Expansion tank for water - the basis of the effective operation of the heating system

Expansion tank for water supply

In the cold season, when the outside cold anddamp when you want comfort and warmth, is particularly important to have a good heating and water supply system. And in order not to falter in their work, it is necessary in advance to pay attention to such an important element as an expansion tank for the water supply. It is up to its technical condition depends on the reliability and durability of the life-supporting systems.


  • Types of expansion tanks for water supply and heating
  • Features selection of expansion vessel
  • What is the working principle?
  • The main emphasis during installation

Types of expansion tanks for water supply and heating

Expansion tanks are inherent attributes of boosting water systems, heating systems, as well as fire extinguishing systems. They are distinguished two basic types:

  • Expansion tank Open Type. Is a tank at the bottom whichIt has connection with the heating pipe. Characterized by the dependence of the water level therein the total volume of liquid in the system. The higher the water temperature the greater the rate of its volume. The tank is located at the highest point of the heating system, usually the attic of the building. To reduce heat loss through the walls of its container insulate. Open the expansion tank is leaking, neestetichen, cumbersome, so it is not suitable for placement in the room.
  • Expansion tank closed type or a diaphragm expansion tank. It is a sealed metal capsule-capacity, having an oval or spherical shape. Inside it divides membrane made of heat resistant rubber. As a result of this form two chambers - liquid and air. Inside, the air separation installed valve for deflation (deflating) the air at the time of a strong pressure increase. Thus, the liquid occupies the internal volume of the tank.

Features selection of expansion vessel

In order to make the correct selection of the expansion tank, you must know exactly the total amount of coolant.

In addition, his choice should be based on strict conformity maximum permissible boundaries of range of pressures in the heating system.

Expansion tank membrane type

The design of the expansion tank membrane type

One should know that alleged overstatementthe volume of the surge tank at its operating parameters, as well as the functioning of the heating system as a whole does not influence. Finally, the choice should calculate the expansion tank based on the fact that the coolant is given a limited amount inside the tank. A primary surplus above and the maximum value of the pressure, taking into account corresponding to each of these factors determine the largest part of the total volume of the expansion tank that dedicated to the coolant.

It is important to know! Operation of the tank, characterized by understated the volume of water invariably entail negative consequences. Obviously, its use at the time of maximum thermal stress, that is, when the system pressure approaches the maximum permissible values, will result in leakage of coolant in the field of threaded connections tank or cracking. Expansion tank for heating used in the operation of the system at low heat loads will cause a reduction in pressure in the system and consequently reduce the coolant volume. As a result, atmospheric air seeping into the container.

Typically, membrane-type tanks are manufactureda non-removable membrane, which is rigidly fixed to the cross section of the tank. The outer surface of the container is covered with enamel red, and the inner cavity directly in contact with the medium, ie the coolant - a special moisture-resistant paint.

It is worth paying attention! Unfortunately, there is no universal material for the manufacture of membranes. But still in the process of selection of the tank is necessary to pay attention to the type and quality of the membrane.

Any such membrane has performance characteristics:

  • Operating temperature range;
  • hygiene requirements;
  • durability;
  • dynamics of the system;
  • resistance to water diffusion.

What is the working principle?

If we analyze the working principleExpansion tank belonging to the membrane type, it is as follows: heated in a closed loop coolant expands when the volume increase reaches the tank capacity, the membrane is stretched, thereby reducing the proportion of similar piston airspace (i.e. compressed air). During this period the pressure vessel to the expansion vessel and, consequently, the whole system is increased. When the water temperature decreases, its volume is reduced in the heating system. Furthermore, the pressure is reduced and, therefore, the water previously adopted by the compressed air is pushed back into the system.

It is important to know! Before you install an expansion tank in your own home, even at the stage of selection should make sure in the presence of a certificate of quality, and in some cases, the security certificate. It is in this case, you can be sure that the heating system selected item will be a reliable and functional.

If there is a slight leakage of liquid,and the pressure in the system and falls in the expansion tank and the compressed air pushes the water reserve volume, thus heating occurs makeup. The initial stage of operation of the heating system involves the circumstances in which the coolant pressure is to some extent larger than the hydrostatic pressure of the system. For this reason, the liquid chamber takes the coolant expansion tank in a quantity corresponding to operational losses. By increasing the capacity of the liquid chamber volume decreases and pressure increases the volume of air in the tank chamber. Thus, the steady pressure is the initial operating pressure of the heating system.

Expansion tank for water supply and heating systems

Now one can easily pick up the expansion tank with the required volume

The main emphasis during installation

Of course, the installation of the expansion vessel requires a professionally drawn up by the project, as well as installation instructions.

Initially the gas tank supplied with fillingthe entire internal volume and is under positive pressure. Just before performing assembly work on the pressure tank is charged, the value of which is calculated beforehand.

Installing the expansion vessel is accompanied by the following features:

  1. Capacity, the volume of which exceeds 500 liters, can not get through a standard doorway.
  2. Do not mount the non-return valves and filters on a branch connecting the expansion tank and heating system.
  3. Connecting the expansion vessel shouldbe subject to a further service. And it requires the installation of stop valves for the branch to the tank and in such a way as to prevent accidental closure.
  4. The pipe: cut-off valve, tube tank must be equipped with a drain cock.
  5. In close proximity to the place of installation wiring diagram of the expansion tank should involve the installation of a pressure gauge and a safety valve.

Expansion tanks for heating systems usuallymean heat capacity of up to 6 MW. If the operation of the heating means more powerful systems, due to constant water leakage is required to ensure the smooth operation of clock feeding pumps.

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