To heat country houses in our country, autonomous heating systems are often used. They are quite structurally complex communications, in addition to the boiler and radiators, which include many other elements. For example, in such networks, an expansion tank is installed next to the heat generator. For a closed heating system, the volume of such a compensation tank must be calculated without fail. Otherwise, the expansion tank will not cope with its functions.
What is a closed heating system
It is these networks that are most often used today for heating country houses. Closed heating systems differ from open ones with the type of installed expansion tank. This element of home networks is mounted at the highest point and is responsible for stabilizing the pressure of the coolant in the pipes.
When heated above +4 ° C, water, as you know, begins to expand. The same thing happens with it with strong cooling. Therefore, the pressure in the heating pipes is inconsistent. With the expansion of the coolant, the pipe can simply break. In order to prevent this from happening, an expansion tank is mounted on the network. With an increase in the volume of coolant, its excess simply goes into it.
Types of expansion tanks in home heating networks can be used different. If this device has an open design, the system, accordingly, is called open. If the expansion tank on the trunk is mounted tight, the network is called closed.
Benefits
The main advantage of a closed expansion tank in the heating system is that, if available, the circulation pump can also be included in the design of the latter. This allows you to make an autonomous network much more productive and easy to use. In addition, the structural elements of such heating systems do not spoil the appearance of the premises of the house. Pipes to the boiler in this case are connected thin.
In open systems, water moves along highways by gravity - under the influence of gravitational forces. Such networks are considered non-volatile. However, when installing them around the house, thick pipes are laid, which, of course, negatively affects the appearance of the premises. In addition, such heating systems can not be installed in buildings of a large area. Today, mostly large private houses are being built outside the city.
Types of expansion tanks
Installation of structural elements of a heating system of this type must be carried out correctly. Only in this case, the network will ultimately turn out to be reliable, easy to use and will last a long time. And first of all, for a closed heating system, of course, you need to choose the right expansion tank.
First of all, one should purchase such a device, designed specifically for heating systems. Such tanks are red. On sale today there are also blue compensation tanks designed for hot water pipes. Such a tank for a home network used for space heating will not work.
There are three main types of expansion tanks for closed heating systems on sale today:
Membrane tanks
Such containers, in turn, are today delivered to the market in two versions:
Both of these types of membrane tanks have similar technical and operational characteristics. The difference between them is only that the volume of the expansion tank for the closed heating system of the latter variety is slightly larger. Accordingly, it contains more coolant.
The membrane itself in the tanks of both varieties is shaped like a pear. On the opposite side, air or nitrogen is pumped into such an expansion vessel under some pressure.
Such tanks work according to a very simple principle. With increasing pressure in the network, the membrane of the tank stretches and launches water into it. When pressure drops, everything happens in the reverse order.
Built-in tanks
Such containers are commonly used with wall mounted gas boilers. Expansion tanks are most often included directly in the design of such heating units. The advantage of containers of this type is primarily considered the complete lack of contact with the external environment. Diffusion of oxygen into the coolant in the presence of such a tank cannot occur.
A certain drawback of this type of reservoir is the not too long membrane life. It usually becomes unusable after 10 years of operation. At the same time, it is not always possible to replace its ability.
Vacuum containers
Compensatory constructions of this type are distinguished by the fact that they do not have pears inside. The role of the membrane in them is played by the air itself. Such tanks are used very rarely in home heating systems. The fact is that they are almost impossible to find on sale. In addition, such tanks are also not considered too convenient to operate and reliable.
Calculation of the volume of the expansion tank of the heating system
To select an expansion tank for the heating system is, of course, necessary, not only in design, but also focusing on its volume. Before buying such a compensation device, it is mandatory to make its calculation.
There are several methods for determining the required volume of the expansion tank for the heating system. But with the independent installation of such networks in small houses, property owners usually use simplified technology.
Based on the laws of physics, experts established the fact that with maximum heating, the water in the mains of home heating networks expands by about 5%. Accordingly, the required volume of the expansion tank for a closed heating system can be calculated as follows:
in accordance with the passport of the heat generator determine the amount of coolant in the pipes;
find an indicator of pipe throughput (by multiplying the cross-sectional area by length);
determine the amount of water in the radiators from their passport;
summarize all three values found.
When using this technique, the tank is selected with a margin of not 5% of the result, but just in case 10%.
Where to install
After the volume of the expansion tank for the closed heating system is determined, and this device itself is purchased, the owners of the country house will need to choose the most suitable installation location for it.
Such capacity should be mounted, as already mentioned, at the highest point in the system. Currently, expansion tanks in most cases are installed directly in the boiler room next to the heating unit.
Such devices are usually mounted on the return pipe in front of the pump (in order to exclude water hammer). In principle, the supply is also a suitable place to install a closed expansion tank for the heating system. The amount of coolant in such networks is usually uniform. But, since the temperature of the supply water is significant, a container mounted in this way will serve here in the future, most likely not for too long.
Installation Tips
Experienced craftsmen recommend inserting the compensation capacity into the heating system through a flange or screw-in connection. In this case, the subsequent tank can be easily removed for repair.
Filters or non-return valves must not be mounted on the branch that connects the tank to the line. When choosing a place for installing the tank, experts also recommend making sure that it is located here completely free. No pressure from the structural elements of the heating system or anything else should be exerted on it.
A closed expansion tank will function, although lying on its side. But to embed it in the heating system, of course, is better vertically.
Installing the expansion tank in the heating system: installation steps
Insert the expansion tank into the system, usually as follows:
the container is securely fixed on the floor or on the wall;
outline the shortest route for the pipe to the point of connection;
pull the pipe and connect the tank.
Among other things, a simple inexpensive ball valve is usually installed on the eyeliner to the tank. This allows you to cut off the tank from the system at any time and drain the water from it.