a straight and angle configuration, and Mayevsky's taps are made in a radiator and simple design.

What are air valves?

The air valve for heating is a cylindrical sealed brass body. Inside the robust shell is a hollow polypropylene or Teflon float connected by a lever to a bleed valve fitted with a shut-off plug. The plug cap is needed to prevent leakage of the coolant in the event of a device breakdown.

Important! Normal functionality of the air receiver for the heating system is only possible with a fully open plug.Closed cap to protect the float from debris and dust. Putting the valve into operation involves twisting the cap.

There are three types of relief devices:

devices are straight only for vertical mounting;
angular, they can be placed at a right angle instead of Mayevsky's cranes, if it is not possible to integrate a direct device;
special dumpers for mounting on batteries.

The principle of operation is determined by the type of product - manual (Mayevsky cranes) and automatic float type.

Weather thermostat for heating boiler regulation

Features of the operation of manual valves

The mechanical or manual air vent of the heating system is characterized by the simplicity of the device and is a brass body with an external thread and an end hole of 2 mm, which covers the screw with a tapered tip. There is a reduced size hole on the side of the body for venting gases. The drawings show that Mayevsky's crane is a simple but durable and functional device that is difficult to break, which is why manual valves are popular.

On a note! In order not to twist the valve, it is necessary to choose an improved version of the drain with a rotary plastic insert with a branch channel. A plastic washer is turned to adjust the position of the vent hole.

Principle of operation:

During the operation of the system, the valve is tightly twisted, the hole is closed with a sealed cone.
To release the plug, unscrew the screw 2-3 turns. The pressure acts on the gases, forcing them to escape from the opening, from where the air enters the exhaust duct and out.
The end of the bleeding process is the exit of the coolant jet without gas bubbles.

A mechanical valve is installed only on radiators. According to the method of unscrewing, the manual air vent can be with a plastic / metal handle, a pin for a flat screwdriver, or equipped with a screw with a four-sided tip - for such devices you need a special key.

How automatic valves work

By installing these devices, the owner can no longer take part in adjusting the system. The automatic valve for venting air from the heating system is a brass float type device. The valve itself is built into the cover, connected to the float by a spring lever, the thread on the cylinder can be 1.5 or 0.375 inches. If the heating system has old-style radiators, then an inch and a half product will do.

The principle of operation of an automatic air vent in the heating system is as follows:

As soon as the line is put into operation, the inner chamber of the cylinder is filled with water. The liquid raises the float, the valve is pressed by a spring and therefore hermetically closed.
The formation of an air lock in the upper section of the chamber leads to a decrease in the level of the filler in the line and the spring relaxes.
Loosening of the spring mechanism opens the valve, gases are released. The pressure in the system rises, the water level increases, and due to this, all the air from the circuit is vented. As the fill level rises, the spring presses the valve firmly again.

On a note! While the line is being filled with coolant, the float lies at the bottom of the chamber and the air is constantly vented. As soon as the circuits are filled, water enters the chamber, the spring raises the valve - the release of the contents stops. The air under the cover does not interfere with the operation of the system.

Types and production of pressed peat fuel briquettes

Automatic products can be of a straight type, discharging air to the side, and angular type, discharging gases vertically. Corner devices are durable and reliable, but they collect small air bubbles worse.

Where are the air release valves installed?

In open-type heating systems, air escapes through the expansion tank. But if the system is equipped with a pump for forced circulation of the coolant, then there is a possibility of air congestion. Therefore, in such systems, a manual or automatic air release device is installed. Installation locations of air vents, depending on different situations:

On radiators, it is customary to install a manual valve for air relief. It is mounted in this place because airing most often occurs at this point of the heating area. Therefore, they try to equip all radiators with devices.
In the upper sections of the vertical risers (where bubbles are trying to penetrate), automatic devices of the direct type are installed. These are the most popular models, they are also mounted on underfloor heating collectors.
If air has accumulated in a hard-to-reach place, such as the ends of dead-end branches, then corner and radiator models are used. The valve is connected to the system by means of a pipe.
If the design of the circulation pump provides for the installation of an air vent, then it is mounted in order to improve the performance of the device. The airborne coolant is more difficult to pump over and slows down its operation. Because of this, it often stops, which leads to rapid wear of the bearings and impeller.

Corner and radiator air vents

In different heating systems, many situations can arise when it is necessary to remove air locks in the most difficult or remote places. It is impossible to list all of them, since there are too many options. Where it is not possible to install a simple valve because the threaded end pipe is horizontal, an angled air vent is suitable. Its branch pipe, coming out from the bottom, turns at an angle of 90º and can be connected to the horizontal section.

