Selection of the circulation pump: the main types, the rules of choice

Self-flowing heating systems fully function only in single-storey private houses with an area of ​​up to 100 square meters. If it is necessary to heat an apartment building or a spacious mansion, then it is impossible to do without a system with forced circulation. The best solution is to select a circulation pump and install the unit in the heating circuit.

We offer to understand what tasks the pump performs in the heating system, how the device works and works. We described the features of operation of different types of pumps and outlined the main criteria for a competent choice. This information will help you choose the right model of the circulation pump and not be disappointed in the purchase.

The content of the article:

  • Why do you need a pump in the heating system?
  • The design and principle of operation of the pump
  • Types and benefits of circulation pumps
  • How to choose pumping equipment?
  • Conclusions and useful video on the topic

Why do you need a pump in the heating system?

Circulation pumps - hydraulic equipment that provides forced movement of the heated coolant in a closed loop. Such devices contribute to the uniform and rapid heating of the entire system.

Circulating pumps install:

  • in order to improve the energy efficiency of boiler equipment;
  • in cases where it is not possible to ensure the natural circulation of the liquid substance;
  • in the absence of a built-in pump unit in the heat generator;
  • for heating systems with two-pipe scheme, allowing to adjust the parameters of each individual radiator;
  • to overcome the inertia of autonomous systems with the natural circulation of fluid used for the transfer of thermal energy.

The coolant must move along the closed loop of the pipeline of the heating system at a certain speed in order to ensure the transfer of heat to the radiators.

With natural circulation This condition is not always feasible - as a result, the heating equipment does not heat up or heats unevenly.

Pump in the heating system

Installation of a pumping device for forced circulation significantly increases the efficiency of hot water systems and autonomous heating

Therefore, in heating systems install circulating pumps. Such devices provide transportation of coolant through the network at high speed, minimizing the load on the boiler. When returning to the heating element, the water remains warm, which means less energy is required for heating.

The design and principle of operation of the pump

By design, the circulation pump resembles a drainage installation. The pump consists of a robust housing made of stainless steel / cast iron / aluminum and an electrical part that includes a stator winding with an integrated ceramic / steel rotor.

The impeller is fixed on the shaft of the rotating part of the electric motor.

The impeller consists of two parallel disks connected by radially curved blades. On one of them there is a hole for the flow of heat-transfer fluid, on the other there is a small hole for fixing the impeller on the shaft of the electric motor.

The structure of the circulation pump

Body parts of circulation pumps are made of steel and durable alloys. Under the hull walls hidden rotor with fixed impeller

The motor itself is equipped with a special control board and terminals for connecting wires. In circulating pumps without electronics, a capacitor is installed instead of a board, and a speed switch is located on the terminal box.

When power is applied, the wheel with blades rotates, creating a vacuum in the nozzle and forcing the coolant. The rotor creates movement of the working fluid in the direction from the inlet to the exhaust valve.

The pump constantly takes water from one side and pushes it into the heating system on the other. Centrifugal force facilitates the transport of fluid throughout the line.

The created pressure overcomes the resistance in different parts of the circuit and ensures the circulation of the coolant.

Types and benefits of circulation pumps

By design features, pumps for forced circulation are divided into pumping units with a wet rotor and high-performance devices with a dry rotor.

Wet Pumps. The rotor and the impeller of such pumps are in direct contact with the working fluid, which simultaneously performs two important functions: the role of lubrication and cooling of the instrument. The rotor and stator in such pumps are separated by a special vessel, which is responsible for the tightness of the elements of an electric motor under voltage.

Wet-type circulation pumps are equipped with a stepped speed controller. This allows you to choose the optimal mode of operation, and thus control the power consumption.

Internal device of the pump

The rotor of the electric motor and the impeller in the pumps are in the pumped water, which humidifies the supporting elements and constantly cools the engine (+)

Units with a wet rotor have a modular design. Separate modules are selected depending on the required head and performance. The prefabricated design greatly simplifies pump repair, since a failed module can be quickly and easily replaced with a new one.

Circulating pumps of this type involve small heating systems. They function almost silently, and therefore are great for installation in residential areas.

The motor of wet-rotor pumps does not need additional cooling, as it constantly contacts with water. Inside the pump there is a small amount of working parts, which minimizes the need for frequent maintenance.

The main advantages of using a “wet” type pump:

  • low noise level;
  • small overall dimensions and small weight;
  • minimum electricity consumption;
  • easy parameter setting, maintenance and repair;
  • long service life.

There are drawbacks with wet rotor units. They are very sensitive to the quality of the working fluid. The presence of fine abrasive particles in water leads to accelerated wear of the hydraulic part of the pump.

In addition, the efficiency of such circulation pumps does not exceed 55%. However, this indicator is quite sufficient for pipelines of small length, and therefore pumps that are in direct contact with water are often used in individual heating systems.

For trouble-free functioning of wet-type units, it is necessary that pump installation was executed correctly. The main requirement is a strictly horizontal spatial orientation of the shaft. Only with this configuration provides a full lubrication of bearings with fluid.

Competent installation of the circulation pump

Competent installation of a circulating pump is the key to stable operation of the heating system throughout its life.

Dry rotor pumps successfully used for pumping large volumes of coolant in large installations. The rotor assembly of such devices is not in contact with water.

The casing part of dry-type circulation pumps is made from durable cast iron or galvanized steel. The surface is covered with special protective compounds to prevent corrosion.

Units with a dry rotor are suitable for collective use in residential high-rise buildings, entertainment centers and offices, at industrial facilities.

