Circulation pump driven by an electric motor with a wet rotor. Circulation pump. With wet or dry rotor? Types of circulation pumps

Glanded rotor pumps are used to supply liquids with high pressure. They are best suited for supplying coolant and aggressive media. Unlike glandless pumps, in these pumps the liquid does not come into contact with the motor.

Another difference from glandless pumps is the way the pump body/shaft is insulated. This is achieved using stuffing box or sliding mechanical seals (STU).

Standard glanded rotor pumps typically use three-phase constant speed motors. Typically, they are controlled via an external electronic speed control system. Today, dry rotor pumps are available with a built-in electronic speed control unit, which, thanks to modern technology, can also be installed on motors with high power output.

The overall efficiency of dry rotor pumps is significantly higher than that of wet rotor pumps. Glanded rotor pumps are divided into three main types:

In-line pumps
Pumps in which the suction and discharge pipes are on the same axis and have the same nominal diameter are called in-line pumps. In-line pumps are equipped with standard air-cooled flange electric motors. This type of pump is considered most suitable for building systems that require high power output. These pumps are installed directly on the pipeline. In this case, the pipeline is secured with brackets or the pump is installed on a foundation or a separate bracket.

Block pumps
Block pumps are low-pressure, constant-speed centrifugal pumps with a standard air-cooled electric motor. The liquid enters the pump in the axial direction and exits in the radial direction. Brackets or supports for the motor are included as standard with the pumps.

Cantilever pumps
These centrifugal pumps have an axial inlet and a radial outlet of the liquid from the pump. The pump and motor have independent mounting units. Therefore they are installed on a foundation slab.

Depending on the fluid and operating conditions, they can be equipped with a STU or gland seal. The nominal bore of such pumps is determined by the pressure pipe. The suction pipe has a larger nominal bore.

Shaft seal
The shaft can be sealed (as standard or as an option, in the case of cantilever pumps) from the atmosphere using STU or a gland seal. Below is a description of these two types of seals.

STU pump with dry rotor

Mechanical seals
The mechanical seal design is based on two rings with highly polished surfaces. They are pressed against each other using a spring and work together. STU are dynamic seals and are used to seal a shaft rotating in a liquid at high operating pressures. The STU consists of two polished wear-resistant rings (for example, silicone or graphite), which are pressed against each other by axial forces.

One ring (dynamic) rotates with the shaft, while the other ring (static) is fixedly fixed in the housing. A thin film of water forms between the sliding surfaces, serving as a lubricant and cooling agent. Depending on the operating mode of the pump, several types of friction of the mating surfaces are possible: mixed friction, boundary friction or dry friction, and the latter (occurring in the absence of a lubricating film) causes immediate destruction of the surfaces.

The service life depends on operating conditions such as the composition and temperature of the working fluid.

Gland seals
The materials used for glands are high-quality synthetic fiber yarns such as Kevlar® or Twaron®, PTFE, porous graphite yarns, synthetic mineral fiber yarns, and natural fibers such as hemp, wadding or ramie.

Material for oil seals is produced in the form of threads or compressed skeins, dry or with special impregnation, depending on the purpose. If the material is purchased in the form of threads, you first need to form a ring and give it shape. The seal ring is then wrapped around the pump shaft and tightened using a crimp sleeve.

Installation types

Acceptable installation methods
In-line pumps are designed for horizontal and vertical installation directly on the pipeline.
To dismantle the motor and pump elements, sufficient space must be left.
When connecting pipelines, the stress and weight of the pipelines should not be transferred to the pump, and the pump should be installed on supports (if any).

Unacceptable installation methods
Installation with the motor and terminal box pointing downwards is not permitted.
If the motor power exceeds a certain level, the manufacturer should be consulted before installing the pump in a horizontal position.

- Section view of a high pressure centrifugal pump
- Characteristics of high pressure centrifugal pump

High pressure centrifugal pumps

These pumps are usually multi-stage. The flow rate of the pump depends on the size of the impeller and other factors. The pressure in high-pressure centrifugal pumps is achieved by using several impellers installed in series. Kinetic energy is converted into pressure partly in the working and partly in the straightening apparatus.

