Not so long ago, when purchasing high-quality pumping equipment for an autonomous heating system in a private home was a huge problem, preference was universally given to schemes with natural coolant circulation. However, despite the apparent simplicity of this approach, such systems are not highly efficient and economical. In addition, the possibilities for accurately adjusting the temperature in individual rooms of the house are significantly limited, and with many modern heat exchange devices and systems, this type of organization of coolant transfer is not at all possible.
And the declared ease of installation of a scheme with natural circulation is also very conditional, since obligatory observance of the slope, a strictly specified arrangement of devices is required, and the pipes themselves must be of increased diameter. Sometimes, in the conditions of a particular building, compliance with all existing mandatory conditions to ensure normal circulation becomes a difficult or even impossible task. All of these problems can be solved by installing a pump in the heating system of a private home.
It is this block of questions that will be considered in this publication. It can be divided into several main subsections:
- Why do you need a circulation pump, and what are the benefits of installing it?
- How does a circulation pump for a heating system work?
- How to choose the optimal model?
- Where is the best place to install?
- How to carry out installation work yourself?
Prices for circulation pumps for heating
circulation pumps
Advantages of a heating system with forced circulation of coolant.
Ardent supporters of heating systems with natural coolant circulation cite a number of seemingly irrefutable arguments in favor of just such a scheme.
- The pump is an extra cost for purchase and installation.
- Any electrical equipment becomes an additional consumer of expensive electricity.
- The dependence of pumping equipment on the stability of the power supply makes the heating system extremely vulnerable in emergency situations in the power grid.
- The pump is an additional component of the system, vulnerable from the point of view of mechanical breakdowns.
It would seem, at first glance, that everything is fair. But if you look at each point impartially, the picture changes literally to the exact opposite.
Let's look at the diagram of a heating system with natural circulation:
Is such a scheme so easy to install and cheap? Not at all!
From the boiler (item 1), it is imperative to install an accelerating vertical section (item 2), from a large diameter pipe - preferably 1½ inches or even more. At the same time, it must reach the highest possible point - above any heat exchange devices. There, at the maximum height, you will have to install an open-type expansion tank (item 3).
The supply manifold (item 4) must be located with a mandatory slope of at least 5% (5 cm for each linear meter of the contour). In this case, again, the diameter of the pipe should not be less than 1¼ inches.
Vertical risers (item 5), through which the coolant is supplied directly to the heating radiators (item 6), are made of pipes with a diameter of at least ¾ inches.
Finally, the requirements for the diameter and compliance with the slope of the “return” collector (item 7) are the same as for the supply pipe. It turns out that in any case the boiler should be located below the lowest radiators.
In a small building with compactly located rooms, this approach is still feasible, and even then not always. Large diameter pipes are not only much more expensive, but also more difficult to install. They are extremely difficult and often impossible to hide without spoiling the interior. The possibility of hidden bottom connections of radiators is almost completely eliminated. The cost of the pump itself and its installation (which can be done independently) is simply not comparable with the costs listed above.
Even with the most thoughtful, optimal placement of all elements of a natural circulation circuit, it is unlikely to realistically create excess pressure in it only due to temperature changes and differences in density above 0.6 atmospheres. But such a pressure will clearly not be enough for many modern heating devices. Moreover, you don’t even have to harbor plans to create a water floor heating system.
Moreover, even a minor blockage, somewhere on the bends of pipes or in another area vulnerable to this phenomenon, can completely paralyze the movement of coolant through the pipes. And this will be all the more likely if the system is sufficiently branched, since hydraulic resistance will also have its say.
In order for a system with natural circulation to reach its design capacity, a powerful starting energy “impulse” is required. These are extra energy costs, and quite considerable ones at that. Well, even a short-term shutdown of the boiler for one reason or another will require some effort and a lot of time to bring the heating system back to normal operation. The low speed of the coolant and the consumption of part of the energy generated by the boiler only for its movement is a general decrease in the efficiency of the entire system. And, believe me, these extra energy costs will certainly exceed the total consumption of a compact circulation pump operating with a constant load.
Low circulation speed also means clearly uneven heating of heat exchange devices installed in such a circuit and distributed throughout the rooms. Adjusting the level of heat transfer from radiators installed in the premises of a house becomes possible solely on a quantitative basis, that is, by changing the volume of liquid passing through the devices. This method is not accurate, and in conditions of low pressure in the pipes it can even lead to blocking of a particular radiator or section of the circuit. To talk about high-quality regulation in such conditions, that is, with the addition of coolant from the return, is generally naive.
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The result is the same - the inefficiency of the system directly negatively affects the efficiency of energy consumption, that is, it leads to unnecessary costs during the entire period of heating operation. It’s more profitable to spend money on a pump once...
Finally, a few words about the vulnerability of pumping equipment from the presence of power.
