Recirculation pump - device, operating principle, purpose, control options, types, selection, installation

Often, autonomous heating equipment is used to heat a private home, and a boiler is used for hot water supply. The only way in this case to minimize the time it takes to move heated water, thereby increasing the efficiency of the systems and avoiding heat loss, is a recirculation pump, correctly installed in the pipeline. Let's look at what it is, what its structure is, its operating principle and purpose, what control options there are, what types it is divided into, as well as how to select and install it correctly.

Recirculation pump in the hot water supply system of a house Source masteravannoy.ru

Device, principle of operation, purpose

Pumping equipment for pumping heated water through a closed pipeline loop in a private house is small in size and consists of the following main elements:

1. Housing made of stainless steel, cast iron or bronze and brass.
2. A stator that can withstand heating of the pumped medium up to 60-700C.
3. A rotor shaft with an impeller, the rotation of the blades of which ensures the injection of water into the pipeline.
4. Thermoplastic impeller.
5. Squirrel cage steel rotor.

At the same time, the pump is able to exhibit the characteristics laid down in it by the manufacturer, provided that the pumped liquid is technically clean - with a viscosity characteristic of water without the inclusion of mechanical impurities. The device is installed quite simply - without removal from the system, but by inserting it into a pipeline section. Therefore, the use of a bypass is not necessarily necessary.

The principle of operation of a recirculation pump for domestic hot water or heating boils down to the following mechanism:

• Water from the pipeline enters the device into the central part of the impeller.
• An electric drive rotates the blades.

Design of a circulation pump for hot water Source eurosantehnik.ru

• As a result, the resulting centrifugal force pushes water to the outlet pipe, giving the flow a given pressure.
• In this case, an increased injection of incoming water occurs at the entrance to the pump - due to the vacuum created on the back side of the blades.

The use of such equipment is not necessary for the operation of an autonomous water heating system, but it can significantly increase the efficiency and cost-effectiveness of energy consumption. If under normal conditions it takes time for hot water to come out of the tap when opening (since with a slow flow it cools quickly), then when using a pump it flows almost instantly.

This is especially true when the consumer is located at a relatively large distance from the water heater. Another useful function for which this type of recirculator is intended is the return of unused heated water to the heater via the return line. In addition, with a gravity-flow system, the farther the consumer is located, the more noticeable the initial pressure drops.

Option for placing a circulation pump in a heating and hot water system for a private home Source s-proms.ru

The use of a recirculation pump allows you to get rid of this significant drawback. This ensures constant water temperature and pressure at any point in the heating system or DHW circuit - regardless of the distance to the unit.

Important! Only a specially designed pump can be installed in a domestic hot water or heating system. A conventional centrifugal model for pumping water is not suitable, since it is not designed to work in an environment with elevated temperatures and will quickly deteriorate.

Manufacturers and prices

Despite the wide range of pumps in stores, it is not easy to choose a truly high-quality product. The market is flooded with Chinese goods and counterfeits of famous brands. First, let's list the popular manufacturers in the CIS:

1. The highest price category is Grundfos (Denmark), Wilo (Germany). Prices for original “Germans” start from 75 euros, “Grundfos” UPS series – 65 euros.
2. Middle category – DAB, Aquario (Italy), Sprut (quality China). The cost of units of various models ranges from 40-100 euros.
3. Other cheap pumps (Oasis, Neoclima, “Whirlwind”, “Caliber” and so on ad infinitum). Price – from 20 euros per piece.

The latest development is the Grundfos Alpfa-3 “smart” pump, which transmits information to a smartphone and helps balance the system

Comment. It is likely that we did not include some very worthy products in the highest or middle price category. The most common brands are listed here.

What is the difference between inexpensive and counterfeit pumps and high-quality superchargers:

• service life – 1…3 heating seasons;
• The product number is only on the sticker, the unit body is clean;
• pumping devices from the same batch often come with the same numbers;
• the weight of the fake is noticeably different from the original (it is lighter);
• A low-quality unit begins to make noise and squeak after working for 1 season in a closed heating system, and the housing gets very hot.

Sometimes counterfeit heating pumps are indistinguishable from the original, only the price is half the price. The secret is in the aluminum winding, which reduces the cost of the product. How to check: find a lot of the original model on the company’s official website and compare it with a market copy. Most likely, an informed seller will refuse to weigh a counterfeit device or will immediately recognize the unknown origin of the product.

Control options

Hot water in a private house is used periodically - for washing, washing, cleaning, showering, etc. There is no need to constantly maintain it in the DHW circuit. In addition, such an approach would lead to extremely wasteful consumption of energy resources and equipment.

