How is the heating pump installed? Where to install the circulation pump: modernizing the heating system

The most common problem that owners of country houses have to face during the cold season is uneven heat distribution in the heating system. The natural circulation of hot water in the circuit is often not enough: the liquid in the boiler reaches the boiling point, and the radiators in distant rooms remain barely warm. Upgrading an existing system is not so difficult - you just need to arrange forced water exchange using special equipment. But where to install the circulation pump so that it works as efficiently as possible?

Correct and incorrect installation of the circulation pump

Circulation pump functions

Let's start with the fact that there are two ways to improve the heating situation in a private home - by installing larger diameter pipes or by installing a pump. The first option is used extremely rarely, since it involves a complete rework of the system. It can only be considered when building a new house, and even then there are few people willing to spend money on an expensive network. It is much easier and cheaper to equip a new or existing system with a circulation pump.

What does the unit insertion give:

The inertia of the system is reduced, as a result of which the house warms up much faster.
The temperature of pipes and radiators located at different distances from the boiler is equalized.
The influence of the counterslope is leveled out, and the problem of air jams will disappear.

Important! You should not design a heating system designed only for forced circulation. A prolonged power outage will cause the coolant to overheat.

Circulation pump connection diagram

Pump location in the circuit

Where should I install the circulation pump? Formally, modern equipment works equally well on any part of the circuit - both supply and return. However, it is better to take into account certain nuances:

High temperature reduces the life of bearings and plastic elements of the device, so it is better to embed it on the return pipe (in front of the boiler).
The expansion tank must be mounted on a pipe section with a uniform water flow, and the pump will inevitably add turbulence. For this reason, the equipment is recommended to be placed in front of the boiler, but after the expander.

Important! Before installing a circulation pump, make sure that it is capable of handling boiling water.

To facilitate installation, it is better to purchase a device with a detachable thread. Otherwise, you will have to select adapters.

Among other things, you will need a deep filter, a check valve, valves, a bypass, a set of wrenches and a factory installation manual for the pump.

What is a bypass for?

Where to install the circulation pump so that it does not interfere with natural water exchange? The gravitational heating system is characterized by minimal differences between the supply and return pipelines, and for optimal speed, minimal hydraulic resistance is required. Any turns and bends of the circuit, stop valves and a decrease in the pipe clearance can worsen the situation.

Important! For an autonomous heating system, only modern ball valves are suitable that fully open the clearance in working order.

You can purchase a ready-made bypass in the store

A bypass - a piece of pipe installed between the direct and return wiring - serves precisely to reduce the negative impact of the circulation pump on the hydraulic resistance. The equipment is embedded according to the following scheme:

The pump is installed parallel to the main circuit, and the diameter of the bypass pipe must be less than the diameter of the main pipe.
A valve is installed between the taps, which should close the main circuit. Otherwise, the equipment will distill water between taps without directing it into the system.
Safety valves are installed on both sides of the device. They allow you to cut off a non-working device and dismantle it if necessary.
A check ball valve must be installed on the bypass - in the event of a power outage, it will switch the system to natural circulation.

Important! If natural circulation is not provided, it is necessary to install a circulation pump with an uninterruptible power supply. These can be external batteries powered from a backup source.

Installing a pump in an old heating system

An old heating system with natural circulation sooner or later begins to “sabotage” its duties. Rust, scale and sludge appear in the pipes, which reduce their clearance and prevent hot water from moving along a given contour. Before installing the circulation pump, it is necessary to carry out resuscitation measures:

Replace the old expansion tank with a membrane model. This way you will prevent further corrosion and can reduce heat loss.
The closed expansion tank must be equipped with a safety valve that will relieve emergency pressure if the system overheats.
Thoroughly flush the entire pipeline by connecting it through hoses to the water supply. Take the time and effort to remove as much rust and sludge as possible.

Professional flushing of the heating system

Important! If your heating system runs on a solid fuel boiler, it is better to install the circulation pump on the return line so that it does not overheat from too high a temperature.