Dry rotor pump

The design of the pumps "dry" type provides increased power. Such pump models are capable of creating a lot of pressure in the heating circuits (+)

There is a special sliding seal (2 protective rings) between the electric motor and the pump part of the pump, which isolates the basic functional elements from liquid ingress.

These rings are well polished and are in close contact with each other. One of them (dynamic) mounted on a rotating shaft. The static wheel is firmly fixed in the pump housing.

A thin water film reliably seals the connection of the protective rings due to differences in pressure in the circuit and the external environment.

For the manufacture of sealing rings using coal obtained by the method of oil agglomeration. In some versions of pumps designed for use in extreme conditions, metal / ceramic protective rings are installed.

The efficiency of devices with a dry rotor reaches 85%. This is an excellent indicator in comparison with pumps "wet" type. However, "dry" units produce a lot of noise due to the cooling fan, and therefore they are mounted in separate rooms with good sound insulation.

Dry type circulation pumps come in 3 types:

  • monoblock;
  • cantilever;
  • "In-line".

Monoblock pumps belong to the category of low-pressure units. The electric motor and the pump in such devices are mounted in one block. They are easy to operate and maintain. Suitable for use in public utilities and apartment buildings.

Console pumping devices are collected on a single basis, with the axes of the pump and the engine being in line. The suction nozzle is located on the outer part of the cochlea, the discharge is in the opposite side of the body.

In-line pump

If console units are installed at manufacturing plants, as well as in urban water supply systems, then In-line pumps are installed directly on the pipeline

In-line pumps mounted directly on the pipeline pipeline. Suction inlet and pressure outlet nozzles are located on the same line, an automatic mechanism for compensating the production of sealing rings is provided.

Benefits of using a dry rotor circulating pump:

  • high performance;
  • energy efficiency;
  • Low requirements to the quality of the energy carrier - the pumped liquid may contain neutral impurities;
  • simple repair and replacement of spare parts.

In addition, today, manufacturers of heating equipment offer potential dual models of pumps to potential buyers. Such devices are used for power redundancy and additional safety net in emergency situations.

Dual pump motors can function together or separately. If one pump fails, the second device continues to operate normally, ensuring uninterrupted boiler operation.

Dual circulation pumps

Reliable and trouble-free operation of the heating system will provide dual circulation pumps, in which two impellers are connected in parallel

With proper operation, the service life of the circulation pump is at least 10 years.

How to choose pumping equipment?

The efficiency of the pump depends on the basic parameters - performance and pressure. Capacity shows the amount of coolant fluid that the unit must pump over a unit of time. This parameter is determined from the conditions of maximum load.

Head is a quantity that expresses the energy of the flow of a fluid used as a carrier of heat. Considers the hydraulic resistance of the entire system.

You should also pay attention to the maximum temperature. Since the pump will pump the heated water, it must withstand up to 110 ° C.

It is very important to choose a suitable power circulating pump. Low-power device can not cope with the transfer of fluid coolant in the desired volume. Pump parameters are selected based on calculations.

If you install a more powerful unit, an unpleasant noise will appear in the pipeline. Also in this case, the functional elements of the boiler equipment will wear out much faster than stated by the manufacturer.

Proper installation of the circulation pump

The power of the circulating pump must be sufficient to cope with the hydraulic resistance in a closed loop

Experts recommend choosing a circulating pump at the design stage of the heating system. If the length of the pipeline does not exceed 80 m, it is enough to install one pump. With a greater length, it is advisable to install several pumping devices at once.

When buying, you should pay attention to the materials from which the functional elements of the pump are made. Most of the parts are directly / indirectly in contact with the heated working fluid, and therefore subject to rapid wear.

Therefore, it is advisable to give preference to circulation pumps with ceramic bearings and a rotor assembly.

An important role is played by electronics. To regulate the temperature indicators inside the premises in the heating circuits establish thermostatic valves. When the temperature rises, they overlap, the pressure in the pipes increases.

As a result of these processes, an unpleasant noise appears. To get rid of it, it is necessary to transfer the circulation pump to a lower speed, and it is inconvenient to do this manually.

Quickly and effectively cope with this task will help pump with integrated electronics. Such units smoothly regulate pressure drops in the pipeline depending on changes in the amount of fluid.

Compact overall dimensions of the pump

The main advantages of modern pumps are cost effectiveness and durability, compact overall dimensions, low noise level, automatic operation mode, convenient control panel

It is worth noting the additional functionality of the pumps, namely:

  • smooth adjustment;
  • speed control;
  • automatic mode;
  • built-in informative display.

The simplest circulation pump models - without the ability to adjust the speed of transportation of fluid. Modern multifunctional pumps are two / three-speed units with a smooth adjustment. They are highly accurate settings.

Equipment operating in automatic mode is equipped with a control panel. The settings of such devices are extensive and depend only on the modification of devices.

This may be an automatic speed adjustment depending on changes in temperature indicators of air. indoors, electronic off / on timer, automatic pump start at minimum speed flow.

The presence of a digital display makes it possible to obtain all the necessary information about the operation of the pump. devices: temperature of the heat-transfer fluid, resistance in a closed loop, capacity, errors, etc.

Conclusions and useful video on the topic

Rules for the selection of circulating equipment in the video:

The subtleties of calculating the pressure and performance in the video clip:

Video about the device, the principle of operation and installation of the circulation pump:

Modern heating system with built-in pump for forced circulation allows to heat the living premises in a matter of minutes after the start of the heat generator.

Rational selection of a circulating pump and high-quality installation significantly increase the efficiency of use of boiler equipment by saving energy resources by about 30-35%.

Looking for a circulation pump for the heating system? Or have experience in operating such facilities? Please share your experience with readers, ask questions and participate in discussions. The comment form is located below.

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