To distribute heat evenly in a house equipped with an autonomous heating system, various models of circulation pumps are used. This equipment provides forced circulation of coolant through pipes and radiators. In this case, the radiators are heated simultaneously in all rooms, regardless of their distance from the heating boiler.
The heating pump is installed in accordance with the manufacturer’s instructions, which describe in detail the installation process of this equipment. In practice, several methods of arranging pumping units in the heating system of a private house have been tested. In each case, the owner of the facility selects the most suitable option, taking into account the type of boiler and expansion tank used, the type of heating system, and the presence of additional elements.
Selecting the right unit
When choosing a circulation pump for an autonomous heating system, they are guided by two main criteria - unit performance and pressure. The first of these parameters characterizes the volume of coolant that the unit can pump over a certain period of time, and the second indicates the height to which the pump can lift the liquid. In addition, you need to consider:
- The cross-section of pipes to which the circulation pump will be connected.
- Dimensions of the space allocated for installation of the pumping unit.
- Maximum coolant temperature.
- Power and throughput of the heat generator.
- Volume of heated premises.
We have already talked about the classical calculation method in the article. At the same time, there is a simpler method that can be used both for preliminary calculations and for checking the results of more thorough calculations. It is based on the requirement that the circulation pump must pump three times its filling volume through the heating system in one hour of operation.
The last value can be indirectly estimated from the power characteristics of the boiler. If the thermal unit was selected according to the rules, then for every kilowatt taken from its technical data sheet there are at least 15 liters of coolant. It is enough to multiply the power of the heat generator in kW by 15 and make a correction of 20% in order to estimate the filling of the heating circuits with sufficient accuracy. After the volume of coolant has been calculated, it will not be difficult to calculate the required performance of the circulation pump in l/min - to do this, the filling of the circuits in liters must be multiplied by three and divided by sixty. If we take a heating system with a 15 kW boiler as an example, we can assume that the volume of liquid in all its branches is approximately 270 liters (Q = 15 kW x 15 l + 20%). For forced circulation of coolant, you will need a pump with a flow rate of at least 0.81 m 3 /hour or 13.5 l/min.
The required pressure value of the circulation pump can also be determined without going into complex mathematical calculations. To do this, you can use the formula N = X * K, where X is the number of floors of the building, including the basement, and K is a correction factor equal to 0.7-1.1 for traditional two-pipe heating schemes and 1.2-1.85 for collector-radial circuits. So, if you calculate the hydraulic resistance of a collector heating system of a two-story building with a basement (the number of levels is three), then you will need a pump with a pressure of 3x1.85 = 5.55 m.
The obtained values will already be enough to decide on a specific model of a circulation pump from any manufacturer. To do this, the operating point is found on the graphs of the hydraulic characteristics of centrifugal units - it is located at the intersection of the segments drawn from the abscissa (performance) and ordinate (pressure) axis. The best position of the operating point is considered to be the middle third of the graph, which corresponds to the maximum efficiency.
The graph of the hydraulic characteristics of the circulation pump allows you to analyze whether the unit meets the requirements for pressure and performance
To obtain a sufficient reserve in both directions, you should focus on the curve constructed for the average speed of the circulation pump. In this case, it will be possible to reduce its power if there is excessive noise or increase it if the coolant at the entrance to the boiler has an unacceptably low temperature.
Features of the design of a heating system with pump circulation are studied in this article:
Thermal valves installed in many heating systems regulate the room temperature in accordance with the specified parameters. The valve closes when the temperature rises. This increases hydraulic resistance and, accordingly, increases pressure. These processes are accompanied by the appearance of noise, which can be eliminated by switching the pump to low speed. Pumps with built-in electronics that can smoothly regulate pressure drops depending on changes in the amount of water cope with this task more effectively.
Determining where the pump is inserted into the system
When installing a circulation pump, it is necessary to take into account not only the manufacturers' recommendations, but also the possibility of its periodic maintenance. More recently, it was recommended to install pumps with a “wet” rotor exclusively on the return line - it was believed that this way they would work much longer, since they would be in a more gentle temperature regime.