To check the correct installation of the equipment and evaluate its performance, the system is filled with water. The central screw on the device body is opened to remove air pockets. As soon as water appears, the pump can be started.

You can carry out installation work yourself if you have sufficient knowledge and are confident that you can apply the correct installation scheme. If you have any doubts, contact a specialist. It is better to spend a small amount of money on calling an installer than to eliminate the consequences of amateur performance in severe frosts.

Video: installing a circulation pump

For efficient heating of private houses, the heating system requires a circulation pump. Thanks to this device, continuous circulation of coolant through the pipes is carried out. The room warms up evenly and quickly. At high or low speed of coolant movement, the house is heated unevenly. Therefore, you should carefully approach such an issue as selecting a circulation pump for a heating system.

The selection of a circulation pump for heating does not depend on what fuel is needed for the heating boiler.

1 Why do you need a pump in the heating circuit?

The natural circulation of liquid in the heating circuit is ineffective, since the liquid constantly overcomes resistance, and this slows down its progress. This leads to the fact that the liquid is returned to the boiler cooled, and this requires additional costs for its additional heating.

Using narrower pipes only partially solves the problem, but the cost of reconstruction is much higher than for a circulation pump.

Forced circulation forces the liquid to move faster along the system circuit and return to the boiler not very cool. Fuel consumption costs are therefore reduced.

In systems without a pump, a large volume of coolant is required to maintain the required temperature. To do this, you will need large-diameter pipes and radiators with wide blades.

In forced circulation, a large volume of liquid is not needed. Therefore, pipes with a smaller diameter are suitable. And this saves on materials.

The disadvantage of this type of heating is its energy dependence. The device runs on electric current.

1.1 Design

Most devices are of this design:

the body to which the volute is attached;
the system pipes are connected to the volute;
the housing contains an electric motor with terminals and a control board;
a rotor with an impeller, thanks to which water moves.

When the pump operates, a vacuum is obtained at the inlet of the device and the required pressure at the outlet.

2 Types of devices

There is a fairly large selection of circulation pumps on the market. How to choose a heating pump? The most common circulation pumps are devices with a wet and dry rotor.

2.1 Wet rotor mechanism

In a device with a wet rotor, the impeller and rotor are located in the coolant. This helps cool the pump motor, and the device is thus protected from overheating. These parts are made of materials that are non-corrosive.

The disadvantage of devices of this type is that they have low efficiency. Advantages of this type:

low noise level;
availability;
does not require regular maintenance.

Devices with a wet rotor are used for heating in small houses. The low power of the pump allows you to choose a circulation pump for heating of this type in cases where the volume of liquid in the system is small.

2.2 Device with dry rotor

The impeller in a device of this type is located in the coolant, and the rotor is protected from liquid by sealed gaskets.

Selecting a pump for a heating system of this type will show the advantage of high pump power. Due to this, it is used in rooms with a large area. The device has a fairly high efficiency.

However, a pump with a dry rotor also has disadvantages:

vibration and noise levels are quite high;
As a result of the rapid use of the lubricant, it requires regular maintenance.

3 What to pay attention to?

Before you start choosing a pump for your heating system, you should decide what characteristics it should have. What kind of apparatus is needed for heating a private home and what to pay attention to in order to make the optimal choice of a circulation pump for the heating system:

The circulation pump can be installed in two ways. This also affects the selection of a heating pump.

It is built directly into the boiler - it is observed in many modern models.
The pump is welded in as a separate part of the heating circuit. It is used more often in older models of heating boilers. Water circulation in the systems occurred due to the difference in density and mass of cold and hot coolant. Pipes in such systems were placed at a slope. The introduction of a circulation pump into such a system increases the speed of movement of the coolant and, therefore, the space is heated faster.

In the question of how to choose a pump, the characteristic features of the heating system are also taken into account.