This is true, but in exactly the same way all electrical appliances in the house are dependent. Including - and the majority of modern heating boilers equipped with automation. The problem is solvable - it is enough to install an uninterruptible power supply for the boiler equipment.
With low pump power consumption, not even the most expensive and powerful UPS is able to keep the equipment running for several hours. This is quite enough.
And, finally, nothing prevents you from installing the pump so that in emergency cases it remains possible to switch to natural circulation in the system. This is what they usually do - the pump piping circuit includes a bypass (jumper) and several valves (an automatic valve can also be used).
Well, about the fact that the pump becomes another vulnerable link in the system. You can reassure the reader: statistics show that the failure of circulation pumps refers more to casuistic situations, they are so rare. The designs of devices from leading manufacturers are distinguished by excellent reliability and can serve for decades, unless, of course, the rules of operation are violated. And the resulting benefit in the form of economical operation of the system justifies the purchase of even an expensive pump within two to three years. So from this side there is the least amount of “expecting a catch.”
We hope that the reader is convinced of the need to install a circulation pump. So, it's time to consider how to choose it correctly.
How to choose the optimal circulation pump
Two main types of circulation pumps
Circulation pumps are devices powered by electricity. But direct contact of the electrical part with the hydraulic part is unacceptable. This division is provided by two approaches to the arrangement of devices, which predetermines their subdivision into “dry” and “wet” type devices. Much becomes clear from the title.
- Dry rotor pumps appeared earlier than their counterparts. Their principal scheme is such that the electric drive is completely isolated from the pump part, and the rotation is transmitted to the impeller through the shaft. Even externally, such pumps can be distinguished by their elongated body, due to the remote electric motor unit. As a rule, such devices are quite massive, so their console installation is most often practiced - for this purpose, brackets or mounting platforms are provided on the body.
Dry-type circulation pumps are powerful and efficient devices that provide both a very high flow rate of coolant passing through them and high pressure levels in the system. It's hard to do without them. If you are designing a powerful boiler room, for example, for a large mansion with several floors. But in the conditions of a medium-sized apartment or private house, their use already seems excessive, especially since they have certain disadvantages.
— The difficulties associated with the size, massiveness and installation features have already been mentioned.
— The shaft transmitting rotation has a complex system of seals that prevent leakage of liquid under pressure. These seals gradually wear out, which predetermines the need for regular preventative maintenance, including replacement with new ones.
— The operation of such pumps is always accompanied by a noise effect due to the need for air cooling of the electric drive. This also imposes restrictions on the choice of installation location for the device.
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In a word, if the heating system does not require specifically high pressure and coolant flow rates, the best option would still be to purchase a pump with a “wet rotor”.
- Pumps with a “wet rotor” are designed differently. The circuit diagram is shown in the illustration below:
The housing of the power unit (item 1) is hermetically connected, due to ring gaskets, to the body of the pumping working chamber (item 2) using several screws (item 3). On both sides of the “snail” working chamber there are certain fastenings for cutting into pipes - these can be threaded pipes (item 4) for a coupling connection or flanges.
Inside the power block there is a stator winding (item 5) - this is the only compartment that does not come into contact with the liquid medium - it is hermetically separated from all the others by a stainless steel “glass” (item 6). Thus, the seals are placed exclusively on static parts, that is, they do not wear out from friction.
Inside there is a rotor (pos. 7), onto the shaft of which the pump impeller (pos. 8) is rigidly mounted. The rotor rests on bearings, which receive constant lubrication from the coolant. The liquid medium that fills the entire internal space of the pump is also an excellent heat remover, and the device is not in danger of overheating and does not require an additional engine cooling system. To ensure that the entire volume of the pump is completely filled with coolant, a special plug (item 9) is provided for releasing air.
Rotation of the pump rotor in a liquid medium certainly entails certain energy losses, that is, a decrease in the efficiency of the device. But against the backdrop of low electricity consumption, this factor does not seem worthy of special attention - due to the insignificance of losses.
The operation of the pump is almost silent, the device is compact and easy to install - it simply cuts into the desired section of the pipe, without requiring any additional fasteners. True, in this case an important condition must be met - the rotor axis, regardless of the position of the housing, must take a horizontal position. In this position, the bearings will never be dry, and they are not in danger of failure due to overheating.
One more detail - do not allow solid suspensions, which may well form in the system circuits, to get into the bearings. Therefore, it is always recommended to install a mechanical cleaning filter – a “dirt filter” – directly in front of the pump.
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Criteria for evaluating a circulation pump when choosing
When choosing a circulation pump for installation in an existing heating system, it is necessary to take into account a number of criteria.
- Supply voltage. On the scale of autonomous heating systems for apartments and private houses, pumps with single-phase power supply 220 V 50 Hz are used. Low current consumption eliminates the need to lay any dedicated power lines - network sockets are sufficient. The only thing that is advisable to provide is uninterrupted power supply, which was mentioned above.