Thanks to the ability to vary the number of stages, high-pressure centrifugal pumps develop higher pressures compared to low-pressure single-stage centrifugal pumps.

Some pumps have up to 20 stages. Thus, they can provide a head of up to 250 m. Almost all of the high pressure centrifugal pumps that we have described belong to the dry rotor pump family. However, recently manufacturers have been successfully equipping them with wet rotor motors.

Special instructions for block pumps
Block pumps must be installed on suitable foundations or brackets.
Installation of a block pump with the motor and terminal box pointing downwards is not permitted. All other installation methods are considered acceptable.
For detailed information on installation methods, see the installation and operating instructions.

Such products are widely used both on an industrial scale and in everyday life. They are compact devices that perform the function of pumping liquids through pipelines. Mainly installed in hot water supply, heating and cold water supply systems.

Due to the design and application features, even with a long route, to ensure reliable operation of the circuit, it is enough to install a circulation pump of relatively low power.

They are used not only to ensure the movement of water. They are capable of pumping liquid media whose temperature ranges from -40 to +130 0C. Asynchronous motors are used as the power element. Circulation pumps are classified in different ways. Depending on the design, they are divided into 2 types: models with a “dry” and “wet” rotor. This difference in engineering solution largely determines their functional purpose.

What are circulation pumps with a dry rotor made of and what are they?

The design of the circulation pump with a “dry” rotor provides increased power, which significantly increases its productivity. Such models are capable of creating high pressure in systems and are used for long-distance pipelines, or if it is necessary to supply fluid to a great height. That is why they found their main use for industrial purposes.

They consist of two main parts - an electric motor and the pump itself - which have a coupling connection. They got their name because the rotor does not have direct contact with the liquid. In turn, they are all divided into subspecies.

KM (console K) are an assembly mounted on a common platform. The axes of the pump and motor are located strictly on the same line. They are most widely used in urban water supply systems and in enterprises to meet production needs. Can work with both clean and contaminated liquids.

Cantilever-monoblock KMLs are considered low-pressure. The pump and motor are mounted in a common housing. They are easier to operate and maintain, therefore they are more widely used in public utilities and are installed in general building utilities. The design of a circulation pump for heating is simple and is no different from the design of models used in other systems.

What these subspecies have in common is that the inlet and outlet pipes are located at an angle.

“In-line” pumps are distinguished by the fact that they can be installed directly on the pipe line. Their pipes are located on the same axis. By design they are more reliable. The natural wear and tear of the connecting rings (between the pump and the motor) during operation is automatically compensated by a pressure spring. “Self-fitting” of parts occurs.

Design features of pumps with a “wet” rotor

Models with a “wet” rotor are characterized by a low level of noise generated. They are of interest from the point of view of domestic use. They are widely used in the installation of autonomous heating systems in private buildings or in small administrative and industrial premises. The pump rotor is located directly in the liquid.

They are attractive because they are easy to repair at home. But in order to eliminate the malfunction, you need to know the design features. Therefore, let’s take a closer look at how a circulation pump with a “wet” rotor works.

For the manufacture of the body of models for heating, cast iron is usually used, although products are produced in which the body is made of stainless steel (non-ferrous metals, aluminum, bronze, brass). They are used for hot water supply and cold water supply systems. The rotor is placed in a special glass and is rigidly connected to the impeller (impeller).

This achieves its isolation from the stator. The peculiarity of the technology is that the shaft can be either metal or ceramic. It is secured in plain bearings (graphite or ceramic). The volute, on which the inlet and outlet pipes are located, is attached to the body using bolts, which are unscrewed with a special key (hexagon) supplied with the product.

There is a plug on the front (end) part of the pump; by unscrewing it, excess air can be released. Although it is also possible to automatically remove it during operation. For this purpose, an air vent is located in the upper part. There is a box for electrical connection with an operating mode regulator.