Type of heating system. For networks with natural circulation, it is recommended to install a device with a wet rotor with a power of up to 50-60 watts. If the circulation is forced, a more powerful unit is needed up to 80 W if there is a slope, and up to 90 W without a slope.
Heated area and volume of coolant. The higher these parameters, the more powerful the mechanism required. To calculate the exact power of the device, it is recommended to contact a body technician.
Restriction on the maximum noise level. For heating a private house, where there is no separate room for the pump at a sufficient distance from the living rooms, it is not recommended to choose devices with a dry rotor.
Technical condition of the heating system. Any pump will fit the new heating system. For systems that are 15-20 years old or more, it is necessary to take into account the presence of impurities in the liquid. 25-35% is added to the calculated power, especially when choosing a device with a wet engine. However, for older networks, a device with a dry rotor is better suited, because it is less sensitive to the quality of the liquid.

4 How to choose the right pump?

To choose the right circulation pump for a heating system, you need to consider that the device must meet certain criteria:

In the last point, the wet type pump undoubtedly wins, it is smaller and quieter. But other criteria need to be sorted out.

4.1 Calculation of pump performance

The performance of the pump implies the amount of coolant distilled and its consumption at the lowest load of the device. The higher the performance, the better.

Calculation of the pump according to the performance criterion can be done using the formula: Q = N / (t 2 – t 1), where Q is the desired performance value, N corresponds to the power of the heating boiler, t1 is the temperature of the liquid in the "return" of the circuit, t2 is the temperature in the supply compartment, after the heating boiler.

Using this formula, you can approximately select the parameters of the required pump. It is believed that approximately 0.6 m of pump pressure is required per 10 m of the circuit ring.

4.2 Device pressure

The pressure of the device is the level to which the device can raise the water in the heating circuit. Usually this parameter is indicated in the documents for the mechanism and on the pump itself.

For example, heating pumps model GRUNDFOSUPS25-40. The numbers in this stamp mean:

40 – height of liquid rise – 4 m or 0.4 atm. pressure. This value is taken into account first of all when choosing a pump.
25 – diameter of connected pipes – 25 mm. Typically, pipes with a diameter of 32 and 25 mm are used.

Therefore, when wondering how to choose the right circulation pump, you should take into account the full name of the pump. It must match the diameter of the system pipes. The pump also indicates the power consumption, the direction of rotor movement, and the number of revolutions.

4.3 External aspects

The operation of the device and the required amount of heat also depend on the ambient temperature. An incorrectly selected pump may begin to overheat because it may not be able to cope with excessive load. This means that before calculating the necessary parameters of the device, you should be well aware of the characteristics of the boiler and heating system.

For pipes with a larger diameter, the circulating coolant will be larger and, therefore, a more powerful pump will be needed. For coolant made from non-freezing liquid, as a rule, a pump should be selected that is more efficient and reliable.

4.4 Power calculation

The power of the circulation pump for heating depends on the area of the room that is heated. For example, the area is 200 m2. To keep the building warm, an approximate ratio is followed: 1 kW of thermal energy per 10 m 2. Therefore, this area will require 20 kW.

Next, you should calculate the temperature difference between the supply and return circuits. Experts advise within 10ᵒC. Calculate the power: 20:10=2. The parameter calculated in this way is the pump power, measured in m 3 /h.

The circulation pump is also calculated based on the parameters of the amount of heat required, pipe resistance, power consumption, and temperature limit.

How to choose a circulation pump for heating to make the system work most efficiently? To make the correct selection, you should take into account many factors, parameters and characteristics of the pumps and heating system, as well as external conditions and the expected result. You can also take into account reviews about a particular brand of device. The choice is made responsibly, because the comfort in the home largely depends on it.

4.5 How to choose a circulation pump? (video)

At the moment, many private houses still use the old type of heating systems - open. In such networks, heated water flows through the pipes by gravity due to thermal expansion, which is not very convenient. Radiators farthest from the boiler in such systems heat up worse than those closest to them. As a result, heat is distributed unevenly throughout the house. A way out of this situation may be to insert a circulation pump into the system. Such equipment is not too expensive and consumes little electricity. The benefits from it can be enormous. pump into the heating system - the operation is simple, and can easily be done with your own hands.