Typical diagram for connecting a pump providing forced circulation of coolant to an autonomous heating system of a private house or country cottage
Modern units are designed for long-term contact with hot liquid, so they can be safely installed on the supply side. Moreover, experts often recommend installing the pump on the supply pipeline in order to increase the pressure in the suction zone. In this case, the specified area will have the highest temperature, so you must ensure that the electrical device is capable of contact with high-temperature liquid. The advantages of this method can be appreciated, for example, by owners of warm water floors, since in this case the formation of air pockets is eliminated.
For heating systems with membrane tanks, on the contrary, it is recommended to install a bypass with a pump on the return side, closer to the expansion tank. If such a scheme makes it difficult to service the pump, then it is cut directly into the main line, always equipping the circuit with a check valve.
Choosing a circulation pump and deciding where to install it is only half the battle. It is equally important to carry out the piping correctly - only in this case can you count on long, trouble-free operation and the possibility of comfortable servicing of the unit. There is nothing complicated in the recommendations of experts:
- The pump installation location should be equipped with ball valves. With their help, it will be possible to isolate the unit from the coolant during preventive or repair measures.
- On the coolant inlet side, it is necessary to install a coarse filter, which will serve as a barrier to mechanical particles. As practice shows, the presence of such a device slows down the process of abrasive wear of the impeller several times. If we talk about the danger of damage to the pump, then the importance of filtration is difficult to overestimate.
- The uppermost point of the bypass should be equipped with a venting valve.
- The direction of movement of the coolant must coincide with the arrow on the device body.
- Since in “wet” type pumps cooling and lubrication is performed by the pumped coolant, the axis of rotation must be parallel to the horizontal.
- To ensure tightness, mating parts and their joints are sealed using gaskets and sealants.
It is equally important to correctly connect the pump to the electrical network. The type and cross-section of the cable must correspond to the power of the unit, and the connection must be made only with protective grounding.
Basic installation rules
Any equipment is supplied accompanied by the manufacturer’s instructions, which reflect all the important information about its design, operating principle and installation rules. After reading this technical document carefully, you can understand the basic rules for handling it.
When installing it yourself, it is very important to choose the desired position of the product relative to the horizon. The location of the electric motor shaft must be strictly horizontal. Otherwise, air pockets may form, which will leave the bearings without lubrication and sufficient cooling. This will lead to rapid wear of parts and rapid equipment breakdown. There is an arrow on the pump body in the direction in which the coolant in the system should move.
Options for correct and incorrect placement of a circulation pump with a “wet” rotor. It is strictly prohibited to place equipment as shown in the bottom row.
The need for water filtration
A sump tank is installed in front of the pump, the function of which is to filter the coolant. The mud filter traps abrasive particles, sand, scale and other contaminants that get into the water. If such elements get inside the pump, the impeller and bearings may be destroyed. Since the diameter of the insert for mounting the pump is small, you can use an ordinary coarse filter. Please note that the barrel, which serves to collect various suspensions, is directed downward. Being in this position, the filter will not serve as an obstacle to water circulation. When partially filled, the barrel will not lose its ability to pass coolant.
Important! Most filters are equipped with an arrow indicating the correct direction of water flow in the circuit. If you ignore the direction of the arrow, you will have to clean the mud pan much more often.
Pump location in the heating circuit
In principle, most models of modern pumps can work equally well on both supply and return. The equipment can be installed in any part of the heating circuit. It should be taken into account that the duration of operation of the bearings and plastic parts of the device will depend on the temperature of the coolant. Therefore, it is better to install the equipment on the return pipeline after the expansion membrane tank and before the heating boiler.
One of the options for correctly inserting a circulation pump into the pipeline of the heating system of a private house with a circuit length of no more than 80 meters
Why is bypass needed?
The circulation pump is a volatile device. When there is a power outage, the heating system must operate under natural circulation conditions. To do this, it is necessary to minimize resistance in the circuit by reducing the number of bends and turns, as well as using modern ball valves as shut-off valves. When open, the clearance in the ball valve coincides with the diameter of the pipe.