- Power consumption. Naturally, the lower it is (while maintaining other performance characteristics), the more economical the device is. The optimal choice would be a device of energy consumption class “A”, even if it costs more. The lower the class (“B”, “C” and so on), the greater the energy consumption.
Most modern pumps have the ability to select one of two or three operating modes, with different levels of pressure generated. In accordance with this, the power consumption also changes. Typically, the indicators are displayed on the device nameplate, in the form of a plate.
Since we have touched upon the issues of purely operational characteristics that affect the operation of the heating system - productivity and the pressure created, it makes sense to consider these indicators in more detail.
There are tables that can be used to approximately determine the required parameters - one of them is located below.
| Total floor space | Required thermal power (kW) at the difference in coolant temperatures in the supply and return pipes (Δt) | Pump parameters, min (without taking into account the hydraulic resistance of the circuits and their branching) | |||
|---|---|---|---|---|---|
| Δt= 20 °С | Δt= 15 °С | Δt= 10 °С | Productivity (m³/hour) | Head (m water column) | |
| up to 200 | 28,0 | 21,0 | 14,0 | 1,25 | 1,0 |
| 350 | 46,0 | 35,0 | 23,0 | 2,0 | 2,0 |
| 500 | 70,0 | 52,0 | 35,0 | 3,0 | 2,0 |
| 900 | 116,0 | 87,0 | 58,0 | 5,0 | 3,0 |
| 1100 | 140,0 | 105,0 | 70,0 | 7,0 | 3,0 |
| Δt= 20 °C - optimal mode for heating radiators | |||||
| Δt= 15 °C - optimal mode for heating convectors | |||||
| Δt= 10 °C - optimal mode for “warm floor” circuits | |||||
However, it is not always possible to rely on such tabular values, since they are usually designed for “ideal” operating conditions and do not take into account many factors. It won’t be difficult to determine the required values yourself.
- Pump performance. The main task of this device is to move a certain amount of coolant along the circuit, that is, ultimately, the required amount of thermal energy sufficient for the efficient operation of heat exchange devices (radiators, converters, “warm floor” circuits).
The calculation requires the following values:
W – the required thermal power (expressed in watts) of the heating system, providing a comfortable temperature in the premises under the most adverse weather conditions.
The owners should know the power value. If not, then it can also be calculated for each room separately, and then summed up.
How to independently calculate the required heat output of the heating system?
There is a clear and fairly accurate algorithm for such calculations. On our portal, it is implemented in a special calculator, which you will find in the article
Δ t – temperature difference in the "supply" and "return" pipes of the heating circuit at the entrance to the boiler and the exit from it. The optimal values for different types of heat exchangers are shown in the table above.
WITH– heat capacity of the coolant, expressed in W × h / (kg × °C). For water it is 1.16. If a different coolant is used, then this parameter should be indicated on its packaging. Happens. That this value is shown by the manufacturer in other units - in kJ / (kg × °C). It’s easy to translate - the correction factor is 0.28. That is, 1 kJ = 0.28 Wh.
Formula for calculating the required performance ( G) is like this:
G=W/(Δt × C)
This formula yields a performance indicator expressed in kilograms per hour. It remains only to translate this value into a volumetric expression, taking into account the density.
We suggest using the pump performance calculator - it will quickly and accurately lead to the desired result.
The circulation pump increases the efficiency of the autonomous heating system, allows 100% use of all heating circuits.
Professional installation of a heating pump guarantees high performance, reduces operating noise and reduces maintenance and repair costs. Installation of the device does not cause any particular difficulties, but there are a number of nuances that are important to consider.
We will tell you how to choose a circulation pump, help you decide on the optimal scheme for inserting equipment into the system, outline installation requirements, and also provide step-by-step instructions for installing the device.
Previously, circulation pumps were used only in centralized heating systems, and for private housing construction the natural movement of the coolant caused by temperature differences was the norm.
Now forced circulation is used everywhere thanks to the emergence of compact and inexpensive models designed to service the heating networks of small houses and cottages.
With the advent of circulation pumps, the number of circuit solutions has expanded. It became possible to lay long highways of varying complexity, while the dependence on slope practically disappeared
Due to the increase in the speed of movement of the coolant in the pipeline, thermal energy flows faster to the heating radiators, and accordingly, the rooms are warmed up faster. The load on the boiler has decreased because the water is also heated faster.
The need to install bulky and inconvenient large-diameter pipelines has disappeared; contours have become easier to camouflage under floor coverings or be buried in walls.
It has become possible to install a “warm floor” system on any floor of a private house, which operates effectively only at a certain pressure in the network
The main disadvantage of pumps for heating systems is their dependence on electricity. If the power supply is intermittent or there is a risk of a complete power outage for some period, it is necessary to install a backup power generator or at least an uninterruptible power supply.
