Circulation pump for heating: device and principle of operation, how to choose a pump for a private house

One of the main elements of hot water supply and heating system is the heating pump. A circulation pump is a device that is installed in the heating system pipeline and is designed to ensure the forced movement of water through it. Thanks to such a device, all rooms of the structure are heated evenly and quickly.

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Device and principle of operation

The circulating pump for heating is highly specialized device. Its body is made of stainless alloyssuch as bronze, steel, aluminum, cast iron or brass. A rotor is made of steel or ceramic and is driven by an electric motor. For efficient fluid circulation, the rotor shaft equipped special wheel with blades (impeller).

The main structural elements of the circulation pump:

• pump housing;
• impeller;
• rotor;
• motor shaft;
• terminal box;
• engine;
• air propeller.

The rotor begins to rotate as soon as electrical power is applied to the stator winding of the device. The rotation of the rotor is transferred to the impeller, in the working chamber of which

vacuum is created in the supply line. This facilitates the suction through it of water from the pipeline.

The centrifugal force acts on the liquid, which leads to an increase in the pressure in the coolant chamber and its expulsion through the discharge pipe into the heating system. Under the pressure of the flow created by the pump, the heat carrier circulates through the heating system freely, while overcoming the friction force.

The important indicators of the unit are performance and power. They are closely interconnected and affect the rate of fluid circulation in the system.

Varieties of pump devices

All pumps for the heating network are divided into 2 types. Each of them performs the same tasks, but differs in technical parameters:

1. Dry rotor. In this case, the rotor has no contact with the coolant - the liquid working medium. The impeller is separated from the stator and rotor by steel rings that act as seals. Their tightness is ensured by a layer of water formed due to the pressure difference in the external environment and the heating system.
2. Wet rotor. In such devices, the rotor and impeller are in contact with the coolant. This working medium cools the fluid and acts as a lubricant. The rotor and stator are isolated from each other by a special glass made of stainless steel. It protects the stator winding from water ingress on it, as it is energized.

Dry rotor pumps are characterized by good performance and high efficiency. But they create noise during operation. There are difficulties in maintenance, operation and repair. They are used in household heating systems. rarely.

The efficiency of pumps with a wet rotor is low, but sufficient to ensure the circulation of the coolant in small rooms. It has high reliability, operates with minimal noise, is easy to operate, repair and maintain.

Pump Specifications

It is worth paying attention to the technical characteristics of some pump positions. The main indicators that are indicated in the pump passport are pressure, flow and power.

Water pressure

Pressure (head) is measured in atmospheres or "water columns meter". The regulatory documentation contains tables with translation from one system to another.

The pressure must be calculated for each room and building. It should be optimal, without hydraulic losses in pipes and connections. In the technical passport, a graph is attached to the device to determine the power and pressure.

It is necessary to select the pump speed and calculate the head as the sum of the hydraulic resistances of the entire system. It is calculated without taking into account the height of the building. For ten meters of the length of the circulation ring, 6 atmospheres is considered optimal.

Consumption

The flow rate is understood as the amount of heating load. It is calculated by specialists when drawing up a heating system for the entire building or room.

For self-calculation, you can use thermal standards. For example, 1 kW of heater power is taken to heat a room of any height with an area of ​​10 m². One section of the radiator has 200 watts. Therefore, to heat a room with such an area, 5 sections will be needed.

Pump power

This value is determined by the formulas, but they do not take into account external factors for the heating process and performance. And you need to consider:

• ambient temperature;
• pipe diameter;
• coolant viscosity;
• operating time of the device;
• the presence of a double heating circuit.

Selecting a circulation pump must be powerful, with good performance and high pressure.

Equipment installation rules

It is better to entrust the installation of the circulation pump to specialists. But if you do it yourself, then you need to know the basic rules for installing the device:

1. The equipment must be installed in a horizontal position near the boiler on a return line. There, the temperature data of the coolant is the lowest.
2. The pump must be installed so that the arrow on the body coincides with the movement of the coolant. Two shut-off valves, a non-return valve and a cleaning filter at the inlet carry out the pump piping. Threaded connections are treated with sealants.
3. A bypass is formed additionally if the device is installed in a heating system with combined circulation. A bypass is a pipe section on which shut-off valves are installed. It is installed parallel to the pump and, if necessary, allows you to switch the heating system to natural circulation.
4. After installing the pump, it must be filled with a coolant, and excess air removed.

If the pump is installed correctly, then the liquid enters the system evenly, and there are no air locks in the boiler. It is necessary to provide free access to the equipment for maintenance and possible repairs.

Criterias of choice

A correctly selected circulation pump guarantees a comfortable temperature. To do this, it is necessary to select the correct device according to the parameters of the heating system. It's important to know:

• network;
• coolant;
• pressure in the system;
• features of heating devices;
• temperature regime;
• pressure drop between supply and return;
• area for heating.

The knowledge of the network (single or double-circuit) will determine the number of pumps that need to be installed for the comfortable operation of the system.

The most common are heat transfer fluids. It can be water or special antifreeze.

Circulation pressure rises in the system under the pressure. It can be natural and is formed due to the difference in the density of water, or it can be created artificially using a pump. The efficiency of the heating system depends on the knowledge of this calculated parameter.

It is not easy to choose the ideal version of heating boilers due to their large assortment, therefore, knowledge of the technical parameters of heating devices is necessary for the correct installation of the entire system.

The temperature regime, which everyone is obliged to observe, is established on the basis of sanitary standards.

For the functioning of any heating scheme, it is necessary to know the optimal fluid pressure in the system, its differences are regulated by building codes (SNiP) and special rules.

Knowing the area of ​​the room, you can calculate by calculation how much heat is required to heat it.

After receiving these data, based on the analysis and calculations of indicators and the study of the regulatory documentation, you can tell exactly how to choose a pump for heating and what performance it is should have.

Specialist recommendations

Choosing a pump for the heating network according to the characteristics of the device, you need to focus on the recommendations of experienced specialists:

1. The choice must be given to the model, the technical indicators of which correspond to the calculated values ​​when designing the heating system.
2. It is not advisable to choose a pump with a large capacity margin. Such a device, using its power not in full, will consume more electrical energy and create noise during operation.
3. It is better to choose those models for which you can adjust the operating modes. Such devices optimize the operation of the entire heating system as a whole.

Today, a number of European countries are engaged in the production of such pumps. The products are characterized by good quality, convenient installation and maintenance, as well as a long service life.

To answer the question of how to choose a circulation pump for heating private houses, cottages and summer cottages, the rating of manufacturers of pumping equipment, compiled according to customer reviews, will help.

The German concern Wilo S. E., which is well known to the Russian consumer for the production of pumping equipment. For example, the Wilo - Stratos model is characterized by the following technical indicators:

• head 4.9 m;
• consumption - 2.5 m³ / hour;
• power - 59 W.

Manual and automatic modes of operation are inherent in this model. They can adjust the rotor speed and pressure drops. They are equipped with a release function.

The Italian company DAB specializes in the production of circulation pumps, which can be given second place. It produces devices for both industrial facilities and private use. For example, the EVOTRON 40/130 model is equipped with a convenient digital display that allows you to control the pump operation modes.

The third place is taken by the manufacturer of pumping equipment - the Danish company Grundfos. The range of the company is very extensive. The main feature of these pumps is a wide range of temperature indicators; they function well at temperatures from -25 to -110 degrees.