Circulation pump with temperature sensor Source prom.st

See also: Catalog of companies that specialize in water supply, sewerage and related work

Therefore, in order for the heated water to reach the tap at the right time, 2 special pump control options are used - these are:

• Thermal sensor.

The principle of operation is based on maintaining a given water temperature in the circuit and boils down to the following algorithm:

1. The temperature-sensitive element is immersed inside the pipe and is in direct contact with the water.
2. As soon as the temperature inside drops below the set value, the sensor instantly sends a signal to the control module.
3. The recirculation pump starts and begins to supply hot water to the DHW circuit.
4. As soon as the heating level reaches the required value, the pump turns off.

To reduce energy consumption and equipment resources, the pipeline is specially thermally insulated.

• Timer.

Timer operation differs from the above option in that hot water is pumped into the pipes according to a specific schedule. This approach is convenient when it is known exactly during what specific period of time the hot water supply will be used. For example, on weekdays these are the morning and evening hours, when household members get ready for work and come back from it.

Circulation pump with timer Source cok.ru

Modern smart timer models allow you to set up a schedule several days in advance, as well as independently monitor the water consumption schedule and then automatically set the operation of the equipment. In addition, they are able to take into account the parameters of the hot water circuit - the length of the pipes, their capacity, the percentage of heat loss, the cooling time of the water - and, based on this, adjust the time the device is turned on/off.

Content

1. Kinds
2. Advantages and disadvantages
3. Rating of the TOP 7 best circulation pumps Grundfos UPS 25-40 180
4. VORTEX CN-25-6
5. Gilex "Compass" 25/40
6. Grundfos ALPHA2 25-40 180
7. WCP 25-80G
8. DAB EVOTRON 40/180
9. DAB A 110/180XT

Varieties

Hot water recirculation pumps are classified according to several criteria. First of all, they are divided according to their purpose in a closed loop circuit into 2 types:

1. The servers. Mounted on a direct line for supplying water from the heater.
2. Reverse. Installed on the return branch to return cooled water to the heating circuit.

Based on the type of design, pumps are divided into 2 types:

• With wet rotor.

The working part of the device is located directly in the pumped medium. Therefore, both cooling and lubrication of the device is carried out by the pumped liquid, in this case water.

Recirculation pump with a wet rotor Source teploufa.ru

Comparison table of the presented models

All of the above technical parameters of each model are presented in the table.

Selection rules

In order to choose the right circulation pump for domestic hot water, it is necessary to take into account the following number of criteria:

• Performance. The value is determined by the amount of water pumped per unit of time. For example, for a private house with an area of ​​100 m2, a model of 80-110 liters/min is optimal.
• Pressure The indicator depends on the location of the water heating installation and the height of the consumer relative to it. So, if the boiler is located in the basement, then a tap on the 2nd floor will require a value of this characteristic of 6-8 m.
• Power consumption. The stronger the motor, the more productive the device will be, but also the more expensive it will cost to operate.
• Control method. By timer or temperature sensor.
• Manufacturer's brand.
• Price.

A circulation pump for a home is selected based on several parameters at once Source byreniepro.ru

Important! Pump selection should be carried out by an experienced designer based on specific application conditions. This takes into account the number of intake points, the minimum and maximum volume of water used, the supply height, and the length of the pipeline.

How to choose a circulation pump

When choosing a circulation pump, experienced sellers and craftsmen recommend paying attention to the main characteristics:

1. Pump performance. The indicator is selected according to the power of the heating boiler, for example, if it is 40 kW, then the optimal pump capacity is 40 l/min.
2. Lift height or pressure. This is the second most important criterion when purchasing. When choosing equipment, it is customary to calculate the required pressure using the formula: 0.6 m of lifting height per 10 m of main line. Thus, for 50 m of heating system pipeline, a model with high performance and a pressure of at least 30 m is needed.
3. Flow speed adjustment. The speed control function is very useful; by changing it, you can control the intensity of space heating. There are two adjustment options: automatic, when the electronics independently changes the speed, and manual, which has 2-3 positions.
4. Engine power. If the heating pipes are narrow, the indicator should be higher, otherwise the power will not be enough for uniform and efficient heating
5. Form factor. Craftsmen always recommend choosing standard models, without various proprietary and design features that can complicate installation.
6. Brand. Today the market is crowded with various brands and manufacturers of pumping equipment, but many of them are very negligent in the build quality of the materials used. It is better to take models from well-known, reliable companies with a good reputation and a large network of service centers.