The remaining disadvantages relate to the designs and functionality of various types of devices. For example, monoblock units and devices with a dry rotor are noisier and require constant maintenance, while a pump with a wet rotor is demanding on the quality of the coolant and has a pressure limitation.
Criteria for proper selection of equipment
All installation efforts will be reduced to zero if the equipment is selected incorrectly. In order not to make a mistake, it is necessary to first analyze all aspects of a particular heating system and make the necessary calculations.
Main types of pumps
According to their design features, all devices are divided into 2 categories: with a wet and dry rotor.
Wet pumps. This option is suitable for private homes. The unit is compact, almost silent and has a modular structure that is convenient for maintenance and repair.
But, unfortunately, it does not have high productivity - the maximum efficiency of modern models reaches 52-54%.
Circulation devices for heating networks should not be confused with similar devices for hot water supply. The heating pump does not require an anti-corrosion bronze or stainless steel housing and additional protection against scale - accordingly, it is cheaper
Dry rotor pumps productive, unpretentious to the quality of the coolant, capable of working under high pressure and do not require a strictly horizontal location on the pipe. However, they are noisier, and their operation is accompanied by vibration. Many models are installed on a foundation or metal support frame.
For installation of console, monoblock or “In-line” models it is necessary. It is advisable to use them when a flow rate of more than 100 m³/h is required, that is, for servicing groups of cottages or apartment buildings.
Brief overview of technical characteristics
When choosing a pump, you should definitely study the technical characteristics and compare them with the requirements of the heating system.
The following indicators are important:
- pressure, which covers hydraulic losses in the circuit;
- performance– volume of water or supply over a certain time interval;
- operating coolant temperature, max and min – for modern models on average +2 ºС… +110 ºС;
- power– taking into account hydraulic losses, mechanical power prevails over useful power.
Structural details are also important, for example, the inlet/outlet diameter of the pipes. For heating systems, the average parameters are 25 mm and 32 mm.
The number of electric pumps is selected, focusing on the length of the heating main. If the total length of the circuits is up to 80 m, one device is enough, if more, additional devices will be required
An example of a unit for equipping a residential heating network with an area of 100 m² is a pump Grundfos UPS with a 32 mm pipe connection, a capacity of 62 l/s and a weight of 3.65 kg. A compact and low-noise cast-iron device is not audible even behind a thin partition, and its power is enough to transport liquid to the 2nd floor.
Pumps with built-in electronics allow you to quickly switch equipment to a more convenient mode, depending on changes in temperature or pressure in the network. Automatic devices are equipped with digital displays that provide maximum information on the operation of the pump: temperature, resistance, pressure, etc.
Additional information on the calculation and selection of a circulation pump for heating is presented in the articles:
Requirements for installation of a circulation pump
There are a number of standards that regulate at the legislative level the installation of a circulation pump in a heating system. Some of the rules are set out in SNiP 2.04.05 “Heating...”. For example, it talks about priority in heating networks.
Almost all requirements are justified by the operating efficiency of the system as a whole and the circulation device in particular. For example, the shaft of a device with a wet rotor must be installed on the pipe strictly horizontally in level so that there are no air pockets inside and the pump parts do not wear out prematurely.
A mandatory element of the system is an expansion tank that compensates for changes in the volume of coolant during heating/cooling. Its place in a closed system is on the return line, in front of the circulation pump
A filter for dirt and abrasive particles is needed in any case, even when installing monolithic models. Filtered coolant will cause much less damage to pump parts than liquid with sand and suspended matter.
The mudguard is installed with the plug down in the direction of water movement to reduce resistance and facilitate system maintenance.
Some rules are dictated by manufacturers. For example, it was customary to install old models of certain brands exclusively on the return line, since they could not withstand high temperatures.
Now pumps have become more versatile and can be installed in any suitable location, but subject to power parameters.
Analysis of installation technology
The installation process itself is quick; to secure the housing, you need to secure two union nuts. This is very convenient for further maintenance and repair work. But before installation, it is necessary to choose the right installation location, otherwise the pump will either work intermittently or will soon fail.
Schemes for inserting a pump into the network
When choosing one of the schemes, it is necessary to take into account the type of heating system, boiler model and ease of maintenance.
Option 1. This is the most common solution: the pump is mounted on the “return”, through which the cooled coolant returns to the boiler. Warm water does not have such an aggressive effect on the parts of the device, so it lasts longer.
Modern devices can easily withstand high temperatures, but there are still experts who reject such a scheme.
A device such as a heating circulation pump can increase the efficiency of autonomous heating systems in country houses and country houses. Installing this pump in a heating system is not particularly difficult, so you can perform this procedure yourself, with at least minimal skills in working with technical devices, without the involvement of qualified specialists.
Purpose of circulation pumps
The main task that circulation pumps for heating boilers solve is to ensure constant movement of the liquid transmitting thermal energy through the pipeline without changing the flow pressure. Thus, constantly moving through the pipeline at a certain speed, heated water contributes to better transfer of thermal energy to the elements of the heating system and, accordingly, faster and more efficient heating of rooms.
