The quality of the heating system of a private house largely depends on the stability of the water supply. Even in normal operation of communication networks, pressure differences can occur. Typically, such failures occur without consequences and are invisible to the user, but there is always a risk of damage to equipment and the pipeline, and at high loads it could well turn into an accident. An accumulator for heating systems, which acts as a buffer pressure regulator, will insure against troubles of this kind.
Equipment device
At the heart of any accumulator is a container for temporary water content, which determines the second name of this equipment - an expansion tank. The tank is divided into two parts, one of which is for liquid, and the second for air. These chambers are separated by an elastic membrane, which can change position depending on the current pressure in the system and filling with water. Also, the accumulator device for heating systems does not do without an air (pneumatic) valve that takes air masses from the tank. Small tanks are supplemented by separate regulators in the form of ball valves and tees, which also allow air to be removed from the pipeline. In kits with hydraulic accumulators, manufacturers supply the necessary fittings for connecting, mounting and strapping with other plumbing and heating equipment.
Types of design of hydraulic accumulators
The parameters of the housing and the configuration of the location of the communication pipes will determine the installation conditions for the expansion tank. Fundamental differences have vertical and horizontal designs. In the first case, the tank has a modest size, which allows it to be placed in a cramped space. Although the optimization of dimensions is more likely not even related to the cameras themselves, but to external equipment with a housing and branch communications. For example, the nipple is located in the lower part, which facilitates the process of etching excess air. Vertical accumulators for heating systems are more often used as an addition to circuits connected to submersible pumps.
In horizontal constructions, a system for separate removal of excess air is provided, which is provided by an outlet nipple with a drain pipe and a ball valve. With a lateral air vent, it is necessary to mount an additional section of the pipeline, which conceals the space, but the basis of the design is not much larger than the vertical tanks in size. In addition, the possibility of installing a hydraulic accumulator under the pump in some cases is more profitable, if not the only possible one.
Operating principle
The work cycle begins with the injection of circulating water for heating from a water source. Through the pipeline, the liquid is first directed to the membrane, and then into the expansion tank. In the process of filling the chamber, the pressure indicators change and when the set mark is reached, the circulation pump is turned off. Further, depending on the settings of the intake and consumption points, the flow of water accumulated in the tank may begin. On this cycle, the principle of the accumulator in the heating system with a different repetition rate is built. The volume of the tank directly affects the wear resistance of the system and its loading, so the technical characteristics are of paramount importance in choosing the model of the expansion tank.
The intensity of the cycles and the sensitivity of the membrane will depend on the air in one of the chambers of the tank. In ordinary models, ordinary air is used, but there are gas-air units that operate on the energy of compressed gas (for example, nitrogen). Water and gas are also separated by a membrane in order to prevent pipe airing. But, in addition to the chamber separator, a floating piston with a float mechanism that fixes the level of filling the tank with water can be used.
Expansion tank operating pressure
Experts recommend maintaining a pressure level of 0.1-0.5 bar less than the pressure gauge of the pump. For example, if the pump shows an initial value of 1.6 bar when starting the automation, then 1.1-1.5 bar will be optimal for the accumulator. As for the maximum level, depending on the model, it can be 6-10 bar. To control the pressure in the accumulator of the heating system, a relay is used that works with the same average values of 1-1.5 bar. But the most important thing is to ensure the accuracy of the testimony, excluding the influence of indirect factors during the operation of the water supply line. So, for reliability and improving tightness, it is recommended to use a fum tape with sealants at the junction of the expansion tank and the insert of metering devices.
Calculation of the volume of the accumulator
The functionality of the tank, as well as the dimensions of the structure, depend on spaciousness. Massive accumulators require more space, but they also make the system more reliable and stable. Although the accumulation of water is the main task of this equipment, it is not the only one and the calculation should be made from the understanding that the system should compensate for the pressure with a logical reduction in the number of pump starts. A typical calculation of the accumulator for heating systems according to the volume parameter is performed according to the number of sampling points:
- Up to 2 consumers - up to 50 liters.
- Up to 4 points - 80-100 liters.
- More than 5 points of water intake - 150-200 liters.
Another approach involves taking into account the power indicator. So, for 500 W the optimal volume will be 25 l, for 1000 W - 50 l, and 1500 W will correspond to 100 l or more.
Unit Installation
For the accumulator, it is advisable to provide a separate place in the boiler room, which will be protected from external influences - including temperature. For models weighing more than 30 kg, a special platform such as a screed should be prepared. It must be smooth and stable. Fastening is carried out through the legs of the structure - special hardware is screwed into the prepared platform, sometimes allowing the possibility of height adjustment. Also, the installation of a hydraulic accumulator in the heating system is performed while maintaining the possibility of future strapping and free access to adjusting mechanisms. As a rule, they leave a radius of 0.5 m of free space around, which will allow you to connect the necessary communications and carry out repair and maintenance procedures.
Accumulator connection
The expansion tank strapping scheme includes a pressure meter, a dry-running relay for the pump, purification filters and nozzles for input and output. The main water supply channel through a pressure sensor is adjusted to the minimum and maximum value. The expansion tank must immediately be guided by values 0.2-0.3 bar less than the minimum pressure level of the relay. Then, the accumulator is connected to the heating system using a five-output fitting. It is introduced into the infrastructure through a flange with an exhaust valve. You can also use a rigid hose as a transition link, which will be connected in a circuit to the pressure switch, pressure gauge and pump. Last of all, a water pipe is connected to the outlet pipe. The assembled network is tested for leaks by pressure testing, after which the pump is started.
Equipment maintenance
The tank should be regularly checked for leaks, also identifying irregularities in connections with other functional units and assemblies. Manufacturers of accumulators for heating systems recommend checking the system for air pressure approximately twice a year. To do this, a complete drain of water is carried out, after which the air pressure gauge is connected and the air pressure is already measured in the empty tank. The obtained indicator complies with the normative, after which, if necessary, pumping is performed through the air valve with a car gauge.
Conclusion
The presence of the expansion tank in the network must be pre-calculated and evaluated in terms of financial and functional feasibility. Not in every case the accumulator for heating systems justifies itself. For example, if the same risks of water hammer with stable pressure are small, then the equipment will become no more than a burden, requiring extra cash and time costs for maintenance. But private houses with a large number of coolant consumption points and complex wiring of heating circuits, even with a reliable water supply system, are recommended to be equipped with hydraulic accumulators, if only because of maintaining stable pressure indicators inside the home network.