Device

You can purchase a pump at any store that specializes in selling equipment for various types of engineering systems. Its design is quite simple. An electric motor is housed in a stainless metal housing. An impeller is attached to its shaft. It is she who moves the water through the pipes.

Varieties

There are two types of circulation pumps:

"Dry." This type is most often installed in heating systems of multi-storey buildings. Such pumps are very noisy and have a lot of power. They are usually installed in separate rooms.
"Wet." These ones spin right in the water. This is not very powerful, “quiet” equipment. If the owners of a country house have decided that installing a circulation pump in the heating system of a private house is necessary, they should think about purchasing just such a model.

How to choose

When purchasing a circulation pump, the first thing you should pay attention to is the output pressure. It is very easy to define. To do this, the total length of the water pipe must be divided by 10 and multiplied by 0.5. Issued is indicated in the technical passport (in meters).

Where is it installed?

The circulation pump should be installed in such a way that access to it in the future is free. After all, like any other equipment, it can fail. In this case, it will need to be repaired or replaced.

The pump into an open heating system (as well as into a closed one) is carried out on the return pipe. In this case, a less hot coolant will pass through it. This can significantly extend its service life. Only the most modern models made from materials resistant to elevated temperatures can be installed on the supply line.

It is best to install the pump in an open heating system on a bypass. This scheme is the most convenient. The system can simply be switched to natural circulation mode.

In closed heating systems, the circulation pump is usually installed in close proximity to the expansion tank. When open, you can put it anywhere. But the best option is still installation next to the boiler.

What else do you need to buy?

In addition to the pump itself, home owners will have to buy a coarse filter. This equipment is installed on the bypass directly in front of the pump itself. It is imperative to embed it. Otherwise, the impeller will quickly become clogged with silt or scale. Water even in very clean wells contains various kinds of impurities. In addition, home owners who decide to carry out such a procedure as an open type need to purchase:

Shut-off valves. You will need two high-quality ball valves corresponding to the pump power (3/4 or 1) and one with a diameter equal to the same return line.
American, 2 limit switches necessary for inserting the valve into the main line and two for the pump itself.
Tow, mounting clamps for taps, nipple for filter.

Installation step by step

Installation into the heating system begins with pumping out the coolant. Further installation is carried out as follows:

A tap is installed into the return pipe.
They perform the actual operation of assembling the circulation pump assembly. It must be built into the heating system strictly horizontally (shaft location). Also, during installation, make sure that the terminal box is located on top. To install, take a ball valve and wrap tow on its threads, coat it with paint and screw on the filter.
Screw on the nipple and the detachable connection that comes with the pump in sequence.
A connection is screwed onto the second tap through tow.
Next, the second parts of the connections are installed on the pump.
After the pump unit has been assembled, you can begin installing it into the main line. To do this, pipe sections are inserted into the taps located on both sides.
The entire structure is attached to the main line so that the tap embedded in it is in the middle. Next, marks are made on the pipe along which holes are cut. The bends need to be welded into them.
At the final stage, the system is filled with water and pressure testing is carried out.

The installation diagram of the circulation pump in the heating system is shown in the figure below.

Expansion tank

This element is required in the heating system. After all, the volume of water pumped into the main when it heats up and cools down can change significantly. In systems with natural circulation, open tanks are usually installed. They cost less than membrane ones and do their job quite well. In this regard, owners of private houses may have a question about whether it is necessary to change this element when performing such an operation as installing a circulation pump in a heating system with natural coolant flow.

If you lack funds, you can leave everything as is. However, it is better to replace the tank. Membrane structures have the following advantages over conventional ones:

They are installed in close proximity to the boiler, and not in the attic, which, of course, makes servicing the system easier.
When using a tank of this design, contact of the coolant with air is completely eliminated. Consequently, the internal parts of the system (boiler, pump, etc.) oxidize less and last longer.
When using a circulation pump, home owners have the opportunity to create excess pressure in the system. This is done to prevent air from accumulating in the radiators. If an open tank is included in the system design, this becomes impossible.