The circulation pump is installed on, which is cut off from the main system using two ball valves. This placement of the equipment allows it to be repaired or replaced without damaging the heating system of the house. In the off-season, the heating system can operate without a pump, which is shut off using the same ball valves. When frost intensifies, the pump is put into operation by opening the shut-off valves along its edges and closing the ball valve on the main circuit. This is how the direction of coolant flow is adjusted.
Installation of the circulation pump on the bypass (bypass pipe) using three ball valves ensures the coolant flow in the desired direction
Electrical connection
If the heating system is designed on the principle of forced circulation, then in the event of a power outage the pump must continue to operate from a backup power source. Therefore, it is recommended to install an uninterruptible power supply that will allow the heating system to function for a couple of hours. This time is usually enough for specialists to eliminate the cause of an emergency power outage. External batteries connected to a backup power source can extend the battery life of the equipment.
Connecting the pump to an uninterruptible power supply (UPS), which is additionally reinforced by three battery units connected in series into a single circuit
When making electrical connections to the equipment, it is necessary to eliminate the possibility of moisture and condensation getting into the terminal box. A heat-resistant cable is used if the coolant heats up in the heating system by more than 90° C. Contact of the power cable with the walls of pipes, the engine, or the pump housing is not allowed. The power cable is connected to the terminal box from the left or right side, and the plug is rearranged. When the terminal box is located on the side, the cable is inserted only from the bottom. And yes, grounding is required!
The following material will help answer the question of why install a circulation pump:
Checking operation and putting it into operation
After completion of installation work, the heating system is filled with water. The air is then removed by opening the central screw located on the pump housing cover. The appearance of water will indicate the complete removal of air bubbles from the device. After this, the pump can be put into operation.
After reading the instructions and reading this article, you can carry out the installation work yourself. If you do not understand how to install a heating pump, then invite a professional technician.
The question of why a circulation pump is needed in the heating system of a private home does not come up so often today. Consumers have long realized that this small device solves many problems associated with the efficient operation of the heating system as a whole.
Firstly, with its help the efficiency increases. Secondly, there is an opportunity to save on materials and heating elements. More on all this below.
Features of forced circulation
A circulation pump installed in the system creates a slight pressure inside. In this case, the coolant moves at a low speed, evenly distributing heat across all radiators.
Is it really impossible for the natural circulation of the coolant to distribute thermal energy evenly?
Maybe, but due to the fact that private country houses under construction are becoming larger in size, and accordingly, the layout of pipe lines is becoming more and more complex, it is increasingly difficult for the coolant to overcome the configurations of the pipe circuits. And in such houses you simply cannot do without a circulation pump.
Advantages
Under the action of the pump, the coolant passes faster through the entire circuit of the heating system, returning to the heating boiler. However, its temperature will not be low. This means that it will be easier to heat a coolant that is not very cool. Less fuel consumption costs.
For the natural circulation of the coolant, a large volume is required so that the bulk of it can maintain the required temperature. Accordingly, for normal operation of the heating system in a private house, you will need pipes with a large diameter, radiators with wide cavities, and shut-off valves to match the pipes.
For the system in which the pump is installed, there is no need to hold a large volume of coolant. Therefore, you can safely use pipes and valves with a smaller diameter. And this means a reduction in prices for all products and savings on materials.
Flaws
In principle, such heating has only one drawback - it is energy dependent. The device runs on electric current. Firstly, these are, albeit small, costs. Secondly, when the power supply is turned off, the pumping unit stops working.
Of course, the craftsmen, taking this situation into account, install a bypass through which the heating begins to work on the principle of natural circulation of hot water. And this is a decrease in operating efficiency, plus a decrease in efficiency.
Selection of device
The crucial point is to correctly calculate the power of the installed pump. Two indicators are taken into account here:
- volume of distilled water mass, m³/h;
- pressure measured in meters.
