Pressure in the expansion tank of the closed type: instructions, principle of operation

As is known from the school course of physics, the liquid, when heated, expands in volume. Since in heating systems the elasticity of the pipes is not so high as to accommodate the increased volume, the pressure rises sharply. This often leads to the rupture of radiators and highways. If you do not find a way to remove excess water, the entire system can easily fail in just a few hours. For this purpose, additional communications are installed that allow the accumulation of pressure in the expansion tank of closed type heating.

Principle of operation

Without this auxiliary equipment, the normal operation of a single room heating system is impossible. The simplest devices make it possible to compensate for the expansion of the heated liquid and avoid a water hammer. For this reason, you must always follow the safety rules during use. To pick up the necessary unit and to spend installation is simple enough. With the right choice of equipment, the long-term stable operation of the entire heating system will be guaranteed.

Selecting a container

When designing a reliable heating system, everyone should reasonably choose such a tank and install it in a heating system. The characteristics of the device will depend on the functions to be performed and the type of structure to be installed. There are only three possible options on the market.

Expansion tank for heating of closed type. The price for such units in the domestic market can vary from 2500 to 75 000 rubles, depending on the required volume. An ordinary hermetic tank is filled with air. When the pressure in the system increases, the space of the tank is filled by means of air compression. In the inner part of the tank is installed a special membrane. It is necessary to protect the unit from rust after increasing the corrosive activity of water as a result of mixing with oxygen.

The open tank does not have a sealed cover. The average cost in the domestic market is about 3000 rubles. Such devices are used not only to compensate for expansion, but also to remove air plugs from the system. In the design, a coolant can be added through such a tank to compensate for its gradual evaporation.

Water heating at home can be designed using a tank with top filling. This is a sealed container equipped with a valve. With the help of such a tank, it is possible to discharge water from the home heating system as quickly as possible.

Installation Instructions

Installation of the expansion tanks must be carried out in strict accordance with the technology for the most qualitative work of the heating devices. The device must be installed above the boiler, and the water pipes must be directed downwards for the convenience of draining the coolant in the event of a breakdown of the membrane.

Such a system is based on forced circulation of energy carriers, so it must be compensated by circulating pumps. A flat expansion tank for closed type heating can be chosen and installed much more difficult when compared with other types of devices, since they are not intended to compensate for the temperature expansion. The stable operation of the entire system will depend on the quality of the installation carried out.

These tanks are installed in areas where there are no vortices in the flow of the coolant. For this reason, the correct variant will be the location on the straight sections of the pipelines in front of the circulation pumps. You will need to familiarize yourself with some general rules for the selection and installation of tanks, which must be observed when designing and assembling the system.

Calculation of volume

A tenth of the coolant passing through the system should be placed in the reservoir. A smaller size can not be chosen in any case, because the pressure in the expansion tank of the closed type will be too high, and it will not be possible to prevent the fracturing. This calculation is suitable only in cases where water is used as a coolant. You need to choose a larger capacity if ethylene glycol is circulating in the system.

Such a surge tank must be equipped with a special safety valve. Almost always he comes in the factory kit. If the valve at the tank is not provided, it is necessary to buy it and install it. The pressure in the expansion tank of closed type can be reduced by such a device.

If the calculation was not carried out correctly, and the unit with insufficient capacity was purchased, you can buy one more. Frequent increase of pressure in heating systems will serve as a clear indication of an error in the selection of the reservoir.

Accommodation

The height of the installation of the tank from the floor will not play any role at all. The airtightness will be maintained, and the air will escape through special valves. During installation it is advisable to take into account that the flow of coolant from above will be the most optimal option. This makes it possible to get rid of the air entering the fluid compartments.

When the expansion tank for closed type heating is selected, the price for the entire system can be higher if compared with the option of buying dual-circuit electric or gas boilers in which a mechanism for lowering the pressure is already provided.

A suitable amount of water

In heating systems, the required volume of water is determined depending on the size of the room, the boiler output and the number of heating elements. In conventional systems, 14 liters are calculated per 1 kW of voltage. This amount should be sufficient for good circulation and normal heat transfer.

Methods of calculation

It is not always easy to choose a suitable expansion tank for closed type heating. The installation instructions for the room heating system can sometimes be made only by outside help. Each owner can take advantage of several available ways of choosing the right tank. The easiest way is to find on the Internet a special calculator program that facilitates the calculation of the specified parameters and makes it possible to determine the size of the tank to fully compensate for the excess pressure in the system.

You can also refer to this question to specialists working in project offices. This is the most reliable and most expensive option. Thanks to this method, it is possible to avoid errors in the design and prepare it for stable long-term operation.

Some try to calculate the required tank volume by the formulas themselves. It is necessary to take into account the extent to which the pressure in the expansion tank of the closed type can vary. The coefficient of volume increase at a coolant temperature of 95 degrees is 0.04, and at 85 ° C it is 0.034. Specialized programs make it possible to perform calculations based on the total volume of water in the system, calculated from the capacity of the heating boilers.

Accurate calculations determine the overall efficiency of heating, ensuring uninterrupted operation, excluding possible malfunctions in the event of equipment failure.

Recommendations of specialists

The maximum permissible pressure in the expansion tank of closed type heating is determined by the threshold values of the safety valves. It is desirable that they can be regulated. The volumes of tanks are initially selected with a margin, so that they can perform all the necessary functions inaccuracies in the calculations without creating a threat of accidents. Save on the purchase should not be, and the installation of all equipment should preferably be trusted only by professionals.

Do not forget that the reliability of the heating system will depend on the level of protection of housing from the cold, as any malfunctions can leave the building without the heat completely. Proper installation makes it possible to avoid a lot of problems, and any house will be protected during the most severe cold weather. Naturally, with time, each expansion tank for heating of a closed type can be damaged. Malfunctions in the operation of the heating system occur from time to time. To solve all problems, it is better to seek help from qualified professionals.

Membrane heating tank for closed type

This type of equipment is divided by rubber partitions. In the upper part of them, air is pumped to supply the initial pressure. The coolant is supplied to the lower part, and the heating installation is started. As the temperature rises, the amount of water increases, and its excess is released into the tank. When the coolant returns to the original volume in the heating system, automatic pressure adjustment takes place. In this case, the membrane takes its usual position.

Tanks with cylinder installation

Such equipment makes it possible to regulate the pressure more accurately. The air chamber is located around the perimeter of the tank. The rubber compartment expands when a coolant enters it. The main feature of such membranes is the possibility of replacement in case of wear. Rubber material must always comply with sanitary norms and specific requirements for elasticity, heat resistance, duration of possible operation, moisture resistance.

Conclusion

The installation of the heating should always be completed with an expansion tank. This equipment is designed to maintain a stable and constant pressure that ensures the normal functioning and proper operation of closed systems and the circulation of the coolant in them.

The main task of such tanks is to reduce the possibility of hydraulic fracturing due to a sharp increase in pressure in the pipes. This can lead to malfunctions in the operation of individual elements of the heating system.