How to calculate the pump for heating: examples of calculations and selection rules

A circulation pump is a small device, the main task of which is to improve the work and increase the performance of the heating system. It cuts directly into the pipeline, optimizing the speed of movement of the thermal medium. Due to this, even a house with a large living space will be heated quickly enough.

To buy the optimal model, it is necessary to figure out how to calculate the pump for heating and what nuances to navigate when choosing. Our article is devoted to these issues - in this material we looked at an example of calculating equipment, paid attention to the principle of operation and the main types of pumps.

We also gave recommendations on the selection, installation and safe operation of pumping equipment, providing the article visual and photo and suitable videos with the calculation of the required power of the device and tips for its installation in heating circuit.

The principle of operation and purpose of the pump

The main problem of the inhabitants of the upper floors of apartment buildings and owners of country cottages is cold batteries. In the first case, the coolant simply does not reach their homes, and in the second - the farthest sections of the pipeline are not heated. And all this is due to insufficient pressure.

When do I need to use a pump?

The only correct solution in a situation with insufficient pressure will be the modernization of the heating system with a coolant circulating under the force of gravity. This will help install the pump. Basic heating arrangements with pump circulation reviewed here.

This option will also be effective for owners of private houses, allowing you to significantly reduce heating costs. A significant advantage of such circulation equipment is the ability to change the speed of the coolant. The main thing is not to exceed the maximum permissible readings for the diameter of the pipes of your heating system, in order to avoid excessive noise during the operation of the unit.

So, for living rooms with a conditional passage of pipes of 20 mm or more, the speed is 1 m / s. If you set this parameter to the highest value, you can warm up the house in the shortest possible time, which is important in the case when the owners were away and the building had time to cool down. This will allow you to get the maximum amount of heat with minimal time.

The principle of operation of the device

The circulation unit is operated by an electric motor. He takes the heated water from one side and pushes him into the pipeline on the other. And from this side again comes a new portion and everything repeats.

It is due to the centrifugal force that the thermal carrier moves through the pipes of the heating system. The operation of the pump is a bit like the fan, only the air does not circulate around the room, but the coolant through the pipeline.

The body of the device is necessarily made of corrosion-resistant materials, and for the manufacture of the shaft, the rotor and the wheel with blades are usually used ceramics.

The main types of pumps for heating

All equipment offered by manufacturers is divided into two large groups: pumps of the "wet" or "dry" type. Each type has its advantages and disadvantages, which must be taken into account when choosing.

Wet equipment

Heating pumps, called “wet”, differ from their counterparts in that their impeller and rotor are placed in a thermal carrier. In this case, the electric motor is in a sealed box, where moisture can not get.

This option is the perfect solution for small country houses. Such devices are notable for their noiselessness and do not need careful and frequent maintenance. In addition, they are easily repaired, adjusted and can be used with a stable or slightly changing level of water consumption.

As for the shortcomings, the category indicated above is characterized by low productivity. This minus is due to the impossibility of ensuring a high tightness of the sleeve that separates the thermal carrier and the stator.

"Dry" type of devices

This category of devices is characterized by the absence of direct contact of the rotor with the pumped water heated by it. The entire working part of the equipment is separated from the electric motor by rubber protective rings.

The main feature of such heating equipment is high efficiency. But from this advantage follows a significant disadvantage in the form of high noise. The problem is solved by installing the unit in a separate room with good sound insulation.

When choosing, it is worth considering the fact that the “dry” type pump creates air turbulence, therefore small particles dust can rise, which will negatively affect the sealing elements and, accordingly, tightness devices.

Manufacturers have solved this problem like this: when the equipment is in operation, a thin water layer is created between the rubber rings. It performs the function of lubrication and prevents the destruction of sealing parts.

Devices, in turn, are divided into three subgroups:

• vertical;
• block;
• cantilever.

A feature of the first category is the vertical location of the electric motor. Such equipment is worth buying only if it is planned to transfer a large amount of thermal media. As for the block pumps, they are installed on a flat concrete surface.