It is very difficult to make the correct calculation if you are not a specialist in this matter. Here we have to take into account the complexity of the pipe line layout, the number of radiators and shut-off valves, the power of the heating boiler, the materials from which the pipes and other heating devices are made. Therefore, this stage is best left to a professional.
If you nevertheless decide to take responsibility, then it is best to purchase a pump in which you can switch the speed of movement of the coolant.
The ideal option is with automatic adjustment. Such a device costs several times more than a conventional model, but you have peace of mind that you can adjust it yourself to the necessary parameters of the heating system at home.
Calculation example
Before choosing a pump, the following calculation must be performed. For example, a heating boiler is installed in the basement. Your house is a two-story building. The heating system is a single-pipe installation.
That is, it turns out that the highest point of the heating system is the upper edges of the radiators installed on the second floor. This is despite the fact that the house has a closed heating system.
Head calculation
From the return pipe that enters the boiler (this is the area where the device is installed), it is necessary to measure the distance to the upper edge of the second floor radiator. This will be the pressure of the pumping device. Essentially it will look like this:
- 2.5 m – basement height;
- 3 m – height of the first floor;
- two floors – 0.5 m;
- the distance from the floor to the top edge of the radiator is 0.6 m.
The sum is 6.6 m. This means you will need a pump with a head of 7 m.
To do this, you need to know the heated area of a private house. For example, let it be 200 m². To keep a private house warm, you must adhere to the ratio: 1 kW of thermal energy per 10 m². That is, you will need 20 kW.
The next indicator is the temperature difference between the supply and return circuits. Experts recommend within 10 °C. That is, if at the outlet of the boiler the coolant temperature is +70 °C, then at the entrance it is +60 °C. Now carry out this mathematical operation: 20:10 = 2. This is the pump power, measured in m³/h.
As you can see, choosing a pump is not so difficult. Of course, this is a simple calculation without taking into account various nuances. But you can take it as a basis, adding 20% just in case.
Installation
It’s better not to do it yourself if you don’t know all the nuances of the installation process. But you need to familiarize yourself with the technology and the sequence.
Installation location
The pump is installed on the return line next to the heating boiler. This is done with one single purpose - to reduce the temperature load on the seals, cuffs and gaskets that are used in the design of the unit itself. When exposed to high temperatures, they quickly fail.
There are two types of devices: with a wet rotor and a dry one. Usually the first option is low-power pumps used for heating small private houses. It is cut directly into the pipeline, connecting on both sides with threads. The second is a more powerful installation. Such pumps are most often connected using flanges.
Shut-off valves and filter
The pump is isolated from the pipe by two valves (ball valves), which are closed if repairs are necessary.
A bypass must be installed. This is a pipe that connects the pipeline, bypassing the pumping unit. A valve must be installed on the bypass. It blocks the flow of coolant when the pump is running. And it opens when the device stops working or is in the process of being repaired. That is, the bypass works in emergency cases so that heating does not stop if the pump itself stops.
Today, a coarse filter is often installed in front of the pump. He is responsible for the quality of the coolant.
Popular manufacturers
The question of how to choose affects not only the technical characteristics of the device. Most often, consumers understand this as a brand or manufacturer. The modern market offers a fairly wide range. There are both foreign and domestic analogues here. Here are just a few models.
Italian pump Aquario
Its model AC204-130 is one of the most popular. Used for small private houses. Its power is 2.4 m³/h, pressure up to 3 m, power consumption 0.64 kW, weight 3.4 kg.
The connection is flanged and has three speed modes.
Italian DAB device VA-VB-VD
It has a wide range of technical characteristics: pressure up to 6 m with power from 0.5 to 3.3 m³/h.
This sample is equipped with a special thermal relay that turns off the pump if it starts to overheat. Many experts advise choosing this particular model.
The Danish company Grundfos offers pumps in five modifications. In Russia, the UPS model has gained great popularity as the most economical in terms of electricity consumption (0.55 kW).
At the same time, its head is 3 m, and the volume of pumped coolant is 3 m³/h.