Operating rules

So, we have examined the technology for carrying out such a procedure as installing a circulation pump in a heating system with our own hands in all details. As you can see, this operation is not too difficult.

However, no matter how carefully the pump is installed, if the operating rules are not followed, it will not last long. To extend its service life, experts advise adhering to the following recommendations:

Do not turn on the device if there is no coolant in the system.
The volume of water in the pipes must be kept within the operating characteristics of the pump.
If the device will be idle for a long time, it should be started from time to time. This should be done once a month for about fifteen minutes.
The coolant should not be allowed to heat above +65 degrees.

Pump Inspection

Installing a circulation pump in a heating system (photos of the most suitable equipment and the process of inserting it are presented on the page), thus, is a procedure that can be performed independently. If the installation technology is strictly followed, the coolant pumping device will operate uninterruptedly. But only in the case of its periodic inspections. Moreover, this operation should be carried out at least once a month. The procedure for inspecting the pump is as follows:

The device is connected to the network and checked for the presence of extraneous noise.
The pressure of the coolant is checked.
The pump heating temperature is checked.
Threaded flanges are inspected and, if necessary, lubricated.
Check for grounding between the case and the terminal.
The pump is inspected for leaks.
The terminal box is inspected.

Correct installation of the circulation pump in the heating system and compliance by the owners with all the rules for its operation is a guarantee that it will serve faithfully for many years, and life in the house will be comfortable, including in the winter.

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 wet rotor circulation pumps are their flow (the amount of water pumped per hour), pressure (to what height the pump is able to raise water) and connecting dimensions in millimeters. The choice of a circulation pump comes down to determining the required flow in cubic meters per hour. But not only. The issue is resolved by calculations, however, for most cases of individual houses and cottages, pumps 25/60 or 32/60 can be recommended. This is true, since most home heating systems are made of polypropylene pipes with a diameter of 25 or 32 mm. And it was experimentally established that, according to the flow-pressure characteristic of pumps, a head of 60 m of water. Art. (meters of water column) is more than enough, both to completely fill the system and to create the desired flow (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 linen 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 cord 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.

To make heated water flow more cheerfully through the pipes, a circulation pump is installed in the heating systems of private houses. This solution provides tangible benefits. But the main question that concerns homeowners and is covered in this material is where it is better to install the pump and how to install it correctly. After all, the main part of the controversy and doubt is caused by the place where the unit is inserted. And at the same time, we’ll figure out how to connect it to the house electrical network with our own hands.

What are the benefits of pump heating systems?

30 years ago, so-called steam heating was common in private homes, where the coolant circulated through pipes and radiators by gravity, and the heat source was a gas boiler or wood stove. Pumps for pumping water were used in district heating networks. When compact circulation pumps for heating appeared, they migrated to private housing construction, as they provided the following advantages:

The speed of coolant movement has increased. The heat generated by the boiler has become faster delivered to the radiators and transferred to the premises.
Accordingly, the process of heating the house has accelerated significantly.
The higher the flow rate, the greater the throughput of the pipe. This means that the same amount of heat can be delivered to rooms through lines of smaller diameter. Simply put, the pipelines have become half the size thanks to the forced circulation of water from the pump, which is cheaper and more practical.
Highways can now be laid with a minimum slope and water heating circuits can be made as complex and extensive as desired. The main thing is the correct selection of the pumping unit in terms of power and pressure created.
The household circulation pump for heating has made it possible to organize underfloor heating and more efficient closed systems operating under pressure.
It was possible to remove from view the ubiquitous pipes that run through the rooms and do not always harmonize with the interior. Increasingly, heating communications are laid in walls, under floor coverings and behind suspended (suspended) ceilings.

Note. A minimum slope of 2-3 mm per 1 m of pipeline is needed to empty the network in case of repair or maintenance. Previously, it was made at least 5 mm / 1 m.p.