Console devices are characterized by the location of the suction nozzle on the outside of the cochlea, while the discharge is located on the body with the opposite.

In more detail about the device and the principle of operation of the pumps we talked in this article.

What to focus on when choosing a pump?

Selection of the pump for autonomous heating should be done on the basis of the hydraulic characteristics of the heating system of a country house. Therefore, before visiting the store, it is necessary to calculate the optimal amount of heat that will be required to maintain a comfortable temperature in the rooms.

Competently perform hydraulic calculation will help additional information with which to be read. Or you can use the advice of a competent specialist.

The optimum amount of heat for a particular object is affected by many factors:

• the material that was used for the construction and insulation of walls;
• climatic conditions;
• features of floors and floors;
• the presence of thermostatic valves;
• characteristics of double-glazed windows installed in the cottage.

When choosing a pump for autonomous heating, special attention should be paid to the scope of application of a particular model, the number of speeds and the level of noise. Also, the manufacturer and the price of equipment play an important role.

Criterion # 1 - the scope of equipment

In most cases, experts advise installing heating pumps, the rotors of which are entirely immersed in a thermal carrier. After all, in addition to a small noise level, such units more successfully cope with high loads.

As a result, a system with “wet” equipment will last longer, will be easier to repair and will not require undue attention.

Give preference to models for the manufacture of which is used solid steel and bearings, and the shaft is made of ceramic. Their advantage lies in the service life, which is at least two decades.

If the choice fell on a “wet” type heating pump, then you need to consider that it should not be installed in the heating system of an open type cottage. Indeed, in this case, the heated water, which lubricates the mechanism, contains in its composition a variety of impurities.

For example, sand microparticles can clog the gap between the rotor and the stator, which will lead to an imminent breakdown of the pump.

As for open systems, in them such equipment can function for years. However, it will not need any specialized service.

Criterion # 2 - calculation of optimal power

The performance of the pump, designed to work in the heating system, can be calculated independently. To do this, you need the total length of the pipeline through which the equipment will pump the coolant.

For every 10 meters of length, we take 0.6 meters of the head of the device. So, for a small house with a heating circuit length of 70 meters you will need a pump with a pressure of 4.2 meters.

You can go the other way and calculate this figure by the formula:

Q = 0.86 * R / TF-TR,

Where:

• R - need of the room in heat;
• Tf and TR show the temperature of the coolant when fed into the system and at its outlet, respectively. It uses values ​​in degrees Celsius.

In European countries, two values ​​are mainly used as the R parameter: 100 W / m² - for a house where one or two apartments are located, and 70 W / m² - for apartment buildings.

The above method is only one of many ways to calculate the optimal power of a circulating pump. Only a qualified specialist can perform the most accurate calculations.

Criterion # 3 - the number of speeds and pump noise

The main feature of modern models of pumps is the ability to configure them. You can adjust the power by switching the speed of the unit.

Today, the most common model with three speeds. This allows for a quick cooling as quickly as possible to warm the living quarters, and in the case of warming to reduce the performance of the device, while saving energy.

If you need to buy equipment that produces the lowest possible noise, then a wet-type pump is the best choice.

In the case of installation of a unit with a “dry” rotor, during its operation, an extraneous sound arising from the rotation of the fan that cools the electric motor will be heard. Therefore, it is better to install such a device in a separate room, and for a residential one to choose something less loud.

Not always extraneous noise that appears at startup, indicates a malfunction. Quite often this is due to the air that has remained in the heating system. To solve this problem it is recommended before running let the air out with special valves.

Criterion # 4 - manufacturer and price of equipment

After all the necessary calculations have been made, you can start browsing the catalog with circulation pumps. It is better to place an order on those web resources where there is a well thought out product filtration system. This allows you to quickly find models with optimal performance.