Russian models
Among domestic manufacturers, it is necessary to highlight the “Khozyain” brand pumps from Podolsk and “Tsirkul” from the company “Dzhileks”. Several technical characteristics:
- Owner 4.25.180 – head 4.2 m, power 3 m³/h;
- Owner 8.32.180 – head 8 m, power 9.6 m³/h;
- Compass 25/40 (pressure 4 m, volume 2.5 m³/h) - the smallest sample;
- Compass 32/80 (pressure 8 m, volume 3.2 m³/h) is the largest.
Both brands produce pumps that are connected to the pipeline with a flange connection.
So, knowing the brands and models offered by manufacturers, you can choose the right pump, taking into account not only its technical characteristics, but also the price.
The operating principle of a gravity heating system with natural circulation of coolant is ensured by the temperature difference at the outlet of the boiler and at its inlet. This time-tested and practice-tested scheme not only worked for many decades, but is still used today for heating small objects.
However, they have already lost the palm to systems with forced coolant movement. This is a more profitable and practical option for organizing heating of two or more storey buildings and large premises. The movement of the coolant in such a system is ensured by a special device - a circulation pump.
Functional details of the pump
Life is more fun in motion! This is in people... And in heating, a higher speed of movement of the coolant along the circuit allows you to get a number of advantages. Naturally, shortcomings found their place here too. Let's figure it out...
Gravity heating circuits of private houses suffer from such a “disease” - uneven heating of various rooms of the house. It is hottest in the rooms that are located closer to the beginning of the coolant movement along the circuit, that is, near the boiler. And distant rooms simply do not warm up, since the coolant, due to the low speed of movement, gave up the “lion’s” part of its heat at the beginning of its journey.
The creation of forced movement of the coolant by a circulation pump contributes to more uniform heating of radiators in all rooms, due to the higher speed of fluid movement.
Features of equipment selection
Choosing the right circulation pump will allow you to find the optimal balance between efficiently functioning heating and unnecessary energy costs with an increased sound level of the pump. We explain: a very powerful pump will “eat up” a lot of “kilowatt-hours” (and it actually works around the clock), and a low power will not “push” the coolant through the entire system circuit.
To learn how to choose the right unit and have an idea of its structure, read the article. And here we will figure out the correct ways to “integrate this device into the heating circuit.
Let us only dwell on the fact that for household systems, “wet” type pumps are predominantly used - they are actually immersed in the coolant (water) that they pump. Due to this, they work very quietly, unlike their “dry” counterparts, which, due to their noisy behavior, are more suitable for industrial facilities, boiler rooms of office buildings, etc.
Contact with water causes corrosion, so the parts of such equipment are made of stainless steel, and the housings are made of bronze or brass.
Choosing an installation location
When choosing a “place of residence” for the circulating “engine” of water in the system, it is advisable (for your peace of mind) to take into account the following points:
- If the pump is installed in an old system, it must be flushed.
- The installation location must be accessible - you may need to have access to the pump in the future for maintenance or replacement.
- Mostly they are placed on the return main pipe near the expansion tank. There the coolant temperature is lower, which is safer for the device.
- Modern circulation units for heating systems can withstand high temperatures. Therefore, they can also be installed on the supply pipe of the system. The main thing is to make sure, according to the technical documentation for the device, that it is capable of operating at high temperatures. It is advisable to do this when using devices with a built-in speed control function and when using “night mode”.
- Note! The “wet type” pump can be installed in any way in terms of the direction of the pipeline. But! Its shaft MUST be positioned HORIZONTALLY! And its position should exclude the possibility of water getting into the terminal box.
- Before starting the heating system for the first time after the summer period, it is necessary to check the functionality of the device itself - the engine rotor could be blocked by deposits from the coolant.
Installation diagrams
Installation of a circulation unit in a system that was originally planned or already functioned as gravity (with natural circulation) is carried out according to the diagram below. Such systems are usually single-pipe and some uneven heating may still be observed in different rooms. With this connection, the coolant flow is constant.