Pumping systems also have disadvantages. This is a dependence on electricity and its consumption by the pumping unit during the heating season. Therefore, if there are frequent power outages, the circulation pump must be installed together with an uninterruptible power supply unit or connected to an electric generator. The second drawback is not critical; if you select the power of the device correctly, then the electricity consumption will be acceptable.

Leading manufacturers of heating equipment, such as Grundfos or Wilo, have developed new models of units that can save energy. For example, if you buy and install an Alpfa2 circulation pump from the Grundfos brand, it will automatically change its performance depending on the needs of the heating system. True, its price starts from 120 USD. e.

New generation circulation units from Grundfos – models Alpfa2 and Alpfa2L

Where to install the pump - supply or return

Despite the abundance of information on the Internet, it is quite difficult for the user to understand how to correctly install a heating pump in order to ensure forced circulation of water in the system of their own home. The reason is the inconsistency of this information, which causes constant debate on thematic forums. Most of the so-called specialists claim that the unit is installed only on the return pipeline, citing the following conclusions:

the coolant temperature in the supply is much higher than in the return, so the pump will not last long;
The density of hot water in the supply line is less, so it is more difficult to pump;
The static pressure in the return line is higher, which makes the pump easier to operate.

Interesting fact. Sometimes a person accidentally ends up in a boiler room that provides central heating for apartments, and sees the units there embedded in the return line. After this, he considers this solution to be the only correct one, although he does not know that in other boiler houses centrifugal pumps can also be installed on the supply pipe.

We respond to the above statements point by point:

Household circulation pumps are designed for a maximum coolant temperature of 110 °C. In a home heating network it rarely rises above 70 degrees, and the boiler will not heat the water more than 90 °C.
The density of water at 50 degrees is 988 kg/m³, and at 70 °C – 977.8 kg/m³. For a unit that develops a pressure of 4-6 m of water column and is capable of pumping about a ton of coolant in 1 hour, the difference in the density of the transported medium is 10 kg/m³ (the volume of a ten-liter canister) is simply negligible.
In practice, the difference in static pressure of the coolant in the supply and return lines is equally insignificant.

Here's a simple conclusion: Circulation pumps for heating can be embedded into both the return and supply pipelines of the heating system of a private house. This factor will not in any way affect the performance of the unit or the heating efficiency of the building.

Boiler room made by our expert Vladimir Sukhorukov. There is convenient access to all equipment, including pumps.

The exception is cheap solid fuel direct combustion boilers that are not equipped with automation. When overheated, the coolant in them boils, since burning wood cannot be extinguished at once. If the circulation pump is installed on the supply side, then the resulting steam mixed with water enters the housing with the impeller. The further process looks like this:

The impeller of the pumping device is not designed to move gases. Therefore, the performance of the device decreases sharply, and the flow rate of the coolant drops.
Less cooling water enters the boiler tank, causing overheating to increase and even more steam to be produced.
An increase in the amount of steam and its entry into the impeller leads to a complete stop of the coolant movement in the system. An emergency situation occurs and, as a result of an increase in pressure, a safety valve is activated, releasing steam directly into the boiler room.
If no measures are taken to extinguish the firewood, the valve cannot cope with the pressure release and an explosion occurs with the destruction of the boiler shell.

For reference. In cheap heat generators made of thin metal, the response threshold of the safety valve is 2 Bar. In higher quality TT boilers, this threshold is set at 3 Bar.

Practice shows that no more than 5 minutes pass from the start of the overheating process to the valve activation. If you install a circulation pump on the return pipe, then steam will not enter it and the time period before an accident will increase to 20 minutes. That is, installing the unit on the return line will not prevent an explosion, but will delay it, which will give more time to fix the problem. Hence the recommendation: it is better to install pumps for boilers running on wood and coal on the return pipeline.

