Heating systems are divided into systems with natural (gravity) and forced circulation. In systems with forced circulation, the installation of a circulation pump is required. Its task is to ensure the movement of coolant through the system at a given speed. And in order for it to cope with its task, you must choose the right circulation pump.
Purpose and types
As already mentioned, the main task of the circulation pump is to provide the required speed of coolant movement through the pipes. For systems with forced circulation, only under such conditions will the design capacity be achieved. During operation of the circulation system, the pressure in the system increases slightly, but this is not its task. It's more likely by-effect. There are special ones to increase the pressure in the system.
There are two types of circulation pumps: dry and wet rotor. They differ in design, but perform the same tasks. To choose what type of circulation pump you want to install, you need to know their advantages and disadvantages.
With dry rotor
It got its name due to its design features. Only the impeller is immersed in the coolant; the rotor is in a sealed housing, separated from the liquid by several sealing rings.
The design of a circulation pump with a dry rotor - only the impeller is in the water
These devices have the following properties:
- They have high efficiency - about 80%. And this is their main advantage.
- Requires regular maintenance. During operation, solid particles contained in the coolant fall on the sealing rings, breaking the tightness. Maintenance is required to prevent depressurization.
- Service life is about 3 years.
- When working they publish high level noise
This set of characteristics is not very suitable for installation in heating systems of private houses. Their main advantage is high efficiency, which means lower energy consumption. Therefore, in large networks, circulation pumps with a dry rotor are more economical, and are mainly used there.
With wet rotor
As the name implies, in equipment of this type, both the impeller and the rotor are located in the liquid. The electrical part, including the starter, is enclosed in a sealed metal cup.
Wet rotor pump design - only the electrical part is dry
This type of equipment has the following properties:
- Efficiency is about 50%. Not the best indicator, but for small private heating systems this is not critical.
- No maintenance required.
- Service life is 5-10 years depending on the brand, operating mode and condition of the coolant.
- During operation they are almost inaudible.
Based on the above properties, choosing a circulation pump by type is not difficult: most people choose devices with a wet rotor, since they are more suitable for working in an apartment or private house.
How to choose a circulation pump
Each circulation pump has a set of technical characteristics. They are selected individually for the parameters of each system.
Selecting technical specifications
Let's start with the selection of technical characteristics. There are a lot of formulas for professional calculations, but to select a pump for the heating system of a private house or apartment, you can get by with average standards:
Selecting a circulation pump for heating following these rules is not difficult. Elementary calculations. But it must be said that these figures are statistical averages. If your house at some point differs greatly from the “average” indicators, you need to make adjustments either towards increasing or decreasing technical characteristics. For example, you have insulated your house well, but the power of the previously purchased boiler turned out to be excessive. In this case, it makes sense to choose a pump with a lower capacity. In the opposite situation - the house is chilly in extreme cold - you can install a more efficient circulator. It will temporarily solve the problem (in the future you will need to either insulate or change the boiler).
Model selection
When choosing a specific model, pay attention to the graph with the pressure characteristics of the pump. On the graph you need to find the point where the pressure and productivity values intersect. It should be located in the middle third of the curve. If it does not fall on any of the curves (there are usually several of them, characterizing different models), take the model whose graph is closer. If the point is in the middle, take the less productive one (the one located below).
What else to pay attention to
In the technical characteristics of circulation pumps there are several more items that are worth paying attention to. The first is the permissible temperature of the pumped medium. That is, the temperature of the coolant. In high-quality products this indicator ranges from +110°C to +130°C. In cheap ones it can be lower - up to 90°C (but in fact 70-80°C). If your system is designed as a low-temperature system, this is not a big deal, but if you have a solid fuel boiler, the temperature to which the coolant can be heated is very important.
It is also worth paying attention to the maximum pressure at which the pump can operate. In the heating system of a private house it is rarely higher than 3-4 atm (this is for two-story house), and normally it is 1.5-2 atm. But still, pay attention to this indicator.
Something else to pay attention to is the material from which the case is made. The optimal one is cast iron, the cheaper one is made of special heat-resistant plastic.
Connection type and size. The circulation pump can have threaded or flanged connections. The thread can be external or internal - appropriate adapters are selected for it. Connection sizes can be: G1, G2, G3/4.
