The principle of functioning of a traditional heating system in a small house is based on circulation through the coolant pipe. For buildings whose area may exceed 100 square meters, a similar method of heating will be ineffective. This is because natural circulation contributes to the creation of pressure in the pipeline, which does not exceed 0.6 MPa. This is too small for houses that have two or three floors.
Pump need
You can increase the strength and speed of circulation in the system in one of two ways. The first involves laying a pipeline of impressive diameter, while the second involves the use of special equipment. These are circulation pumps for the heating system of a private house. The first option is quite expensive, since the cost of the pipe is high.
Pump selection by type of construction
Before choosing a circulation pump for the heating system, it is necessary to familiarize yourself with the design features of these devices. On the market you can find two types of pumps, which are conventionally called dry or wet.
Dry type equipment specifications
This type of equipment does not imply direct contact with the coolant of the working part of the rotor, since the named element is protected by o-rings. Coal agglomerate, ceramics, stainless steel or alumina can be used to produce the constituents described. This will depend on the type of coolant used. Circulation pumps for home heating systems are started and initiate the movement of the rings towards each other. Parts have a polished surface in which they touch and create a layer of water film. A similar connection is created due to the difference in pressure levels. Springs press the rings against each other, which contributes to the fact that the elements are adjusted to each other as they wear out without outside interference. Before choosing a circulation pump for the heating system, it is necessary to find out that the duration of the use of the rings is about 3 years, which is longer in comparison with the stuffing box. The latter involves periodic cooling and the presence of lubricant.
Operability
If we talk about the efficiency of pumps of this type, then it can be 80%. If you are not ready for a sufficiently high noise level, then you should not purchase such a device, otherwise it will require a separate room to install it. The circulation pump for the heating system, reviews of which are consonant with the characteristics, for this reason is not chosen so often.
Features of the wet pump
If you have wet equipment in front of you, then the impeller acts as a working moving part, which is immersed in the coolant. The latter serves as an engine cooler and lubricant. The electric component of the motor is protected from water by a glass made of stainless steel. It is installed between the stator and the rotor. The role of the material for the manufacture of the rotor is ceramic. Whereas bearings are based on graphite. The equipment case can be made of bronze, brass or cast iron. Before choosing a circulation pump for a heating system, you need to find out that wet-type units have a fairly low noise level. Such equipment has a long service life, during which no maintenance is required. If such a need arises, then the repair will be carried out quite simply, this also applies to the settings that any master can make. If you are thinking about how to choose a circulation pump for a heating system, it is important to pay special attention to the efficiency. In the wet variety of such equipment, the operability is lower by 30%.
Should I choose a wet pump?
A wet circulation pump for heating systems, the characteristics of which are presented in the article, is distinguished by the convenience of modular assembly. This indicates that at any time the owners will have the opportunity to replace the failed spare part with a new one. From a single coil unit, the accumulated air can be simply removed. If you pursue the goal of uninterrupted and continuous operation of the equipment, you need to mount the shaft strictly horizontally, which will provide access to the coolant to the bearings. Water in this case acts as a lubricant.
The main criteria for the selection of pumping equipment
If you decide to choose a circulation pump for heating systems, the characteristics of which are presented above, you must first pay attention to the level of performance. The calculation method is quite simple. The power of boiler equipment should be equated to the volume of flowing coolant per minute. Thus, if the power of the installation is 35 kW, then 35 liters of water will pass through it. At the next stage, the water flow in a separate section of the circulation is determined. To do this, use the information about the power of the radiators, which is known, and then equate the data. Choosing the pump power, it can be assumed that a pressure of 0.6 cm must be created on a 10-meter-long section. A circulation pump for a heating system can be selected according to this principle. This indicates that the normal functioning of the 100-meter pipe will be ensured with a pressure of 6 meters. It remains only to choose pumping equipment, the technical capabilities of which will provide the specified conditions.
Choosing a pump location
After reading information on how to choose a circulation pump for heating systems, you can purchase equipment and proceed to the practical part. The pump can be installed on the supply pipe after the boiler equipment and the safety group. An alternative solution is the installation in front of the boiler on the return line. Some of the masters are advised to install equipment according to the first principle, while another part - according to the second. In practice, the location does not matter and does not affect the functioning and capacity of the system. The assertion that due to the low return temperature the device will last for a longer time is also considered erroneous. Quite often, the device is installed on the return line, which is explained by the fact that when a malfunction is detected and the boiler equipment overheats, the coolant in the tank boils. In this case, the steam-water mixture will be pumped into the system. If steam enters the pump, the pumping process will be stopped, and the coolant will stop moving in the network. The boiler may explode if such a circumstance occurs.
Features of installation work
If you are thinking about how to choose a circulation pump for heating systems, then you can read the information presented above. Whereas if you are at the installation stage, it is important to follow a number of rules, among which should be highlighted the moment that the equipment can operate both in horizontal and vertical position. At installation it is necessary to observe the flow direction of the heat carrier which is specified on the case. When installing the equipment, the master must take into account the orientation of the pump in space. It must be installed so that its rotor is horizontal.
You must consider during installation so that the pump can be removed for repair and maintenance after installation. The calculation of the circulation pump for the heating system is presented above, while installation work is an easier task. The unit must be mounted on the bypass line, but the crane is installed directly. When it is turned off, the system will continue to function without forced circulation. If the installation is carried out in an open system, then the mesh filter, which is also called a mud collector, is preferable to install on the bypass, but this must be done after the screen. If it is a pressure network, the sump is located in front of the bypass. When tying a solid fuel boiler, it must be mounted in front of a three-way valve.
Wizard Tips
When the selection of the circulation pump for the heating system has been completed, installation work can begin. The unit must not be installed so that the horizontal terminal box is facing down. If there are no other options, then you should unscrew the four screws to fix the case, and then turn the equipment 180 degrees with the box. After that, the screws are replaced.
Additional nuances of installation
Calculation of the circulation pump for the heating system can be done according to the above recommendations. During installation work, it is important to observe one more subtle point. It lies in the question of the type of circuit. If in it the forced circulation of water was originally conceived, then it makes no sense to install a bypass. This is due to the fact that the coolant without the pump will still not leak, since there is no corresponding slope. In this case, the unit can be installed in the return pipe between the boiler and the expansion tank. The circulation pump for heating systems, the installation of which should be carried out according to the presented technology, should assume the presence of a bypass line only if the system involves gravity. In some cases, instead of a ball valve in a straight line, a check valve of the petal variety is installed. During pump operation, the lobe will support pressure, and the straight line will be closed. After a power outage, the pump will be stopped, the pressure will drop, while the valve will be open. This will automatically transfer the system to free circulation.