Installing a circulation pump in a heating system operating on the principle of forced recirculation is a prerequisite. Such devices are also installed in heating systems with natural coolant circulation to increase their thermal power. Many modern models of circulation pumps can operate at different speeds and are equipped with a special switch that allows you to select the required operating mode.
Using adjustable circulation pumps, you can effectively control the operation of the heating system, turning it on to the maximum level of heat transfer when it gets very cold outside, and setting the economical operating mode after a comfortable air temperature has been established in the heated rooms. Certain models of adjustable pumps for heating boilers can operate in auto mode, responding to changes in air temperature in heated rooms and switching to the required rate of coolant supply into the pipeline system.
According to their design, circulation pumps installed on heating systems are divided into two large categories: with a “dry” and “wet” rotor. Devices with a “dry” rotor have higher efficiency and productivity, but they produce loud noise during operation and are more difficult to maintain and repair. Hydraulic machines with a “wet” rotor are characterized by ease of maintenance and high reliability and, if the required quality of the coolant is ensured, they can last more than ten years without failure.
In addition, circulation pumps of this type produce minimal noise during operation. Even the low efficiency and performance of pumping devices with a “wet” rotor is quite enough to ensure the efficient operation of the heating system of a private house or country house.
How to choose the right installation location
Before installing the circulation pump, you need to determine the most suitable location for installation. Typically, such a pump in a heating system is installed after the boiler, on a section of the pipeline located before the first branch. In this case, there is no significant difference in which of the pipelines (supply or return) of the pipeline the heating pump is installed on. To manufacture circulation pump equipment, manufacturers use materials that can withstand water temperatures in the system reaching 100–115 ° , therefore, installing such a device even on the supply line, where the coolant temperature is maximum, will not cause any harm to it. The hydraulic characteristics of the heating system and all the elements that are included in it are also not negatively affected by which of the pipeline lines the circulation pump is installed on.
How to install a heating pump? The main attention should be paid to how the piping of the pump is made and how the rotor is oriented. In heating systems consisting of two separate branches (circuits), each of which works to heat different parts of the house or its floors, it is better to install two circulation pumps - separately for each of the circuits. The scheme for installing circulation pumps on each of the branches of the heating system is left the same - immediately after the boiler and before the first branch on the pipeline.
The use of a separate pump for each of the branches of the heating system allows you to control the heat transfer of each of these heating circuits, creating the required temperature in the rooms that are served by such circuits.
If the first and second floors of the house are served by separate heating circuits, the use of two circulation pumps will also allow saving on heating the building. This saving lies in the fact that heating the upper floors, where the air temperature is always higher, requires less thermal energy from the heating system. Accordingly, the circulation pump serving the heating circuit of the upper floors can be set to a lower operating speed, which will save on energy resources used to heat water in the boiler.
Strapping schemes
The connection diagram for the boiler pump depends on the type of heating system on which such a device is installed. As mentioned above, there are heating systems with forced or natural circulation of coolant. The first ones simply do not work without such pumping equipment, the second ones work, but at the same time they are characterized by low heat transfer. As a rule, heating systems that can function both with and without a circulation pump are used to equip houses located in areas where there are frequent power outages. The use of such combined options allows you to keep warm in the house, regardless of the presence of voltage in the centralized power supply network. In cases where no electric current is supplied to the house, the heating system, although with less heat transfer, also works without a circulation pump.
Installation in heating systems with forced circulation of coolant
The installation of the pump in the heating system of a private house, which was originally designed with the use of such a device, is carried out in a break in the supply or return pipe of the circuit. A very common reason for the incorrect operation of the circulation pump and even its failure is the low quality of the coolant, the presence of sand and other insoluble impurities in its composition. In particular, this reason is typical for those cases when an open heating system is used to heat the house.
Solid insoluble particles contained in the coolant often cause the impeller to jam and subsequently stop the drive motor. In order not to encounter such problems, it is necessary to install a coarse strainer on the section of the pipeline through which the coolant enters the pump.
For the correct installation of the circulation pump in the heating system, it is necessary to install ball valves on both sides of such a device. These valves are needed in order not to drain the coolant from the entire pipeline during maintenance or repair of the pump.
Installation in heating systems with natural coolant circulation
To install a pump for a heating boiler serving a system with natural circulation of the coolant, it is imperative to use a bypass. This is a pipe jumper through which the coolant moves in the heating system in cases where the electric pump installed on it is not working.
A ball-type valve is mounted on the bypass, which is in the closed state during normal operation of the circulation pump. In cases where the hydraulic machine does not work for any reason and, accordingly, cannot provide the required circulation of the coolant, the valve on the bypass is opened, and the section of the pipe that goes to the pump is closed. Thus, the pump is cut off from the heating circuit, and the coolant begins to move through it in a natural way.