It is also worth paying attention to the presence of protection. There may be dry-running protection. In circulation pumps with a wet rotor, it is very desirable, since the cooling of the motor occurs due to the moving medium. If there is no water, the motor overheats and fails.
Another type of protection is overheating protection. If the motor heats up to a critical value, the thermal relay turns off the power and the pump stops. These two features will extend the life of the equipment.
Manufacturers and prices
| Name | Performance | Pressure | Number of speeds | Connection dimensions | Maximum working pressure | Power | Housing material | Price |
|---|---|---|---|---|---|---|---|---|
| Grundfos UPS 25-80 | 130 l/min | 8 m | 3 | G 1 1/2" | 10 bar | 170 W | Cast iron | 15476 RUR |
| Caliber NTs-15/6 | 40 l/min | 6 m | 3 | external thread G1 | 6 atm | 90 W | Cast iron | 2350 rub. |
| BELAMOS BRS25/4G | 48 l/min | 4.5 m | 3 | external thread G1 | 10 atm | 72 W | Cast iron | 2809 RUR |
| Gilex Compass 25/80 280 | 133.3 l/min | 8.5 m | 3 | external thread G1 | 6 atm | 220 W | Cast iron | 6300 rub. |
| Elitech NP 1216/9E | 23 l/min | 9 m | 1 | external thread G 3/4 | 10 atm | 105 W | Cast iron | 4800 rub. |
| Marina-Speroni SCR 25/40-180 S | 50 l/min | 4 m | 1 | external thread G1 | 10 atm | 60 W | Cast iron | 5223 RUR |
| Grundfos UPA 15-90 | 25 l/min | 8 m | 1 | external thread G 3/4 | 6 atm | 120 W | Cast iron | 6950 rub. |
| Wilo Star-RS 15/2-130 | 41.6 l/min | 2.6 m | 3 | internal thread G1 | 45 W | Cast iron | 5386 RUR |
Please note that all specifications are based on water movement. If the coolant in the system is a non-freezing liquid, adjustments must be made. You will have to contact the manufacturer for relevant data for this type of coolant. It was not possible to find similar characteristics in other sources.
Circulation pump
A comfortable temperature inside a private house during the heating season is the key to comfortable living there. No one will argue with this. This means that the heating system must be given Special attention, Where important role Not only the heating boiler and radiators play a role, but also all other elements. That is, an integrated approach to solving this problem is common. Hence the responsible approach to such an element as the heating circulation pump. Of course, this is only necessary if the entire system is designed as a coolant injection type.
Hence several questions that often plague country homeowners who have this particular type of heating system in their homes. There are many questions, but there are a few main ones. Here are just a few of them. How much money do you have to pay for the electricity consumed by the pump? Do you have problems starting the circulation pump after a long period of inactivity? How often are heating pumps repaired? And so on and so forth.
But first, let's start answering the question below.
What is a circulation pump?
This is a small unit that is installed in the heating piping system and transports the coolant through all branches of the heating system, that is, it ensures circulation hot water. There is a wide variety of circulation pumps for heating systems, but for private homes, units with the so-called “wet rotor” are usually used. What is the design feature of this model?
The thing is that the moving parts of the pump, and this is mainly the rotor and impeller, are cooled and at the same time lubricated by the liquid flowing inside the pump, that is, the coolant. Hence the quiet operation, high reliability, and small dimensions of the unit itself. Let's add durability, efficiency and cost-effectiveness here.
The need for a circulation pump
Double equipment
As mentioned above, there are two types of heating systems: convection, that is, with natural circulation of coolant, usually this type is used in houses with an area not exceeding one hundred square meters, and injection, where the circulation pump is installed. The convection heating method with a large area of the house will not be able to ensure uniform distribution of coolant throughout all branches of the system, so there is a possibility that some radiators will not work efficiently. It’s just that the coolant will reach them poorly or with large heat losses, but simply cooled.
The pump creates the necessary pressure inside the system, which helps distribute the coolant evenly throughout the entire circuit and drive it at a certain speed, which does not interfere with the transfer of heat through the radiators. Therefore, when approaching the choice of a circulation pump, it is necessary to know exactly the parameters of the entire system, especially its hydraulic components.
How to choose a circulation pump?