When the plug is completely unscrewed, access to the shaft opens, on the end of which there is a slot for a screwdriver. Thus, you can manually scroll if the pump does not start after a long “idle period” (for example, due to salt deposits). Perhaps the only drawback of such pumps is their low efficiency. If for “dry” models it is within 70–80%, then for “wet” models it does not exceed 55%.

But at the same time, such a circulation pump design has a number of undeniable advantages:

the liquid it pumps simultaneously cools and lubricates the parts;
upon startup, the products automatically remove trapped air;
The pumps are assembled according to a modular principle. Therefore, when repairing, it is enough to replace the faulty part;
due to low power, they consume little electricity;
switching of operating modes is provided, which allows you to choose the most optimal one;
the ability to automatically regulate the start and stop process when using a temperature sensor, which also reduces energy consumption;
absolute silence in operation;
does not require maintenance.

The latest models of “wet” pumps are produced shaftless. The impeller (also known as the rotor) rotates on ceramic bearings under the influence of the electromagnetic field created by the stator winding. This significantly simplified the design (no shaft and oil seals) and increased reliability and durability. Even if small fractions get inside along with the liquid, it will not affect the operation of the pump.

Glandless rotor pumps, which can be purchased in Moscow at a budget price in the EGM-SHOP.ru online store, are designed to complete autonomous heating, hot water supply and air conditioning systems low-rise residential buildings and cottages.

Their main purpose is to maintain uninterrupted coolant circulation for the most efficient distribution of thermal energy and timely supply of hot water to water consumption points.

Design of DAB glandless pumps

The name of circulation pumps with a wet rotor reflects their key design feature - rotation rotor in the pumped coolant, thereby ensuring cooling electric drive and lubricants bearings.

For protection stator a special system is provided to prevent coolant from entering separating glass carbon fiber or stainless steel.

Advantages of DAB circulation pumps with a wet rotor

A wide range of models and designs, from simple inexpensive to energy-efficient frequency-controlled;
Three speed modes allowing you to adjust the heating speed of any room;
Low noise level during operation;
Light weight and compact dimensions;
Long period of non-stop work;
Quick and easy installation and configuration;
Minimal maintenance;
High maintainability.

In addition, pumps for circulating water and increasing pressure in the heating system, equipped with a wet rotor, reduce costs for space heating and hot water supply. They consume less energy and are designed to complete pipelines with a smaller cross-section, which allows rational consumption of heat due to the rapid and intensive movement of the coolant.

Today you rarely see a home heating system built according to the classical gravitational scheme. Almost everywhere a circulation pump is used for heating. This device is useful and functional, but reduces the overall precision requirements for piping network design. At the same time, without a forced circulation source, it is impossible to operate such high-tech heating systems in a private house or apartment, such as heated floors.

Circulation pump design - implementation of a standard scheme centrifugal machine. The main structural components include:

pump housing;
a rotor that transmits rotation from the engine shaft to the turbine block;
turbine impeller with inclined blades, which is also called an impeller;
means of sealing, insulation from water or coolant;
the main electrical circuit that switches operating modes and monitors engine parameters.

Circulation pumps can have different body shapes and locations of outlet and inlet pipes. This is done so that the device can be easily installed and maintained under the operating conditions for which it was designed. In particular, the selection of a pump can be made according to the type of connection: with a flange, a threaded connection, or a nut.

The circulation pump has small dimensions. It is often built directly into the internal cavity of the housing of domestic gas heating boilers. Safety devices can be installed with the pump. The small size of the blower is easy to understand if you consider the purpose of circulation pumps. They do not require record liquid supply power. In fact, they literally move water horizontally.

The task of circulation pumps is to overcome the hydraulic resistance of pipelines. If the collector group of a warm floor is considered, the blower is busy creating a flow of very small volume as such, since no significant gravitational forces exist in a heating circuit of this type.

The principle of operation of the circulation pump can be illustrated by several points.

The coolant enters the inlet pipe.
When the engine is turned on, the rotational torque is transmitted through the rotor to the turbine wheel.
Rotating, the wheel moves water with inclined blades, which moves to the edge of the disk under the influence of mechanics (distribution of forces along an inclined plane), as well as due to centrifugal force.
As you approach the edge of the disk, the speed of the water flow increases, as does its pressure.
The liquid is discharged into the outlet pipe.