Installation features
When wondering how to properly install a pump that will ensure efficient circulation of the coolant in the heating pipes, a number of important nuances should be taken into account. The first of these nuances is that the pump rotor, when installed, must be located strictly horizontally. This requirement is explained by the fact that only with such an arrangement of the pump with a “wet” rotor, all moving elements of its internal structure will be effectively lubricated and, accordingly, will be able to avoid excessive friction and overheating.
The second point to consider when installing a recirculation pump for heating is the direction of the coolant flow in the pipeline. On the body of any circulation pump there is an arrow that indicates in which direction the coolant should move through such a device. It is not difficult to carry out installation using this hint from the manufacturers: we look in which direction the coolant flow in the pipeline is moving, pay attention to the direction of the arrow on the pump body and install it in the correct position. It should be borne in mind that incorrect actions for installing the pump on the heating circuit can lead not only to incorrect operation of such a device, but also to its rapid failure.
When choosing a circulation pump to equip your heating system, keep in mind that some models of such devices can be installed in both horizontal and vertical positions. In the latter case, the pump can lose up to 30% of the pressure that is formed in the discharge line.
Connecting the device to the power supply
When connecting the pump to the electrical network, which requires the use of three wires (phase, neutral and ground wire), it is better to use an individual line equipped with a circuit breaker.
Circulation pumps are installed in heating systems with forced or natural circulation. It is needed to increase heat transfer and to be able to regulate the temperature in the room. Installing a circulation pump is not the most difficult task; if you have a minimum of skills, you can do it yourself, with your own hands.
What is a circulation pump and why is it needed?
A circulation pump is a device that changes the speed of movement of a liquid medium without changing pressure. In heating systems it is installed for more efficient heating. In systems with forced circulation it is a mandatory element, in gravity systems it can be installed if it is necessary to increase the thermal power. Installing a circulation pump with several speeds makes it possible to change the amount of heat transferred depending on the outside temperature, thus maintaining a stable temperature in the room.
Cross-section of a circulation pump with a wet rotor
There are two types of such units - with a dry and wet rotor. Devices with a dry rotor have a high efficiency (about 80%), but are very noisy and require regular maintenance. Units with a wet rotor operate almost silently; with normal coolant quality, they can pump water without failure for more than 10 years. They have a lower efficiency (about 50%), but their characteristics are more than sufficient for heating any private home.
Where to put
It is recommended to install a circulation pump after the boiler, before the first branch, but on the supply or return pipeline it doesn’t matter. Modern units are made from materials that can withstand temperatures up to 100-115°C. There are few heating systems that work with a hotter coolant, so considerations of a more “comfortable” temperature are untenable, but if you feel safer, put it in the return line.
There is no difference in hydraulics - the boiler, and the rest of the system, it does not matter whether there is a pump in the supply or return branch. What matters is the correct installation, in the sense of tying, and the correct orientation of the rotor in space. Nothing else matters.
There is one important point regarding the installation location. If there are two separate branches in the heating system - on the right and left wings of the house or on the first and second floors - it makes sense to put a separate unit on each, and not one common one - directly after the boiler. Moreover, the same rule is preserved on these branches: immediately after the boiler, before the first branching in this heating circuit. This will make it possible to set the required thermal regime in each of the parts of the house independently of the other, and also in two-story houses to save on heating. How? Due to the fact that the second floor is usually much warmer than the first floor and much less heat is required there. If there are two pumps in the branch that goes up, the speed of movement of the coolant is set much lower, and this allows you to burn less fuel, without compromising the comfort of living.
Harness
There are two types of heating systems - forced and natural circulation. Systems with forced circulation cannot work without a pump; systems with natural circulation work, but in this mode they have lower heat transfer. However, less heat is still much better than no heat at all, so in areas where electricity is often cut off, the system is designed as hydraulic (with natural circulation), and then a pump is installed into it. This gives high heating efficiency and reliability. It is clear that the installation of a circulation pump in these systems is different.
All heating systems with heated floors are forced - without a pump, the coolant will not pass through such large circuits
forced circulation
Since a forced circulation heating system without a pump is inoperative, it is installed directly into the gap in the supply or return pipe (of your choice).
Most problems with the circulation pump arise due to the presence of mechanical impurities (sand, other abrasive particles) in the coolant. They can jam the impeller and stop the motor. Therefore, a mesh dirt filter must be placed in front of the unit.
Installing a circulation pump in a forced circulation system
It is also advisable to install ball valves on both sides. They will make it possible to replace or repair the device without draining the coolant from the system. Turn off the taps and remove the unit. Only that part of the water that was directly in this piece of the system is drained.
Natural circulation
The piping of the circulation pump in gravity systems has one significant difference - a bypass is required. This is a jumper that makes the system operational when the pump is not working. One ball shut-off valve is installed on the bypass, which is closed the entire time the pumping is running. In this mode, the system operates as forced.