In order to make the right choice, you must first determine all the parameters of the heating system, and how much heat will be needed to create comfortable living conditions in a private home. Such a complex calculation can only be done by a specialist who will take into account a large number of parameters and indicators:
- Climatic conditions of the region where the private house was built;
- What the house is built from, that is, the materials used. Here, walls, floors, ceilings, and roofing are taken into account.
- Insulation of the house - done or not.
- What windows are installed and their number.
- Home ventilation.
- And so on.
Types of equipment
As a result of collecting information and calculations, it is possible to calculate the exact volume of required heat supply, which is measured in cubic meters passed through the system in one hour (cubic m/hour). The circulation pump will be selected based on this volume. If the heating is being reconstructed, the unit is selected for a ready-made system.
A few words about silent operation. Typically, noise in pipes occurs for two reasons: the pump in the heating system is incorrectly selected or air pockets have formed inside it. In the first case, you will have to recalculate the pump parameters, but in the second, you just need to correctly approach filling the system with water. What needs to be done for this?
- The system is completely filled.
- Air is removed through air valves.
- The boiler turns on.
- The circulation pump turns on and should run for ten to fifteen minutes.
- Turn off the pump and remove air through the valves.
- Check the pressure inside the heating system and add water if necessary.
- Turn on the pump and adjust it.
Now let's return to the question about downtime and starting the unit. Long downtime does not in any way affect the quality of operation. One important thing to understand here is that sometimes sludge deposits collect inside the pump and need to be cleaned. How to do it? It's simple. The circulation pump has three rotor speeds, so to clean it it is necessary to turn on the unit at the maximum operating mode. In this mode, all deposits will quickly come out of it. If the pump is adjustable, then it is equipped with a release system that helps the model self-clean.
Materials used in the production of circulation pumps
This is a very important aspect that affects not only the quality of work, but also the cost of the unit. It is clear without words that contact of pump parts and assemblies with water brings a lot of trouble. Therefore, for the production of this type, high-strength materials are used that can withstand water with a fairly high temperature.
For example, today analogs are produced where the shaft, that is, the rotor, and bearings are made of ceramics. Such parts have high strength and a long service life. In addition, ceramics are not afraid of water. Plus, such parts work silently.
The average guaranteed service life of circulation pumps is at least ten years. Of course, the manufacturers' requirements here must be strictly followed, otherwise there are no guarantees. What do manufacturers require? Correct selection correct installation, prepared coolant, preventing some negative indicators in the heating system, for example, air inside.
Nuances and additional questions
Working device
It was said above that household heating circulation pumps have small overall dimensions. This is true. Manufacturers have achieved that with such dimensions pumps can effectively distill coolant through a fairly branched and long pipe system, where they are installed in large quantities radiators, boiler, boiler and other plumbing fixtures. Many may think that such a pump must consume a large amount of electricity. This is where many people go wrong.
The bulk of the units consume no more electricity than one incandescent light bulb. And among them there are also very economical models, the power consumption of which is six to eight watts. This is energy intensity. By the way, quite recently, manufacturers of circulation pumps came to a unified classification, which established a unified approach to designating products in accordance with power consumption. This is a type of household appliance. By the way, six-watt power fits category “A”.
The use of the “warm floor” system became the reason for the production of special circulation pumps for this type of heating. They are more powerful. This is due to the fact that in the “warm floor” system there are a large number of outlets in which the pressure or pressure of the coolant is lost. In addition, a small temperature difference is created here. It is also necessary to take into account the fact that in each room where heated floors are installed, it is necessary to install a separate unit. As you can see, this is quite a costly undertaking. Plus, in such systems, adjustable analogues must be installed.
Sometimes there are some really funny questions. Here is one of them: is it possible to install a regular water supply pump in the heating system of a private house? It is forbidden. Don't even think about it, although some models are very similar in appearance. Feed pumps can be used in a plumbing fixture or boiler feed system.
And one last thing. Heating systems with pump circulation are by far the most efficient. Here we mean not only the quality of heat transfer, but also the high efficiency of the entire system. And this means savings. This is what we are all striving for.
Until relatively recently, a heating pump in a private home was used very rarely. The boiler was located at the lowest point of the entire system, which made it possible for water to move through the pipes due to the laws of physics. Because of this, many residents of private houses often faced the problem of cold batteries. It arose due to insufficient fluid pressure in the heating system.