As the water or coolant moves to the edge of the turbine wheel, a vacuum arises in the inlet pipe; it captures a new portion of the working fluid for transportation.

Important! The circulation pump of a gas or solid fuel boiler is capable of effectively servicing a certain length of pipelines, pumping the volume of coolant stated in the characteristics. If greater performance and pressure are required, it is not necessary to buy a separate, external supercharger. An additional pump can be installed in the system, which will create the necessary flow or help raise water to the second floor. The same is done when building a distributed, zoned floor heating system.

Both a conventional home heating system and a dual pump heating system can use different types of blowers. The main difference between the models offered on the market is the engineering solution of the rotor-turbine zone.

Glandless Rotor Pumps

Glandless circulation pumps - the most common type of supercharger for the heating system of a private house or apartment. The devices are so named due to the fact that the operation of the units occurs directly in the coolant.

The rotor is placed in a special glass with sealing or vortex protection against leaks.
During operation, rotor parts, including plain bearings, are in water or coolant.
Continuous lubrication and cooling of structural parts occurs.

Thanks to these operating features, wet systems are stable, maintenance-free, low noise.

To prevent air from entering the rotor area, the pump is equipped with exhaust outlets. The upper one is designed for operation of the automated system, and gas is released through the one located in the front part of the housing during commissioning operations or adjustments.

Important! Operating a pump with a wet rotor when air gets into the pipelines causes sharply increasing wear of moving parts, overheating, jamming or irreparable damage to equipment. The presence of abrasive particles in the coolant is not recommended. Therefore, a glandless water pump should only be installed in a closed heating system.

Dry rotor pumps

The pump with a dry rotor is designed with careful isolation of the turbine block from leaks. The system has a number of advantages and disadvantages.

The advantage of dry systems is better cooling - most components do not come into contact with hot coolant in the heating system.
Dry pumps are noisier.
The overall level of reliability of pumps with a dry rotor is lower due to the larger number of seals and lack of constant lubrication.

However, the main advantage of dry-type superchargers is that they are not afraid of airing. They are also less bothered by the abrasive suspension in the water - only the turbine suffers from it, which has a much higher failure life than the rotor unit with its plain bearings. Therefore, such blowers should be chosen if an open heating system with a circulation pump is being built.

Advice! The danger of an open heating system for a circular pump is the likelihood of airing, hydraulic surges and the formation of an abrasive suspension in the coolant. Due to contact with air, water is constantly saturated with oxygen, oxidation processes are accelerated, especially if steel pipes or heating radiators are used. The amount of rust in the coolant increases. In such conditions, the use of a pump with a dry rotor is recommended.

Variable Speed Pumps

The speed of the pump in a heating system plays a big role. By changing it you can achieve:

optimal operating mode of heating equipment;
stabilizing the temperature of all radiators, regardless of their distance from the boiler;
reducing the temperature of the coolant while maintaining constant heating efficiency, since with a higher circulation rate the water loses less energy in each pass.

Today, various technical pump solutions are available on the market. Home heating can use a single-speed model, the performance of which must be selected in accordance with the characteristics of the boiler and the total volume of coolant. Offered two, three, four-speed models. Their work is based on changing the switching circuit of the motor's pole pairs.

A more technologically advanced, but also significantly expensive solution is frequency control. This type of pump does not provide stepwise switching, but smooth speed control. This allows you to very finely tune the operation of the heating circuit.

The use of circulation pumps in home heating

Since some features of the operation of water circulation pumps in various heating schemes have already been mentioned above, we should touch upon the main features of their organization in more detail. It is worth noting that in any case, the supercharger is installed on the return pipe; if home heating involves raising the liquid to the second floor, another instance of the supercharger is installed there.

Closed system

The most important feature of a closed heating system is sealing. Here:

the coolant does not come into contact with the air in the room;
inside the sealed pipeline system the pressure is higher than atmospheric;
The expansion tank is built according to the hydraulic compensator circuit, with a membrane and an air area that creates back pressure and compensates for the expansion of the coolant when heated.