For well-automated pellet heaters, the installation location does not matter. You will learn more information on the topic from our expert’s video:

Installation diagrams in various types of systems

To begin with, let’s clarify the place where to install the flow pump, which circulates water through the boiler and forcibly directs it to the radiators of the heating system. According to ours, whose experience is trustworthy, the installation location must be chosen in such a way that the unit is convenient to maintain. On the supply side it should be located after the safety group and shut-off valves, as shown in the installation diagram:

In order for the unit to be removed and serviced, shut-off valves must be installed on the sides

On the return, the pump must be placed directly in front of the heat generator, and in tandem with a filter - a mud trap, so that you do not have to buy and install extra taps. The wiring diagram for the pumping unit looks like this:

When installing on the return line, it is better to place the mud collector in front of the pump unit

Recommendation. A circulation pump can be installed in this way in both a closed and an open heating system, there is not much difference. The statement also applies to the collector system, where the coolant moves to the radiators through separate connections connected to the distribution comb.

A separate issue is an open heating system with a circulation pump, capable of operating in 2 modes - forced and gravity. The latter is useful for homes where power outages often occur, and the owners’ income does not allow them to buy an uninterruptible power supply unit or a generator. Then the device with shut-off valves must be installed on the bypass, and a tap must be inserted into a straight line, as shown in the diagram:

This scheme can operate in forced and gravity mode

Important point. On sale there are ready-made bypass units with a pump, where instead of a tap on the flow there is a check valve. Such a solution cannot be called correct, since a spring-type check valve creates a resistance of the order of 0.08-0.1 Bar, which is too much for a gravity heating system. Instead, you can use a petal valve, but it must be installed only in a horizontal position.

Finally, we will explain how to install and connect a circulation pump to a boiler that burns solid fuel. As mentioned above, it is better to place the unit on the line coming from the heating system to the heat generator, as shown in the diagram:

Installation rules

The design of a household circulation pump from any manufacturer provides for its fastening to pipelines or shut-off valves using union nuts (American). This allows it to be quickly dismantled if necessary, for example, for replacement or repair. When installing the pump unit, observe the following recommendations:

Place the device on any sections of pipelines - horizontal, vertical or inclined, but with one condition: the rotor axis must be in a horizontal position. That is, installation "head" down or up is unacceptable.
Please note that the plastic box with electrical contacts is located on top of the case, otherwise it will be flooded with water in the event of an accident. Yes, and it will not be easy to maintain the product. This is easy to achieve: unscrew the screws securing the casing and turn it to the desired angle.
Be aware of the direction of flow indicated by the arrow on the body.
So that the product can be removed without emptying the system, install shut-off valves before and after it, as shown in the diagrams in the previous section.

A visual aid in which position the pump unit should stand

Advice. It so happened that the load from the weight of the circulation unit will fall on 1 or 2 ball valves (depending on the orientation of the area in space). Hence the recommendation: do not save money and buy high-quality shut-off valves, whose body will not crack over time from mechanical stress.

About installing additional units

As a rule, in a closed or open radiator heating system, where the heat source is a single boiler, it is enough to install one circulation pump. In more complex schemes, additional units are used for pumping water (there may be 2 or more of them). They are placed in the following cases:

when more than one boiler installation is used to heat a private house;
if a buffer tank is involved in the piping scheme;
the heating system has several branches serving various consumers - radiators, heated floors and an indirect heating boiler;
the same, using a hydraulic separator (hydraulic arrow);
for organizing water circulation in underfloor heating circuits.

Correct wiring of several boilers operating on different types of fuel requires that each of them have its own pumping unit, as shown in the diagram for the joint connection of an electric and TT boiler. , described in our other article.

Connecting an electric and TT boiler with two pumping devices

In a circuit with a buffer tank, it is necessary to install an additional pump, because it involves at least 2 circulation circuits - boiler and heating.

The buffer tank divides the system into 2 circuits, although in practice there are more of them

A separate story is a complex heating scheme with several branches, implemented in large cottages with 2-4 floors. Here, from 3 to 8 pumping devices can be used (sometimes more), supplying coolant floor by floor and to different heating devices. An example of such a circuit is shown below.