Everything changed after it became possible to purchase a pump for the heating system of a private home. When installed in water supply pipes near the boiler, it became much easier to speed up the passage of coolant through the pipes. This allowed for a more uniform heat supply.
How to choose the right pump for heating in a private home? What characteristics of the unit should you pay attention to? How to install the device after purchase? These issues will be discussed below.
Is it possible to do without a pump?
Is it necessary to install a heat generating unit? This question is one of the most common among owners of private houses. Of course, in cases where the total area of all premises does not exceed one hundred square meters, water can move through the pipes only due to its density and temperature. However, in Lately for installation heating systems We offer modern composite materials and pipes created on their basis. They are perfect for building multi-circuit systems, which are simply necessary in increasingly large private households, dachas and country cottages. In such cases, it is impossible to calculate and install a well-balanced system that would work only due to the principle of natural circulation. In addition, you should not build a similar scheme with previously used large-diameter pipes. It can be made as compact as possible, and a circulation pump can be installed to distribute heat evenly. Such a unit allows you to supply liquid to heating devices through small-diameter pipes, which are easier to hide in the wall of the house or behind a plasterboard partition.
Today, instead of cast iron radiators, which have been spoiling all our lives appearance rooms in our apartments, quite elegant aluminum or bimetallic ones are used. This significantly reduces the volume of water passing through the heating system, which allows the pipes to heat up much faster.
Connecting a pump to the heating system of a private home will reduce the temperature difference that occurs between heating devices. This will make the air warm up evenly in all rooms, creating comfortable conditions for the owners.
And, of course, the most important reason why you should install a circulating heating device in your house is to increase the efficiency of the system as a whole. And this will significantly reduce fuel consumption, the price of which is growing from year to year. It is worth keeping in mind that devices such as temperature controllers and thermostats, heated towel rails, as well as dehumidifiers and humidifiers simply cannot work without a circulation pump.
Device
What is a circulation pump? This is a technological device that operates in a ring heating system and constantly moves water through the pipes. Its main purpose is to ensure continuous movement of water and heat supply.
If we consider a simplified version of the unit’s design, then its operating principle lies in the interaction of the motor with the rotor, which is immersed in the coolant.
The running engine of the device continuously supplies liquid through the pipes. At the same time, the rotor converts kinetic energy into potential energy. This allows you to raise the pressure in the system to the required level.
Types of devices
How to choose a pump for heating a private house? In many ways, the reliable and high-quality operation of such a unit will depend on its type. The main classification is made according to the nature of the rotor's operation. In this case, there are dry and wet pumps. Let's take a closer look at them.
Dry ejectors
The main difference between such units is that their rotor does not come into contact with the liquid. This design allows the device to be provided with a mechanical seal classified as a sliding type. This allows the pump part to be isolated from the main mechanism. This design significantly extends the life of the device. It is usually used in pipelines, which are characterized by increased rate length.
Is it worth buying a similar pump for heating in a private home? In order to make a choice, you will need to consider the pros and cons of such units.
So, among him positive characteristics highlight:
High efficiency indicator, which reaches 85% at the output;
- long service life.
Among the disadvantages are noted:
The presence of sealing rings located between the motor and the rotor, which require replacement every three years;
- noisy operation, which will require installation in a separate room where the unit will not interfere with the normal rest of the owners;
- the need to control the cleanliness of the environment in which the device operates, since if atmospheric dust or dirt particles from the coolant enter, it can deteriorate.
Wet ejectors
Unlike dry ones, the rotor of such devices operates in water. There is an impeller on it, which accelerates the movement of liquid through the pipes. For the rotor of wet units, the coolant serves as a lubricant and coolant.
Is it worth buying such a pump for heating in a private home? Let's consider all the pros and cons of such units. Among the positive characteristics are:
Silence;
- no need for maintenance;
- ease of operation;
- durability;
- ability to adjust the intensity of work.
The only drawback is the low efficiency of the device. This figure does not exceed 50%. This makes it impossible to use wet pumps in thick or long pipelines.
Specifications
How to choose a pump for heating a private house? To do this, you will need to familiarize yourself with its technical parameters. This will not cause much difficulty, since there are only two such characteristics.