When installing a two-pipe heating system, the pump is installed in a similar way, only some changes are observed in the “behavior” of the system. Thus, the use of thermostats on radiators can lead to changes in coolant flow. Such systems are characterized by a higher temperature difference.
The scheme includes:
- Boiler;
- automatic air valve;
- thermostat on the radiator;
- Radiator;
- balancing valve;
- expansion tank of membrane type;
- ball valve;
- coarse mesh filter;
- circulation pump;
- thermometer, pressure gauge or thermomanometer;
- safety valve.
Correct installation
To connect the circulation blower to a finished heating system with natural coolant flow, a kind of “transport interchange” is organized: the main pipe and a “detour” through the pump line.
To do this, a check valve (automatic version) or a ball valve of the appropriate size is installed in the section of the main pipe.
Two ball valves are installed on the surges welded into the main pipe on both sides of the valve, to which the pump itself is connected through additional pipes and fittings. The valves are designed to shut off the movement of the coolant when servicing or dismantling the pump.
Important point! Before the filter, it is imperative to install a filter for mechanical water purification, since even small particles in the water of the system, if there are enough of them, can damage the pump.
The operation of the unit is checked after it is connected, the entire system is filled with coolant and air pockets are removed from it. Air is released from the blower housing through the central screw located on its cover. Complete removal of air will be confirmed by the appearance of water. Low noise operation and evenly heated all batteries will be evidence of the correct choice of unit parameters.
Ensuring uninterrupted operation
The circulation pump is powered from an alternating electric current network (~220V). And this “trait” jeopardizes the functioning of the system in the event of a loss of power supply to the facility. Where to look for a way out and which one?
A saving option may be a circuit using an uninterruptible power supply. It must have a battery capacity reserve to support the operation of the pump (and gas boiler, if necessary) for up to 12 hours in the absence of external power supply, and at the same time produce “alternating” current without distorting its “sine wave”.
UPS, regarding their functionality, can be divided into:
- devices that allow network current (if any) to pass through itself as a “transit” without changing its parameters. If the external power disappears or its parameters do not correspond to the nominal values, the device automatically switches to “offline” mode and switches on the battery;
- devices with a linear-interactive “character of behavior” - they allow you to adjust the parameters (mostly stepwise) of the electric current passing through it from the external network within ±20% of the nominal value;
- units that provide constant power to equipment from a battery(s), which is periodically recharged from an external network. Such devices are capable of operating with input electric current with a wide range of parameters, providing a stable output voltage for consumers. This is the best option for heating equipment equipped with electronics that are sensitive to poor-quality “power,” but it is not cheap to maintain.
The power supply circuit may also include gasoline (diesel) autonomous generators, but in order to “calm the conscience”, eliminate voltage surges and guarantee reliable operation of the electronics, all equipment connections must be made through a reliable stabilizer or UPS.
Results
The advisability of installing a circulation pump in the heating system is no longer in doubt. Another thing is that the installation of the device into the system must be done correctly and reliably. The practice of operating the unit in the system in the first days should confirm the effectiveness of its operation by quickly warming up the radiators of all heated rooms.
When resolving issues with organizing the heating of their own homes, the vast majority of homeowners give preference to a water heating system. Methods for obtaining heat may vary - depending on the availability of energy sources, the types of fuel prevailing in the region, and the cost-effectiveness of one or another approach. That is, in fact, the boiler can be installed depending on the circumstances, gas, electric, solid fuel - long-burning or with automatic fuel supply, diesel, etc. But the distribution of thermal energy among rooms in in most cases it is carried out through circulating through pipe circuits - water or specially selected technical fluid.
When designing a water heating system, independently or with the involvement of specialists, it is necessary to competently approach the selection of all units, components and components, from the boiler and radiators to pipes and the last valve - everything must fully comply with the planned parameters of the system being created. The merman also plays one of the key roles heating pump, since the system equipped with a forced circulation device, it always features stable operation and high efficiency. Therefore, this publication will be entirely devoted to the nuances of pump design, criteria for their selection and basic installation rules.