Note! For a closed circuit, you can make an expansion tank with your own hands. Its capacity is calculated using simple formulas and depends on the total volume of water in the system.

There are many advantages to a closed heating system. This includes the ability to desalt the coolant to ensure zero sediment and scale on the boiler heat exchanger, and to fill in antifreeze to prevent freezing, and the ability to use a wide range of compounds and substances to transfer heat, from an aqueous-alcohol solution to machine oil.

The diagram of a closed heating system with a single-pipe and two-pipe type pump is as follows:

When installing Mayevsky nuts on heating radiators, the circuit adjustment is improved; a separate air exhaust system and fuses in front of the circulation pump are not needed.

Important! A closed heating system, built without tilting the pipes or maintaining the level of the main coolant flow lines, does not work without a circulation pump. It also does not function when the power is turned off.

Open heating system

The external characteristics of an open system are similar to a closed one: the same pipelines, heating radiators, expansion tank. But there are fundamental differences in the mechanics of work.

The main driving force of the coolant is gravitational. The heated water rises up the accelerating pipe; to increase circulation, it is recommended to make it as long as possible.
The supply and return pipes are placed at an angle.
Expansion tank - open type. In it, the coolant comes into contact with air.
The pressure inside an open heating system is equal to atmospheric pressure.
The circulation pump installed on the return flow acts as a circulation amplifier. Its task is also to compensate for the shortcomings of the pipeline system: excessive hydraulic resistance due to excessive joints and turns, violation of inclination angles, etc.

An open heating system requires maintenance, in particular, constant topping up of coolant to compensate for evaporation from the open tank. Also, corrosion processes are constantly occurring in the network of pipelines and radiators, due to which the water is saturated with abrasive particles, and it is recommended to install circulation pump with dry rotor.

The diagram of an open heating system looks like this:

An open heating system with the correct angles of inclination and sufficient height of the expansion pipe can be operated and when there is a power outage(stopping the circulation pump). For this purpose, a bypass is made in the pipeline structure. The heating circuit looks like this:

If the power supply is interrupted, it is enough to open the tap on the bypass loop so that the system continues to operate on a gravitational circulation circuit. This unit also makes the initial heating start-up easier.

Warm floor system

In a heated floor system, correct calculation of the circulation pump and selection of a reliable model guarantee stable operation of the system. Without forced water injection, such a structure simply cannot work. Pump installation principle next:

Hot water from the boiler is supplied to the inlet pipe, which is mixed through the mixer block with the return flow of the heated floor;
The supply manifold for the heated floor is connected to the outlet pipe of the pump.

The distribution and control unit for a heated floor looks like this:

The system works according to the following principle.

At the pump inlet it is installed main thermostat, controlling the mixing unit. It can receive data from an external source, such as remote sensors in the room.
Hot water at a set temperature enters the supply manifold and is distributed through the underfloor heating network.
The return return has a lower temperature than the supply from the boiler.
The thermostat, using a mixer assembly, changes the proportions of the hot boiler flow and the cooled return flow.
Through the pump, water of the set temperature is supplied to the input distribution manifold of the heated floor.

Important! In such a structure there is no gravitational component of circulation. Therefore, when the power and pump are turned off, the heated floor simply does not work.

Main characteristics of circulation pumps

The main characteristics by which the choice of circulation pump is made:

pressure, showing the ability of the device to raise water to a certain height;
productivity and consumption, showing how much fluid the supercharger supplies per unit time.

These parameters are key in calculating the heating system. The pressure will allow you to understand whether the blower is capable of serving a pipeline network with a certain height difference. And the flow rate is calculated according to the requirements of the heating boiler for the planned volume of coolant.

Another factor that is often very important for the user is the mounting size of the device. This is the size of the pump; it is carefully considered if the supercharger is planned to be embedded into an existing pipeline, while ensuring a neat and inconspicuous installation.