The first of these is pressure, that is, the hydraulic resistance of the entire system. This characteristic is measured in meters and represents the highest point of the pipeline.
The second important characteristic is the performance of the unit. The values of this parameter indicate the volume of liquid processed per unit time. Productivity is measured in cubic meters in an hour.
What should you keep in mind when purchasing heating pumps for a private home? Their characteristics are inversely proportional. For example, the electric pump will reach its maximum power at the zero elevation of the pipeline. The pressure will become as large as possible with the same flow.
When choosing pumps for heating a private home, their characteristics must be optimally suited to the existing system. At the same time, you should not adhere to the principle that the more productive the device, the better. Purchasing the wrong model will result in reduced heat transfer and increased energy use.
Extra options
In addition to pressure and performance, circulation pumps should be considered from several other points of view. So, attention should be paid to:
1. Permissible temperature of the pumped liquid. In the highest quality units, this indicator ranges from +110 to +130 degrees. A heating pump in a private house, the price of which starts at 5 thousand rubles, according to the instructions attached to it, can “pump” the coolant up to 90 degrees. In fact, this value is lower. It will be 70-80 degrees. If you plan to install a low-temperature system, cheap units will suit the owners quite well. When a solid fuel boiler is installed in the house, you need to purchase a higher quality device. After all, during its operation, the temperature of the coolant can be quite high.
2. The maximum pressure that the pump can withstand. If the heating system is installed in a private house, then this figure, as a rule, does not exceed 3-4 atm (this is applicable for a two-story building). Normally, pressure values range from 1.5 to 2 atmospheres.
3. Housing material. The most the best option Cast iron will be available for selection. Cheaper cases are made of heat-resistant plastic.
4. Connection size and type. The circulation pump may have flange connections or threads. The latter option will require the selection of appropriate adapters.
5. Availability of protection. What is this function? Some models provide protection for the unit from dry running. It is especially desirable in devices with a wet rotor. Indeed, in such devices the motor is cooled by a moving coolant, and if there is no water, it will overheat and fail.
6. The presence of a thermal relay. This part, installed in the pumps, protects the motor from overheating. When the temperature reaches its critical value, the thermometer immediately turns off the power and stops the pump.
7. Possibility of automatic operation. There are many similar settings, and their specific availability depends on the pump model. So, this could be the ability to automatically adjust the speed, an on/off timer, etc. Such devices have a control panel with which their operation can be configured, as well as switching from automatic to manual mode and back.
8. Availability of a display. This detail will allow the owner to get detailed information about the coolant temperature, pump operation, its current performance, existing failures, etc.
For those who prioritize the reliability and uninterrupted operation of the circulation pump, it is recommended to purchase a twin model. These are units with parallel connection two impellers. If one of them fails, the second will continue to pump coolant, even with less productivity.
Marking
Before you finally select a pump for the heating system of a private home, you need to familiarize yourself with the alphanumeric symbols on its label and decipher them. Typically, the marking of units indicates the following characteristics:
1.UP. These letters indicate the type of device. In this case it is circulating.
2. S/E. These letters follow the first ones and indicate the control method, which can be either smooth adjustment or stepped speed switching.
3. Numerical characteristics follow. Their first block indicates the internal diameter of the narrow pipes in millimeters. The second part is an indicator of the maximum pressure, which is expressed in decimeters. The third number block indicates the installation length in millimeters. This indicator is very important for inserting the device.
In addition to all of the above parameters, various manufacturers may provide additional information during labeling, including the following: method of connection to pipes, type of housing material, power of the device or its class, indicating the amount of electricity consumed.
Determination of technical parameters
How to choose a pump for heating a private house? First you need to decide on its technical characteristics. So, professionals, in order to decide how to calculate a pump for heating a private house, use a large number of formulas. If the unit is selected for an apartment or a cottage, then average standards are quite suitable.
So how to choose a pump for heating a private house? It is important to consider the following:
1. The performance of the unit is assumed to be equal to the power of the heating boiler in the house. In other words, if a 35 kW boiler is installed for the heating system, then in this case the pump should be selected with a capacity of at least 35 l/min.