Is a water circulation pump really necessary for heating?
Surely, many of the thrifty owners will wonder whether it is possible not to “bother” with the pump at all. Indeed, in a small house with slightly branched contours, it can be organized according to a natural circulation scheme.
Yes, of course, there is such a possibility. To do this, it is necessary to correctly position the expansion tank, select pipes of the appropriate diameter and mount them with a certain slope, and optimally position the heating radiators. In a word, when they talk about the simplicity of a system with natural circulation, this statement is very doubtful.
The main advantage of natural circulation - not attachment it to the electrical supply (if, of course, the boiler itself is non-volatile). In all other respects, it is significantly inferior to forced circulation.
Thermal calculations show that even with the most optimal conditions - high boiler efficiency, rational placement of all components, clean pipes not overgrown with sediment and a minimum of shut-off or other fittings, the natural increase in pressure due to the temperature difference and the creation of a slope will be within 0.6 atmospheres. This is clearly not enough to overcome strong hydraulic resistance in an extensive network or even in the event of force majeure circumstances - what happened with a narrowing of the internal clearance or even a short-term stop of the gas boiler can lead to imbalance heating system, and it will take a long time to “bring it back to life.”
So, let’s summarize the advantages and disadvantages of natural and forced circulation:
1. The advantages of natural circulation, as already mentioned, include complete energy independence and the relative simplicity of piping the boiler itself. But there is a whole list of shortcomings:
— The need to use pipes of different, including fairly large diameters, which leads to increased costs of the project and difficulties in installation. The system requires very careful thermal calculations, with precise observance of slopes, with mandatory consideration of the excess of the location of some elements over others and with other nuances.
— Transfer of thermal energy over significant distances (heights) is simply impossible. Both the height and length of the created outline are limited.
— The low speed of natural movement of the coolant leads to completely unnecessary energy losses, uneven heat distribution throughout the rooms, and therefore to a decrease in the overall efficiency of the system and its efficiency.
— A system with natural circulation is very difficult to make any precise adjustments, optimization of heat flow distributionby areas of the house.
2. And now - about forced circulation in heating circuits.
Its disadvantages include dependence on availability - if there is a power failure, the heating system stops.
- Well, firstly, nothing prevents you from organizing the entire system in such a way that it can operate in both modes - it is enough to install the pump unit on the “return” in front of the entrance to the boiler. For example, the figure reproduces the same diagram, but indicating the insertion location of the circulation pump. The strapping procedure will be described below.
“Secondly, let’s agree that now is not the “dawn of the country’s electrification.” And, hand on heart, let’s give ourselves an honest answer to the question - how often, how regularly and for what duration is electricity cut off in a particular area (city, village). If these are just annoying episodes associated with some emergency situations, then everything can be solved by installing an uninterruptible power supply system. The power consumption of circulation pumps is usually very small, and even a small UPS will easily keep the entire heating system in working order.
If, of course, there are still places where power outages are systematic and long-lasting, then in these populated areas it is certainly better to organize heating according to a natural circulation scheme.
A circulation pump is a device that allows you to intensify the process of coolant circulation through heating appliances. Installing a circulation pump often solves problems in existing heating systems that are insufficiently efficient.
Purpose
Recently, the use of circulation pumps has become very popular for heating systems. Circulation pumps are used in home heating systems for forced circulation of coolant, and they are also used to create warm water floors.
Types of circulation pumps. Choice
Circulation pumps are available with dry and wet rotor. Pumps of the first type are used mostly in stationary high-power boiler houses. Glandless rotor pumps - the rotor of an electric motor rotates in water. They have a number of advantages: quiet operation, lower energy consumption, and do not require maintenance. Such advantages of these pumps have made it possible to successfully use them in heating systems of individual houses.