Finally, a second circulation pump is installed when heating the house with water-heated floors. Together with the mixing unit, it performs the task of preparing coolant with a temperature of 35-45 ° C. is clearly described in a separate material.

This pumping unit forces coolant to circulate through the heating circuits of underfloor heating.

Reminder. Sometimes pumping devices do not need to be installed for heating at all. The fact is that most electric and gas wall-mounted heat generators are equipped with their own pumping units built inside the housing.

Connecting the circulation pump to the electrical network

There are several ways to connect power to the device:

through a conventional differential machine;
with thermostat control;
connection to the network together with an uninterruptible power supply unit (UPS);
powering the unit from the boiler automation.

Warning. Often, homeowners simply plug the pump into a regular outlet, connecting the wires to a purchased plug. We cannot recommend this approach, because connection without grounding and a safety circuit breaker is dangerous. If there is a problem with the device or if it is filled with water, you risk receiving an electric shock.

Typical connection diagram with differential circuit breaker

The first connection scheme is quite simple and any user can assemble it with his own hands. You will need an 8 A differential circuit breaker, wires and contacts. Connect to ground in this circuit as well as in all others.

To automatically stop the movement of the coolant when cooled to a certain temperature, an electrical circuit for connecting a circulation pump with a thermostat is used. The latter is attached to the supply pipe and breaks the power supply when the water temperature drops below the set value.

Connecting a phase wire to the pump through an overhead thermostat

Attention! So that the thermostat does not lie and turns off the circulation in time, it must be attached to the metal section of the line. Polymers do not transfer heat well, so when mounted on a plastic pipe, the device will not work correctly.

There are no difficulties in connecting the power supply through the UPS, for which the latter has special connectors. It is also worth connecting the heat generator itself to them, if it needs electricity. But connecting the pump to the boiler control panel or to its automation is a more complicated procedure. It is advisable to have knowledge and skills in the field of electrical engineering.

The boiler is also connected to the uninterruptible unit if it needs electricity

At what speed should the pump in the heating system operate?

The purpose of forced circulation is to effectively heat the house through the reliable delivery of heat to all consumers of the system, right up to the furthest radiator. To do this, the pumping unit must develop the required pressure (otherwise known as pressure), which is ideally calculated by design engineers based on the hydraulic resistance of the pipeline network.

Most household pumps have from 3 to 7 rotor speeds, due to which the performance and pressure generated can be increased or decreased. In order not to torment you with hydraulic calculations, we offer the following method for selecting the optimal speed:

Find a laser surface thermometer (pyrometer). Put the heating system into operating mode.
Measure the surface temperature of the pipe at the inlet and outlet of the boiler.
If the temperature difference is more than 20 °C, increase the rotor speed. After 30 minutes, repeat the measurement.
When the temperature difference is less than 10 °C, the water flow rate must be reduced. The goal is to achieve a delta between supply and return of about 15 °C.

The minimum number of rotor speeds is 3, but sometimes 7 or more

Advice. Do not switch the pump to a different circulation speed "on the fly". Disconnect it from the network, move the regulator to a different position, and then put it back into operation.

You can do without a pyrometer when thermometers are installed on the supply and return lines. If the adjustment limits do not allow you to enter the range of 10-20 °C temperature difference, your system is not working efficiently due to an incorrectly selected circulation pump. Too cold return water increases the load on the boiler and increases fuel consumption. Water that is too hot means that it flows too quickly and does not have time to transfer heat to the heating devices.

The leading European brand Grundfos offers the latest generation Alpfa3 circulation pumps, which can independently select performance depending on the load and thus adapt the work to changing conditions. With their help, you can even balance the heating system, which our expert will tell you about in the next video:

Conclusion

Now you know how to properly install a circulation pump in a water heating system and connect it to the power supply of a country house. This will save you from making all sorts of mistakes that lead to minor and major troubles. Again, you can do the installation and piping of the unit with your own hands. The only difficulty is to embed it in a section of steel pipeline. But there is a way out: find a set of tools for manually cutting pipe threads, cut out a piece of pipe with a grinder and mount the pump unit.