2. At the next stage of choosing a unit, you will need to calculate the required lifting height (required pressure). How, in this case, are circulation pumps selected for heating private houses? On average, it is believed that for every 10 m of a pipeline a pressure of 0.6 m is required. That is, the lift height is determined by dividing the total length of the system by 10 and multiplying the result by 0.6. This is how a pump for heating in a private house is selected. The instructions for the device must contain a pressure value no less than that obtained in the calculation.
3. Comfortable conditions in the house can be created by changing the speed of water movement through the heating system. After all, only in this case will the owners have the opportunity to adjust the temperature depending on the existing weather conditions. In this case, the higher the speed, the more heat the liquid will transfer. Based on this best pumps for heating a private home - these are those that are capable of operating at different speeds. However, it is worth remembering that this parameter should not be higher than 1.6 m/s. This value is the threshold for silent operation of the entire circuit.
4. The power of the pump for heating a private house is selected based on the diameter of the pipes. Their smaller cross-section means greater hydraulic resistance. In other words, systems installed from small diameter pipes will require the installation of a more powerful pump.
Amendments made
Selecting circulation pumps for heating private houses using the above rules is not difficult. However, it is worth keeping in mind that the figures given are still statistical averages. A house may have various indicators that differ in one direction or another. It is worth taking this into account when calculating and making appropriate adjustments.
For example, the owners carried out work to insulate the house, and this led to the fact that the power of the already installed boiler became excessive. Installing a pump in the heating system of a private house in this case should have its own nuances. The unit should have lower productivity.
But the opposite situation is also possible. If the house is chilly and cold, then you will need to install a pump in the heating system of a private house with a more efficient capacity. For some time it will eliminate the problem, and then the owners must decide for themselves whether they will buy a new boiler or begin to insulate the walls of their home.
Installation of the device
Before water pumps are installed for heating a private home, the owner must decide on their location. The recommended area in this case is the section on the “return”, which is located in front of the boiler, but after the expansion tank. The latter prefers a calm flow of coolant. And if the pump is installed in front of such a tank, it will change the laminar flow passing through it to turbulent.
For ease of maintenance of the unit and to increase its service life when inserting, you will need to follow some rules:
Install Ball Valves on both sides of the device for ease of dismantling;
- install a special filter in front of the unit, which will become a barrier to small mechanical particles;
- provide a manual or automatic air valve on the upper section of the bypass path, which will help remove oxygen accumulated in it from the system;
- follow the installation direction indicated on the pump body, which may vary depending on the manufacturer;
- provide only horizontal insertion of the device into the heating system, which will allow it not to harm the engine during operation of the device;
- install the unit in such a way that its terminals always face upwards;
- treat all threaded connections and joints with sealants, as well as place a gasket between mating parts.
Purchasing a unit
What do those who decide to buy a heating pump for a private home need to know? The price of such a device will directly depend on its characteristics, power, brand or country of manufacture.
The cheapest options will be those that were released in China (from 3 thousand rubles). But, judging by consumer reviews, such devices have a short service life and are not very reliable. In order for the unit to work perfectly throughout the warranty period, it is worth considering well-known, time-tested brands of a European manufacturer.
The following units are considered the most reliable pumps for heating systems:
Wilo (Germany);
- Grundfos (Denmark);
- Valtec and Dab Pumps (Italy);
- “Dzhileks” (Russia) and some others.
The heating system of a small building is based on the natural circulation of a coolant fluid in the pipeline. For large objects with several floors, we use a forced or forced circulation method.
Circulation pump diagram
Circulation pumps are a type of highly specialized equipment. The main functional load of the unit is to ensure forced circulation of coolant in closed heating systems.
Internal organization:
- the body is assembled from metal parts with high anti-corrosion properties, for example, steel, brass, cast iron, bronze. The body has a connecting element - a snail. It is needed to connect to the circuit pipes;
- working part - rotor - ceramic or alloy steel;
- shaft with an impeller in the form of a wheel with blades. Needed for the process of coolant circulation along the circuit. On one side it sucks in water and on the other side it drives it through the system;
- energy source - electric motor with rated power for the model;
- The operating principle of the pump is that it creates a vacuum at the inlet and working compression at the outlet.
By design features circulation pumps for heating are divided into 2 classes:
- dry - the rotor is not immersed in water or does not come into contact with the coolant;
- wet or humid - the rotor is in half or full contact with the coolant.