Contains all the data the user needs markings on the front panel. The numbers on the circulation pump mean:

type of device (most often it is UP - circulation);
type of speed control (not specified - single-speed, S - step switching, E - smooth frequency control);
diameter of the pipes (indicated in millimeters, means the internal dimension of the pipe);
pressure in decimeters or meters (may differ among different manufacturers);
installation dimensions.

The pump marking also contains information about the types of connections of the inlet and outlet pipes. The complete coding scheme and word order looks like this:

Responsible manufacturers always follow standard labeling rules. However, individual companies may not indicate some of the data, for example, installation dimensions. You need to find it out directly from the documentation for the device.

The choice of a circulation pump is always made after a careful calculation, which takes into account the type of heating equipment, the volume of coolant, elevation differences, and the minimum required blower performance.

Advice! You cannot buy products from unknown companies that copy products from reliable and popular brands. Such a pump is an ineffective investment. The use of low-quality materials, impellers, and turbines with limited service life leads to rapid failure of the supercharger. On specialized forums you can find many scary stories in photographs about the kind of technological nihilism that the housings of Chinese “no-name” products contain.

Therefore, it is worth choosing a pump only from trusted brands. Reliable devices are also available in the mid-price category. And if you need the highest quality and have the opportunity to pay one and a half to two times more, you should pay attention to products from the GRUNDOFS and WILO brands.

Review of popular models

It is impossible to give a clear name of the model of the best among superchargers without a clear segmentation according to their operating conditions. Therefore, the rating of heating circulation pumps represents the competition between brands and the key features of the equipment they offer.

1. Grundfos UPS

One of the most popular and high quality types of pumps. A company with roots in Denmark ensured maximum reliability using stainless liners, ceramic bearings, and turbine wheels made of composite materials. Glandless rotor pumps have the following features:

low energy consumption, from 45 to 220 W;
very low noise level (up to 43 dB) and vibrations - you can understand that the pump is working only by placing your hand on it;
wide temperature range from 2 (-20 for some models) to 110 degrees Celsius;
simple installation;
unpretentiousness, lack of maintenance;
durability, service life is at least 10 years.

Grundfos UPS pumps are very compact and lightweight. Their disadvantages include high price up to 2 times higher than competitors. However, the popularity of the products of this brand suggests that their characteristics justify the price tag.

Pump Grundfos UPS 25/40

Products from this brand are considered the most reliable. Only proven and simple solutions are used in their design and electronic circuits. The pumps are characterized by:

efficiency;
simple power adjustment;
reliability, durability - cast iron housing, turbine wheel made of polypropylene, bearings made of metal graphite, stainless shafts;
operating temperature from -10 to 110 degrees Celsius;
protection against voltage surges and surges;
ease of installation.

Wilo Star-RS pumps are compact, lightweight, maintenance-free. Their price is also higher than that of competitors, but lower than that of the leader in the rating. Users note that at the highest speed the pump begins to make noise over time.

Pump Wilo STAR-RS25/4-130

The Compass series is a reasonable choice, a strong mid-ranger with attractive characteristics and cost. The pumps are distinguished by:

efficiency;
simple speed switching circuit;
small dimensions;
fairly low noise level up to 65 dB;
rich equipment and easy installation;
fault tolerance due to the absence of complex technical solutions and the use of reliable materials;
low price.

The manufacturing company has an extensive service network, however, users note that the pumps of the Gilex “Compass” series They break extremely rarely.

Pump Gilex "Compass" 25/60

4. DAB VA

A series of pumps from an Italian manufacturer is optimal balance of characteristics and price. They are not able to offer record performance, but they are reliable and adapted to the realities of domestic energy networks. The devices are characterized by:

three-stage speed adjustment;
simple installation using a quick-release connection;
two types of mounting dimensions: 130 and 180 mm;
noise level up to 70 dB;
affordable price.

Note! Today, the updated DAB VA line is presented on the market, where the issue of reliability has been carefully considered. A cast aluminum engine shell, technopolymer turbine wheel, ceramic shaft and thrust bearing, graphite bushings, many stainless parts and a new generation of EPDM O-rings are used.