In the current market offers a rich selection of pumps for heating systems. Hundreds of manufacturers say that their products are distinguished by reliability, quality and durability. But not always the stated characteristics correspond to real ones. Therefore, it is better to order equipment manufactured by manufacturers who have declared themselves to the whole world.

The list of well-known and reliable companies engaged in the production of pumps for heating systems, should include the following brands:

• Halm;
• Wilo;
• Ebara;
• DAB;
• AlfaStar;
• Pedrolo;
• Grundfos.

The cost of units for the organization of forced transfer of coolant depends entirely on power, type of pump and brand. As a rule, the price of equipment varies in the range from 60 to 220 dollars. We recommend to get acquainted with the ten best pumps on heating according to users.

As for domestic manufacturers, they do not manufacture household equipment, and offer only models intended for use for industrial purposes.

Features of the installation of the circulation pump

To ensure the effective operation of the heating system at home, it is necessary to choose the right place in the heating ring to install the equipment. It is recommended to find the area where an excess water pressure is always observed in the area of ​​suction of the heat carrier. There are several methods by which this condition can be artificially achieved.

The first way is to raise the expansion tank by 0.8 m relative to the highest section of the pipeline. This can be realized only in the house where the ceilings allow it. A good solution would be to install an expansion tank in the attic. But in this case, you will have to do roof insulation to avoid unnecessary heat loss.

The second method is to transfer the tube from the supply riser from the expansion tank and insert it into the place where the pump suction nozzle is located nearby. Due to this, you can create just perfect conditions for organizing the forced transfer of hot water in the heating system at home.

Detailed recommendations for installing the pump, piping and step-by-step installation instructions are given. in the next article.

Rules and nuances of equipment operation

The circulation pump is not bought for a year or even two. Therefore, every owner of a country house should take care to ensure that the equipment is working properly for many years. To achieve reliability and correct operation of the device is possible only in the case of proper and timely service.

The following aspects should be included in the list of basic rules for operating a heating pump:

• It is forbidden to turn on the device with zero flow;
• make sure the equipment is grounded;
• check that the electric motor does not heat up above the permissible rate;
• check the connection in the terminal box for the presence / absence of damage, and all cables must be completely dry;
• make sure that during the start of the device there is no extraneous noise or vibration;
• the equipment should work with the coolant flow rate recommended by the manufacturer;
• It is forbidden to run the circulation pump without water.

If the equipment is idle for a long time, then it is recommended to turn it on every 10-30 minutes every month. Such a simple rule will help to avoid oxidation and, as a result, shaft locking.

Special attention must be paid to temperature. heat carrier. It should not exceed 60-65 degrees Celsius. If we neglect this rule, then sediment will appear in the pipes and inside the pump, which will negatively affect the operation of the entire heating system.

Often encountered breakage

The most common problem, due to which the equipment providing forced transfer of coolant, fails - it is its long simple.

Most often, the heating system is actively used in winter, and in the warm season it is turned off. But since the water in it is not very clean, then over time in the pipes precipitates. Due to the accumulation of hardness salts between the impeller and the pump, the unit stops working and can fail.

The above problem is solved quite easily. To do this, try to start the equipment yourself by unscrewing the nut and manually turning the pump shaft. Often this action is more than enough.

If the device still did not start, then the only way out would be to dismantle the rotor and subsequent thorough cleaning of the pump from the accumulated sediment of salts.

Conclusions and useful video on the topic

About the calculation of the performance of circulating equipment tells the video:

Proper installation is the key to excellent work of any device. Features of installation of the pump for heating in the video:

The heating system, where a pump is used to organize the movement of the coolant, has many advantages. But in order to correctly install it, you will have to spend some time analyzing the nuances and choosing the equipment. Only in this case, you can make your home truly warm and cozy..

Do you want to add a pump to the heating system, but doubt the calculations? Ask your questions in the comments block - our experts will try to help you.

Or maybe you want to supplement our material with useful comments? Or offer another option to calculate the heating pump? Write your comments and recommendations under this article.