Characteristics of the circulation pump
Each circulation pump model has certain performance characteristics that describe its functional features. The main indicators are pressure, productivity and flow. They are indicated in the technical passport.
The head or pressure of a circulation pump is usually measured in “water columns meter” or in atmospheres. The corresponding tables contain translations from one system to another. The pressure value is indicated by the manufacturer on a special tag attached to the pump body or in the technical data sheet for the unit.
- the pressure must be calculated for each building and room;
- a correctly selected pump should create optimal pressure, without large hydraulic losses in connections and pipes;
- Usually, a graph is attached to the model in the data sheet to determine the pressure and power;
- pump speed is selected. Then the required pressure is calculated as the sum of the hydraulic resistance of the system: all bends, turns of pipes, tees;
- the calculation of hydraulic resistance is made without taking into account the height of the structure, since the height of the water rise does not play a special role. In a closed system, the effect of communicating vessels occurs: the height of the supply line and the liquid column are balanced;
- For multi-storey buildings the hydraulic resistance of a closed system is assumed to be 2-4 m of water column or 0.2 - 0.4 atm;
- experts assume 0.6 m of pump pressure per 10 m length of the circulation ring.
For clarity, let’s look at the example of a Grundfos UPS 25-40 circulation pump. A well-known company for the production of power tools and units.
The marking contains 2 numbers. The first - 40, indicates the height of the coolant supply/lift, namely 4 m or 0.4 atmospheres. This is the determining value when choosing a pump for a particular system.
The second digit - 25 is necessary to determine the diameter of the pipes 1 inch or 25 mm. It is customary to use pipes with the same or slightly larger diameter, for example 1.25 inches = 32 mm. The values are standard. When choosing, it is worth considering the full marking of the pump; it must correspond to the diameter of the pipes and adapters of your heating system. On the circulation pump, it is necessary to indicate the power consumption for several modes, the speed of the rotor, the direction of its movement and the movement of hot water.
2. How to correctly determine the flow rate:
- the main determining factor is the magnitude of the heating load. To do this, you need to find a program for calculating the amount of heat using general indicators or calculating heat loss;
- You should not calculate according to European standards. Abroad they accept 100W/m2. For domestic houses it is better to take 120 or higher W/m2;
- formula for calculating G= (Q/(t2-t1))x103. Q is the heating load, it is taken according to the required amount of heat consumption chosen by you. G is the coolant flow in the system. t2 t1 - inlet and return water parameters, respectively. Temperatures are selected from a special temperature chart. Typically, the temperature in the t1 circuit is selected from 60 to 70 degrees. The t2 value is taken in the range from 90 to 95 degrees. The formula does not give an exact definition, but it will help you choose a pump with optimal parameters.
For non-specialists, the best solution is to use ready-made thermal standards. For example, to heat 10 m2 of a room of any height, 1 kW of boiler power is taken. One section of the radiator accepts 200 W. It turns out that to heat 10 m2 you will need 5 sections. Add 1-2 for stock. Next, the volume of all sections in each room is summed up - this will be the value G + 3-5%.
3. How to choose the power of the circulation pump, taking into account external factors
Calculation using formulas is an important process. However, formulas often do not take into account the influence of external factors on the performance and heating process. To make the adjustment, the following conditions must be taken into account:
- ambient air/medium temperature. She has big influence on the amount of heat produced when heating a home and, accordingly, on the efficiency of the pump. A “cold” unit always performs worse than a “warmed” one. The pump overheats when the maximum permissible load is exceeded. This happens when the influence of outside air temperature is removed;
- pipe diameter Users often consider pipe diameter to be the main optimal parameter for good heating. Larger diameter - more kcal. Large cross-section pipes require a powerful circulation pump;
- coolant viscosity. The use of a special coolant in a closed circuit affects the power of the selected pump. The viscosity of special liquids is always greater than the viscosity of hot water;
- frequency of circulation. The operating time of the pump must be taken into account: constant or periodic. To use the pump as auxiliary equipment replenishing the heating system, adjusting the pressure/pressure, requires a pump with low power. The circulation pump Willo N. O. - 25/4 is ideal for such purposes. It will provide a pressure rise from 1 to 5 m of water. Art.;
- presence of a double heating circuit. Often circulation pumps are installed to work in tandem with a natural circulation system. In this case, the load on the unit is assumed to be large. It is necessary to select a powerful pump, productive with high pressure.