When the electricity goes out or the unit fails, the valve on the jumper is opened, the valve leading to the pump is closed, and the system operates as a gravity system.
Installation features
There is one important point, without which the installation of the circulation pump will require rework: it is necessary to rotate the rotor so that it is directed horizontally. The second point is the direction of flow. There is an arrow on the body indicating which direction the coolant should flow. This is how you turn the unit so that the direction of movement of the coolant is “in the direction of the arrow”.
The pump itself can be installed both horizontally and vertically, just when selecting a model, make sure that it can work in both positions. And one more point: with a vertical arrangement, the power (pressure created) drops by about 30%. This must be taken into account when choosing a model.
Power connection
The circulation pumps operate from a 220 V network. The connection is standard; a separate power supply line with a circuit breaker is desirable. The connection requires three wires - phase, neutral and ground.
The connection to the network itself can be organized using a three-pin socket and plug. This connection method is used if the pump comes with a connected power wire. It can also be connected via a terminal block or directly with a cable to the terminals.
The terminals are located under a plastic cover. We remove it by unscrewing several bolts and find three connectors. They are usually labeled (the pictograms are N - neutral wire, L - phase, and “ground” has an international designation), so it’s hard to make a mistake.
Since the entire system depends on the performance of the circulation pump, it makes sense to make a backup power supply - install a stabilizer with connected batteries. With such a power supply system, everything will work for several days, since the pump itself and the boiler automation “pulls” electricity to a maximum of 250-300 W. But when organizing, you need to calculate everything and select the battery capacity. The disadvantage of such a system is the need to ensure that the batteries do not discharge.
The circulation pump increases the efficiency of the autonomous heating system and makes it possible to use all heating circuits 100%. Professional installation of a pump in the heating system of a private home allows you to reduce repair and maintenance costs, as well as reduce operating noise and guarantee more efficient performance.
- productivity - the volume of coolant or pumping over a certain period of time;
- pressure that covers hydraulic losses in the pipeline;
- power;
- operating coolant temperature.
- using a boiler connected to automation;
- differential circuit breaker;
- uninterruptible power supply.
- pliers;
- a set of keys;
- sealant;
- tow.
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General information
Until relatively recently, circulation pumps were used only in centralized heating schemes, and for private houses the natural movement of the coolant due to temperature differences was considered the norm. Today, forced circulation is used almost everywhere thanks to the advent of small and inexpensive devices that are designed specifically for servicing the heating system of private cottages.
By increasing the speed of movement of the coolant in the pipes, heat flows faster to the radiators, and accordingly, all rooms are heated almost instantly. The load on boiler equipment is reduced, since heating of the liquid also occurs faster.
Installation of a GRUNDFOS circulation pump in a heating system. Bypass installation
There is no longer any need to connect inconvenient and bulky large cross-section pipes. It has become easier to hide contours under the floor covering.
The main disadvantage of circulation pumps is their dependence on electricity. If the electricity supply is intermittent, then installation of a backup power source is required. The remaining disadvantages relate to the functionality and design of devices of various types. For example, monoblock and rotary pumps are noisier and require regular maintenance, while a pump with a wet type of operation is more demanding on the quality of the coolant.
Types of pumps
Based on their design features, all pumps are classified into two main groups: dry and wet rotor. For private houses, it is best to connect the pump to a wet-type heating boiler. It is small, almost silent and easy to maintain, but it does not have very high performance: efficiency is no more than 55-57%.
Devices with a dry rotor are more powerful, unpretentious to the quality of the coolant, can operate under high pressure, and are installed vertically. But they are quite noisy and vibrate a lot. Most pumps are mounted on a foundation or a support frame on the wall.
To install “In-line”, monoblock or console devices, there must be a special room - a boiler room. They are most often installed if the hot coolant circulates more than 120 m³/h, that is, these pumps are required to service multi-story buildings.
Pump. Delivery or return? Where to put it right. Answers on questions
Main characteristics
When choosing a pump, it is necessary to study the technical parameters, comparing them with the requirements of the heating system.
The main criteria are:
Structural elements are also important, for example, the diameter of the inlet and outlet pipes. For heating systems, approximate parameters will be 25−32 mm.
Devices with built-in electronics make it possible to quickly switch the system to a more convenient mode, taking into account changes in temperature or pressure in the circuit. Automatic pumps are equipped with digital screens that provide information about the operation of the device.
Installation rules
There are certain norms and rules that describe at the legislative level where and where it is correct to install the circulation pump. The main part is regulated by SNiP 2.04.05. Almost all rules are based on the operating efficiency and performance of the heating system as a whole, including the pump. For example, the shaft of wet-type equipment must be cut into the pipeline clearly horizontally so that no air pockets appear inside.
A coarse filter must be included in the heating circuit even during the installation of monolithic models. The filtered coolant will cause much less damage to all pump elements than contaminated water.