It should be noted that an angled air vent with an external threaded connection does not differ from a conventional straight valve in anything other than a rotated branch pipe and can be used instead of it if necessary.

Often, to automatically bleed air from the batteries, instead of the traditional Mayevsky tap, some users install an angle valve. This is true in an unpleasant combination of circumstances, when gases are formed in the network constantly and this happens just in the radiators. The reason is the chemical reaction of substances sometimes present in water with an aluminum alloy of batteries at an elevated temperature. It makes no sense to install a valve with an angle pipe, because there is a special automatic air vent for radiators, shown in the photo:

These devices are designed for batteries only and have a suitable threaded connection. Instead of manual taps, it is preferable to put them on heaters made of aluminum or partially bimetallic, where there is also contact between the alloy and water. In other situations, the radiator air vent is mounted at will, but the fact that it will bring convenience in operation is beyond doubt.

Note. It is better to equip traditional cast-iron batteries included in the centralized heat supply network with a Mayevsky manual tap and a drain pipe.

For ease of maintenance and cleaning, complete devices are available for sale - automatic air vents with a valve. The latter is a small threaded adapter with a spring-loaded petal valve inside. The adapter is screwed onto the thread directly in front of the air vent and serves so that, with the system in operation, it can be removed and cleaned or replaced. Air vents from DANFOSS, VALTEK and many other well-known brands are supplied with similar adapters.

How to choose and install an air valve for heating?

Experts advise buying quality products from trusted suppliers, not cheap Chinese products. Air valve selection:

products equipped with a shut-off valve are the best because they can be easily removed and replaced;
in order not to use screwdrivers and keys, the Mayevsky crane is chosen with a handle;
the best are those models that are equipped with additional functions;
products covered with anodized protection are not subject to oxidation.

But before buying an air relief valve, you need to familiarize yourself with the technical characteristics of the heating equipment. For a two-story house, devices with an operating temperature of 100 ° C are used. They work efficiently at a pressure of 0.5-7 bar. Valve installation:

The automatic air bleed device is mounted vertically on the radiators. In this case, the cap that closes the outlet is directed upward. This arrangement is used for straight and angled models.
The ball valve is mounted in front of the drain valve. This is a prerequisite, thanks to which the air vent can be removed at any time without draining the water. Sometimes a shut-off valve is installed instead of a ball valve.
Installation of the Mayevsky crane is carried out with a wrench. Unlike an adjustable wrench, this tool makes it easier to track the tightening level of a fastener. To prevent the device from breaking during screwing, it is held by the hexagon located under the camera, and not by the body.

If air accumulates in a multi-storey building after replacing the radiators, then the air vent is mounted on each radiator located in the upper manifold.

Valve installation location

There are points in the heating system where air is necessarily collected. So, Mayevsky's taps in the apartment should be installed on each radiator. In many modern radiator models, air bleed devices are installed at the manufacturing stage by the manufacturers themselves.

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Note! If you have classic radiators, then the air valve should be installed in the upper part of it, which is located opposite the connection.

So you can always independently control the normal operation of your heating batteries and not depend on the desire of the housing office employees or the mood of the neighbors from above.

Points for installing air relief valves:

radiators, bathroom coil, upper part;
the top point of the pipeline;
heating boiler safety system in individual communications;
for hydraulic branching;
on the collectors of the common manifold;
on any U-shaped loops in communications, at the top point;
for expansion joints in plastic heating systems.

It should be understood that air always accumulates in the upper part of the communications. An air lock can arise in the bend of a plastic pipe if the installation was carried out incorrectly and there was a temperature deformation.

The easiest way to get rid of the plug in the pipeline permanently is to cut a tee into the pipe. On the free vertical branch of the tee (the diameter of which is selected accordingly), a valve is installed to release air.

How to get rid of an airlock?

Sometimes, due to improper pipe laying and illiterate engineering design, air locks appear in hard-to-reach places. It is difficult to remove air from there. Air bleeding process:

You can determine the location of the plug by the murmur and cold section of the pipe. If these signs are absent, then the pipes are tapped. A loud and loud sound indicates an accumulation of air.
In a private house, air cushions are expelled from the pipes by increasing the temperature or pressure. To do this, open the drain valve closest to the jam and the make-up valve. The coolant will fill the pipes, the pressure will rise, the plug will begin to move and exit through the valve. After all the air has escaped, the hissing will stop and the water pressure can be shut off.
If the plug remains, then it is necessary to raise the temperature and pressure at the same time. The indicators are raised to the maximum level (do not exceed it, since it is dangerous).

If designed incorrectly, the problem will appear regularly and in the same place. To remove it, an air vent is connected to this place. For large highways, a tee is mounted. A valve is mounted on a free entrance.