Selecting a pump based on ease of use
Comfort refers to the characteristics of the noise emitted by the pump motor and the efficiency of electricity consumption.
The choice is made by comparing the main types of pumps: wet and dry versions.
1. “Dry” circulation pump.
Advantages of the units:
- internal working parts do not come into contact with the coolant. For this purpose, special sealing gaskets made of carbon agglomerate, high-alloy steel, ceramics, and aluminum are used. The rotor lasts longer long term than in “wet” pumps;
- The internal parts are carefully polished and ground together. Well-fitting O-rings prevent leakage of special fluid for the heating system;
- rings have a service life of more than 3 years. This is higher than the stuffing box, which requires seasonal maintenance;
- The efficiency of “dry” pumps is up to 80%. Indicator up to 0.8;
- Availability of models for horizontal and vertical installation.
Flaws:
- The main negative is the high noise level; installation in a residential area is not advisable. Typically, a separate soundproof room is allocated for the “dry” pump;
- applying ring lubricant;
- For pumps with sliding end rings, the quality of the coolant must be monitored. Eliminates the presence of suspensions and small particles in water;
- additional costs for maintenance and purification of the coolant.
2. Wet type pumps.
Advantages:
- no lubrication required for the shaft impeller. The working part of the unit is immersed in a coolant fluid, which immediately cools the engine and acts as a lubricant;
- the engine is packaged in a special sealed stainless steel container;
- the rotor is made of highly corrosion-resistant materials: ceramics, aluminum alloys;
- long working life;
- low noise level at the limit of audible tone. Some models produce no more than 25-36 dB;
- modular design of models. Easy to maintain units. The initial setup is performed even by a non-specialist;
- inexpensive units for replacing engine parts;
- wide range of installation of electric motors: one or three phase;
- compact design. The pump is installed in a hard-to-reach, narrow place;
- low prices for models.
Flaws:
- low efficiency. 30% less than dry type models. The indicator is not higher than 0.5;
- the impossibility of complete sealing leads to heat leakage;
- Most models require horizontal installation, which is not always suitable for the user.
3. Selecting a circulation pump for heating based on cost.
Various servers on the Internet and in reality offer to buy a circulation pump for heating according to certain parameters.
The cost of the pump depends on the manufacturer, performance and versatility. Withdraw average price possible within the line. For example, popular brands from Italy - DAB", "Lowara", "Ebara", "Pedrollo" will cost from $120 to $280.
A German Wilo circulation pump and a Danish Grundfos UPS circulation pump cost from $80 to $800.
The difference in price is explained by high-quality internal filling and expanded functionality. The price is affected by the power and performance of the pump. The more powerful, the more expensive.
You should not expect to find a model that 100% satisfies your needs. Each heating system has its own nuances and operating features. The pump is selected based on average calculated parameters.
Recently, experts have recommended installing Oasis circulation pumps made in China. The model has a compact design. A wide selection from the series line is offered. It is easy to select the unit that is optimal in terms of parameters and can be easily mounted on a horizontal surface. It has a low cost of $50.
How to choose a circulation pump. Reviews
1. User reviews are always on the pages with descriptions of models. Decide on a model, go to the brand’s page and analyze which reviews have the most. From experience we can say that only laudatory reviews are a marketing ploy. Real people always write about both the positive and the negative. They share operating experience and warn about hidden defects. Helps avoid maintenance difficulties.
2. Reviews left by experts carry the greatest weight. Professionals, more often than others, are faced with the installation, adjustment and repair of all branded circulation pumps. When choosing, contact a knowledgeable master. He will save you the hassle and find best option By technical parameters and on the part of financial expenses.
3. When choosing a model, you should familiarize yourself in detail with the manufacturer that produces the brand. Pay attention to the lifespan of the brand. She must be at least 3 years old. Age is important not only for image, but also for the availability of technical service. If unknown brands of pumps break down, they may not be accepted for repair in the workshop. The reason for failure will be: lack of original spare parts.
Advice from the master. When choosing a pump, consider all factors, but the ease of installation of the pump and simple maintenance should prevail.