The main parameters of circulation pumps with a wet rotor are their flow (the amount of water pumped per hour), pressure (how high the pump can lift water) and connecting dimensions in millimeters. Selecting a circulation pump comes down to determining the required flow in cubic meters per hour. But not only. The issue can be resolved by calculations, however, for most cases of individual houses and cottages, 25/60 or 32/60 pumps can be recommended. This is true, since most home heating systems are made from polypropylene pipes with a diameter of 25 or 32 mm. And it has been experimentally established that, according to the flow-pressure characteristics of the pumps, a pressure of 60 m of water. Art. (meters of water column) is more than enough both to completely fill the system and to create the required supply (circulation intensity).
Pump installation. How to avoid mistakes
Installation of a circulation pump consists of installing it in a certain place on the heating system pipeline. There are options here. Let's look at the installation of a pump using the example of its installation on polypropylene pipes. This method differs from installation on steel pipes only in the installation work (tapping, threading), the assembly assembly diagram remains the same.
Required materials and tools:
- polypropylene pipes of the appropriate diameter;
- necessary fittings (couplings, adapters, angles, tees);
- shut-off valves (taps);
- the pump itself;
- set of welding equipment for polypropylene pipes;
- flax or FUM tape (for sealing threaded connections);
- pipe wrench, adjustable wrench, plumbing pliers.
The pump must be installed using a bypass. This means that the main thread of the heating system pipeline is preserved, and the pump runs parallel to it. This line is assembled first. It is necessary to take a special polypropylene fitting for the transition from a metal pump to a polypropylene pipe: a combined coupling, with an external thread corresponding to the connecting dimensions of the pump. It should be installed on the pump using flax or FUM tape. This should be done on each side of the pump.
Now we weld a tap (polypropylene ball valve) to both existing couplings. The size of the tap must match the size of the coupling. Typically this knot is performed using a 90 degree angle. The angle can be set both between the coupling and the tap, and after the tap. Having done this work on both sides of the pump, we get that very parallel line - the bypass. By measuring the distance between the two extreme points of the structure, which includes a pump, couplings, two taps and two corners, we obtain the overall size of the bypass with the pump.
1 - polypropylene corner; 2 - ball valve; 3 - circulation pump; 4 — coarse filter; 5 - ball valve; 6 - polypropylene tee
Next you need to decide where to install the pump. In front of the boiler in the direction of the coolant flow, or after. The most correct installation would be in front of the boiler, on the return pipeline of the system. Installing a pump after the boiler, on the supply pipeline, is possible, but less effective, and is used only when it is not possible to install a circulation pump on the return pipeline.
Knowing the overall size of the bypass, it is necessary to mark the places where polypropylene tees are inserted into the pipeline. We cut out a section of the return pipeline according to the marks, and weld tees onto the ends of the heating system pipes (their size should match the size of the return pipeline, and the branch of the tees should match the dimensions of the pipe and bypass fitting). A tap is installed between the tees, which should not narrow the dimensions of the pipeline. Now we weld a bypass onto the branches of the tees. The dimensions of the pipe sections between the main elements of the assembly are selected from local conditions, taking into account aesthetics and ease of execution.
When installing the pump, you should pay attention to the fact that the axis of the pump electric motor is positioned strictly horizontally; possible options are always well described in the documentation for the pump.
You should wind flax or FUM tape onto the thread clockwise, looking at the cut of the thread. For better compaction, it is recommended to first wind a little flax, and then 5-6 turns of FUM tape.
It is important to think about how the entire assembly with the pump will look in order to take into account various possibilities and not make a mistake.
When working with polypropylene pipes, it is necessary to provide for the need to mount the pump to a wall or floor. Most often, metal clamps with a hairpin are used for this.
Connecting the pump to the electrical network is not difficult. For some manufacturers, this requires simply inserting a standard electrical plug into an outlet. But more often, you need to make a cord with a plug yourself (we buy a piece of an electric three-core cord and a plug). Having opened the pump cover (screw for a Phillips screwdriver), insert the cord inside and connect it to terminals N, L, and ground. Do not confuse the “zero” and “ground” contacts!
Before starting the pump for the first time, it is necessary to bleed the air from the pump after filling the system with water. To do this, you need to slightly unscrew the plug on its body until water appears, and then tighten it tightly.
