As you know from the school physics course, fluid expands when heated. 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 rupture of radiators and highways. If you do not find a way to remove the excess volume of water, the entire system can easily fail in just a few hours. To do this, additional communications are installed, allowing to accumulate pressure in the expansion tank of the closed heating type.
Principle of operation
Without this auxiliary equipment, no normal heating system is possible. The simplest devices make it possible to compensate for the expansion of the heated fluid and to avoid water hammer. For this reason, it is imperative to observe the safety rules during use. It is quite simple to select the necessary unit and carry out installation. With the right choice of equipment, long-term stable operation of the entire heating system will be guaranteed.
Tank selection
When designing a reliable heating system, everyone will have to reasonably choose such a tank and mount it in the heating system. The characteristics of the device will depend on the functions performed and the type of structure being installed. Only three options are available on the market.
Expansion tank for closed heating . The price of such units in the domestic market can vary from 2500 to 75 000 rubles, depending on the required volume. An ordinary sealed tank is filled with air. With increasing pressure in the system, the tank space is filled by compressing air. A special membrane is installed in the inner part of the tank. It is necessary to protect the unit from rust after increasing the corrosive activity of water as a result of mixing with oxygen.
An open tank does not have a sealed lid. The average cost in the domestic market is about 3,000 rubles. Such devices are used not only to compensate for expansion, but also to remove air jams from the system. A coolant can be added to the structure 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 vent water from a home heating system as quickly as possible.
Installation Instructions
The installation of expansion tanks should be carried out in strict accordance with the technology for the highest quality operation of heating devices. The device must be installed above the boiler, and the water pipes should be directed downward for the convenience of draining the coolant in case of breakdown of the membrane.
Such a system is based on forced circulation of energy carriers, so it must be compensated by circulation pumps. It is much more difficult to choose and install a flat expansion tank for closed-type heating when compared with other types of devices, since they are not designed to compensate for thermal expansion. The stable operation of the entire system will depend on the quality of the installation.
Such tanks are installed in areas where there are no turbulences during the coolant flow. For this reason, it will be correct to place on straight sections of pipelines in front of the circulation pumps. You will have to familiarize yourself with some general rules for the selection and installation of tanks, which must be followed when designing and assembling the system.
Volume calculation
A tenth of the coolant passing through the system should be placed in the tank. In no case should you choose a smaller size, because the pressure in the expansion tank of a closed type heating system will be too high, and hydraulic fracturing cannot be prevented. Such a calculation is suitable only in cases where water is used as a coolant. It is necessary to choose a larger volume of the tank if ethylene glycol circulates in the system.
Such an expansion tank must be equipped with a special safety valve. Almost always, it is included in the factory kit. If the valve is not provided for the tank, you must buy it and install it. The pressure in the expansion tank of a closed type heating can be reduced thanks to such a device.
If the calculation was carried out incorrectly, and an aggregate with insufficient volume was purchased, you can buy another one. Frequent increase in pressure in heating systems will be a clear sign of a mistake when choosing a tank.
Accommodation
The height of the installation of the tank from the floor will not play any role. Tightness will be maintained, and air will be discharged through special valves. During installation, it is advisable to consider that the flow of coolant from above will be the most optimal option. This makes it possible to get rid of air entering the compartments for liquids.
When an expansion tank for heating a closed type is selected, the price of the entire system may turn out to be higher when compared with the option of purchasing double-circuit electric or gas boilers, in which a mechanism for lowering the pressure is already provided.
Suitable amount of water
In heating systems, the required volume of water is determined depending on the size of the room, the capacity of the boiler and the number of heating elements. In conventional systems, 14 liters are calculated per 1 kW of voltage. Such an amount should be sufficient for good circulation and normal heat transfer.
Calculation Methods
It is not always easy to choose a suitable expansion tank for closed heating. Instructions for installing a room heating system can sometimes be carried out only thanks to outside help. Each owner can use several available ways to choose the right tank. The easiest way is to find a special calculator program on the Internet that facilitates the calculation of the specified parameters and makes it possible to determine the size of the tank to fully compensate for excess pressure in the system.
You can also address this issue to specialists working in design bureaus. This is the most reliable and most expensive option. Thanks to this method, it is possible to avoid design errors and prepare it for stable continuous operation.
Some try to calculate the required tank volume using the formulas themselves. At the same time, it is necessary to take into account how much pressure in the expansion tank of a closed type heating can change. The coefficient of volume increase at a coolant temperature of 95 degrees is 0.04, and at 85 ° C - 0.034. Specialized programs make it possible to carry out calculations based on the total volume of water in the system, calculated by the power of heating boilers.
Exact calculations determine the overall heating efficiency, ensuring uninterrupted operation, eliminating possible malfunctions in case of violations during operation of the equipment.
Recommendations of specialists
The maximum permissible pressure in the expansion tank of a closed type heating is determined by the threshold values of the safety valves. It is desirable that they can be regulated. Tank volumes are initially selected with a margin so that they can perform all the necessary functions with inaccuracies in the calculations without creating a threat of accidents. You should not save on purchase, and it is preferable to trust the installation of all equipment only to professionals.
Do not forget that the reliability of the heating system will depend on the level of protection of the house from the cold, since any malfunctions can leave the building without heat completely. Proper installation makes it possible to avoid many problems, and any house will be protected during the most severe cold weather. Naturally, over time, each expansion tank for closed heating can be damaged. Malfunctions in the operation of the heating system arise from time to time. To resolve all problems, it is best to contact qualified professionals for help.
Membrane tank for closed heating
This type of equipment is divided by rubber partitions. Air is pumped into the upper part to supply initial pressure. The coolant flows into the lower part, and the heating installation starts. With increasing temperature, the amount of water increases, and its excess is released into the tank. When the coolant returns to its original volume in the heating system, automatic pressure control takes place. The membrane in this case assumes its usual position.
Tank Mounting Tanks
Such equipment makes it possible to regulate the pressure more accurately. The air chamber is located around the entire perimeter of the tank. The rubber compartment expands when the 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 standards and specific requirements for elasticity, heat resistance, duration of possible operation, moisture resistance.
Conclusion
The heating installation must always be equipped with an expansion tank. This equipment is designed to maintain a stable and constant pressure, ensuring the normal functioning and proper operation of closed systems and the circulation of coolant in them.
The main objective of such tanks is to reduce the possibility of fracturing due to a sharp increase in pressure in the pipes. This can lead to malfunctioning of individual elements of the heating system.