Certain rules are specified by equipment manufacturers. For example, until relatively recently, some models of the old pump group could only be installed on the return line, since these pumps could not withstand elevated temperatures. Today, pumps are universal in nature and the location of this equipment can be done at any convenient site.
The pump itself can be installed both vertically and horizontally; only when choosing a device you need to make sure that the equipment can operate in both positions. You also need to take into account one nuance: during vertical installation, the power is reduced by approximately 35%. This must be taken into account when choosing a device.
Heating diagram Connecting batteries and heating radiators Single-pipe two-pipe heating system
Mounting schemes
When choosing one of the schemes for how to properly install a pump for heating a private house, you must definitely take into account ease of maintenance, the type of boiler and the type of heating system.
The first method is the most popular: the pump is installed on the return line, through which cold coolant is supplied to the boiler. Cool liquid does not act so aggressively on all elements of the device, so the equipment can last longer.
The second method is used if, for certain reasons, it is impossible to install a pump on the return line. In this case, it is fixed at the beginning of the circuit, but not near the boiler itself, but behind the safety group.
Another option for the heating system is when an expansion tank is installed at the highest point of the circuit. If you additionally install a pump, it will be possible to operate the system in two modes - forced and natural. In this case, you can choose which method to use in each specific case.
The last scheme can only be applied to systems with a solid fuel boiler. The pump is not installed on the supply pipeline due to the possibility of explosion. It’s just that with boilers of this type it is impossible to instantly stop the fuel combustion process, as a result of which the coolant begins to boil.
Hot liquid simultaneously with steam penetrates inside the pump unit, which reduces performance. The cold coolant in the circuit does not have time to flow back into the boiler in the required volume, and the boiler begins to heat up even more. The consequence of overheating is an explosion.
If cold liquid from the circuit is supplied to a heating boiler, condensation will form. To prevent this from happening, the water is first heated in the small circuit to +50 degrees, and then the thermostatic valve smoothly transfers the liquid to the large circuit. This way, the cold coolant mixes with already heated water, and boiling does not occur.
Strapping methods
Piping is equipment that is required for the proper operation of the pump unit, as well as for the smooth functioning of the entire heating system.
First you need to finally decide how many pumps will be installed. For one circuit, one device is sufficient, but for a complex circuit it is better to install two or more.
If you plan to install a heated floor or use a boiler, then it is advisable to increase the number of units to two. If there are two boilers in the house, then separate pumping equipment will also be needed for each of them.
Ball valves are required for installation in the heating system. They are installed simultaneously with the pumping unit. A check valve is also required so that the coolant moves in one direction. The valve is installed on the pipe immediately after the pump in the direction of fluid movement.
Installing a circulation pump
It is necessary to install a coarse filter to prevent sand and dirt from entering the device body. Fine filters are not installed in the heating system. If purified water is required, it is pre-cleaned before pouring into the boiler.
There is a risk of air entering the system, so it becomes necessary to install an air valve that can turn on automatically. There are also manual options.
After installation of the equipment, an electrical connection is required. Do not connect to a regular outlet without grounding. This is a gross violation of safety regulations, which during an emergency can lead to dire consequences.
There are smarter connection options:
It is best to use a circuit breaker. To do this, you need an 8 A switch, contacts and cables. If you plan to use a UPS, you can simultaneously connect it to both the pumping equipment and the boiler.
When connecting equipment to electricity, it is necessary to exclude the possibility of condensation entering the terminal box. Heat-resistant cable is used if the thermal fluid in the heating system heats up more than 95 °C. It is prohibited for the cable to come into contact with the pump housing, electric motor, or pipe walls.
Installation instructions
Correct installation of the circulation pump in the heating system is carried out using a bypass. This is due to several reasons: this way you can quickly dismantle it or temporarily disconnect the device from the network, for example, when problems with electricity arise.
There are different models of ready-made pump units on sale - for flange mounting or welding, with areas for mounting valves or taps, with additional space intended for a pump. But if it is impossible to buy a ready-made unit or there is no place to install it, then you can make the bypass piping yourself and secure all the elements.
To work you will need:
American nuts, as a rule, are included with pumping equipment, but drives, adapters and taps must be purchased in advance. Attention should be paid to the quality of the material and the diameter of the products.
How to install the pump?
Installation steps:
The pump unit is serviced in operating mode. It is necessary to regularly clean the filter and monitor the pressure gauge readings. If the readings do not correspond to the norm, the device must be dismantled and its position adjusted.
After installation work is completed, the heating system is filled with water. Then the air is removed using the unscrewed central screw, which is located on the housing cover. The appearance of water indicates the complete removal of air pockets from the heating system. The pump can then be turned on.
As practice shows, most home craftsmen are quite capable of installing a circulation pump with their own hands. But when difficulties arise, it is better to seek help from professionals, since only experienced specialists know how to properly tie and install pumping equipment, observing all the nuances of the heating system.