Video description

Video review of what a DHW recirculation system is and the rules for choosing a pump for it:
In this case, the standard installation procedure in the DHW circuit of a private house is carried out according to the following algorithm:

1. Assembling the device in accordance with the technical documentation.
2. Determining the installation location in the circuit.
3. Shutting off the feed.
4. Cutting out part of the pipeline at the installation site.
5. Connecting the device.
6. Sealing and checking joints for leaks.
7. Turning on the water supply, connecting equipment.
8. Configuration and performance testing.

Advice! To facilitate equipment maintenance and maintain maximum system functionality, it is best to install the device in a so-called pocket. This is a special outlet separated from the pipeline by shut-off valves. If necessary, the pump can be quickly turned off and dismantled, replaced with a new one or repaired - without stopping the coolant.

Best lists

In addition to the previously mentioned models, we recommend paying attention to the following pumps:

• Cheap - VORTEX TsN-32-6.
• Energy saving – UNIPUMP LPA 25-60.
• Quiet operation - Wilo Star-RS 25/4-180.

We invite you to familiarize yourself with their parameters and brief information.

Cheap – VORTEX TsN-32-6

One of the most tempting purchases: excellent technical parameters and a fairly affordable price. The device is considered one of the most affordable options with such excellent characteristics.

High motor power (90 W) allows you to create a pump lift height of up to 7.5 meters, maintaining a productivity of 9 m³/h. The device is made of high-quality cast iron, so this is also reflected in the weight of the device (3.8 kg). In general, buyers were satisfied with this pump, often leaving positive reviews on the forums.

Cost: from 2070 to 3199 rubles.

pump for heating system VORTEX TsN-32-6

Energy saving – UNIPUMP LPA 25-60

UNIPUMP LPA 25-60 is a more budget-friendly analogue of Grundfos ALPHA2. A model with a lot of advantages: 5 operating modes, no overheating, low noise level (only 43 dB), ease of use, as well as a high level of protection according to the IP42 standard.

Price: from 5426 to 10761 rub.

heating pump UNIPUMP LPA 25-60

Quiet operation – Wilo Star-RS 25/4-180

The quietest pump on the list is the best - Wilo Star-RS 25/4-180, the noise level of which does not exceed 34 dB. It is in great demand due to its efficiency (the device absorbs only 48 W) and efficiency - the technical characteristics speak for themselves. The pump looks very reliable: durable cast-iron body, stainless shaft - this model will definitely serve for years, with proper use. The only negative is that it can only be installed horizontally.

Price: from 4570 to 10108 rub.

pump for heating system Wilo Star-RS 25/4-180

Briefly about the main thing

A hot water circulation pump consists of a housing, a rotor, a shaft with blades, a stator and an impeller. The principle of its operation is that water flows through the inlet pipe to an impeller rotated by a drive. As a result of the resulting centrifugal force, the flow is injected and exits with a given pressure into the system. Thanks to the pump, the water does not have time to cool down in the pipeline and does not lose pressure, regardless of the distance of the tap from the water heater.

Such a pump can be controlled in two ways - by a temperature sensor and by a timer. In the first case, the supply is resumed when the water in the circuit cools, in the second - according to a schedule. Pumping equipment is classified according to several criteria:

1. Installation location in the diagram - supply and return.
2. Design type - with wet and dry rotor.
3. Number of drive speeds.

When choosing a pump, you need to take into account performance, pressure, power consumption, control option, brand, cost. Installation into the pipeline diagram is carried out depending on the purpose and strictly according to a given algorithm.

Which brand pump to choose

Circulation pumps are produced by almost all brands specializing in tools and various equipment. But experts ranked only 5 companies as the best:

• Grundfos. The Danish manufacturer of pumping equipment has been producing equipment for almost 100 years. The annual output of Grundfos products is 16 million, and it is supplied to 56 countries around the world. A special feature of the brand is its attention to the quality of all materials used in production, as well as careful quality control.
• Vortex. The company is a subsidiary manufacturer of the legendary Resanta brand. The company quickly gained popularity and is rightfully considered the best among budget brands.
• Wilo. The German brand was founded in 1872 and is one of the oldest manufacturing companies specializing in pumping equipment. Wilo has a wide selection of high-quality, technologically advanced pumps with a long service life.
• DAB. All types of pumps are produced under the brand: circulation, drainage, centrifugal and others. The brand also offers to purchase control units and industrial-grade equipment - fire stations, swimming pools. Along with European companies, DAB is famous for its quality and innovative approach to development.
• Wester. Inexpensive but reliable pumping equipment for heating systems is produced in Russia, in fully automated factories. The brand is a regular participant in exhibitions in different countries, which has allowed it to quickly achieve popularity and recognition. The company is well known in Russia and is represented in most stores.