Circulation pump DAB VB 55/120

Conclusion

Today you can buy any circulation pump on the market. In addition to those presented in the rating above, we offer adaptive systems, independently determining the parameters of the working fluid and changing productivity. The main thing for the user is to correctly calculate the required supercharger performance. And then, if you do not buy frankly junk products from the Chinese garage industry, a heating system with a high-quality pump will function for a long time, without fail and stably.

Pump installed in the heating system.

A wet rotor circulation pump is an element of the heating system designed to circulate coolant through the heating circuit.

Design

The pump device consists of a cast iron casing in which an electric motor rotates a composite wheel mounted on a shaft. The wheel consists of two disks, between which curved blades are located radially. The coolant enters the wheel through a hole in the lower disk.

In wet running models, all moving parts (including the motor rotor) are in contact with the coolant, which will act as a lubricant/cooler for the ceramic (graphite) end bearings and the rotor itself. In this case, the stator is isolated from the coolant using a metal partition with sealing gaskets.

The design of “wet” pumps is more complex than the design of pumps with a dry rotor, so their cost with equal characteristics will always be higher.

Note! As a rule, circulation pumps have 3 speeds, which are switched by turning the regulator to one of three speeds. At the same time, at minimum speed, the pump consumes approximately 2 times less electricity compared to maximum speed.

Installation

The installation of a circulation pump for a heating system, like any other heating equipment, must be carried out in accordance with the installation manual, as well as in accordance with the design of the heating system. However, some general requirements for installing a circulation pump can be identified:

The direction of movement of the coolant must coincide with the direction indicated by the arrow on the body;
The pump must be installed between the boiler and the heating circuit (but not between the radiators). It can be installed on both the supply and return lines, but preference is given to the return pipeline. The specific installation location must be easily accessible, because during operation, it may require maintenance or replacement in case of failure;
Do not place thermal insulation on the engine compartment;
After a circulation pump with a wet rotor, it is recommended that in case of an emergency, it will prevent the coolant from moving in the opposite direction;
Shut-off valves must be installed before and after the pump. In the event of a breakdown, the shut-off valves will allow you to remove/replace the device without draining the coolant from the system;
It is recommended to install anti-vibration inserts before and after it. This does not apply to small pumps;
After installation, the housing should not experience pressure from the connected pipes. When installing a circulation pump on relatively long pipelines, it is recommended to fix both the pipes themselves and the pump. This will reduce the negative impact of vibration;

Note! It is necessary to install a strainer in front of the pump, which will reduce the likelihood of damage to the mechanisms by various mechanical particles (sand, rust, scale or other sludge). In addition, its correct location will allow it to avoid contamination by such particles; it should not be installed in the lowest section of the heating system.

Installing a wet rotor circulation pump at the highest point in the system can result in air being frequently drawn into it. If, nevertheless, air has accumulated in it, it is necessary to slowly unscrew the air bleeder screw using a screwdriver or a coin and allow the coolant to flow out for 2-4 seconds;

To support the circulation pump for the heating system, it is prohibited to use wooden (or made from any other fire hazardous material) supports, because during operation, the housing can heat up to a temperature of +124°C, so such supports may catch fire;

Note! You should always remember that the body of a running pump heats up to high temperatures and there is a risk of burns if you come into contact with it.

If the heating system has just been installed, before operation it is recommended to rinse it with water at a temperature of 80-85°C, then drain the water and only then fill the system with “permanent” coolant. This will remove all contaminants that may have entered the heating circuit during installation work;
The motor shaft must always be in a horizontal position.

Wilo pump on the underfloor heating distribution manifold.

Electrical part

The electrical connection must be carried out by a trained specialist in accordance with the connection diagram, which is in the instructions and installation manuals.
The terminal box should not be directed downwards, because In the event of a leak, coolant may enter it. In addition, in this position it is inconvenient to maintain.
The pump must be grounded.

High noise levels during operation of a wet rotor circulation pump can be caused by:

presence of air;
low suction pressure;
too high coolant speed;
mechanical particles have entered moving parts.