Forced circulation heating system

Heating a house without a pump. Two proven options

Until the 90s of the last century, heating a house without a pump was the only one available, since the direction for the manufacture of circulation pumps and their promotion to the masses was not developed. Thus, the owners and developers of private houses were forced to install heating in their houses without a pump.

But when good boiler equipment, pipes and compact circulation pumps began to be brought to the CIS in the 90s, the situation changed dramatically. Everyone started installing heating systems. which do not work without a pump. They began to forget about gravity systems. But today the situation is changing. Builders of private houses again recall the heating of the house without pumps. Since everywhere you can trace interruptions and shortages of electricity, which is so necessary for the operation of the circulation pump.

The issue of quality and quantity of electricity supply is especially acute in new buildings.

That is why today, more than ever, one proverb is remembered: “Everything new is a well-forgotten old!”. This proverb is very relevant today, for heating a house without a pump.

For example, in the past, only steel pipes, homemade boilers and open expansion tanks were used for heating. The boilers were of low efficiency, the pipes were bulky steel, and it is not recommended to hide them in the walls.

Expansion tanks were located in attics. because of this, there were heat losses and the threat of a flood of the roof or freezing of the pipes in the tank. Which in turn often led to an explosion of the boiler, rupture of pipes and human casualties.

Today, thanks to modern boilers, pipes and other heating devices, it is possible to make a smart, economical heating system without a pump. Thanks to modern economical boilers, significant savings can be achieved.

Modern plastic or copper pipes can be easily hidden in walls. The same heating of the house today can be done, both with radiators and with warm floors.

Today, there are two main home heating systems without a pump.

The first and most common system is called Leningradka. or with horizontal spill.

The main thing in home heating systems without a pump is the slope of the pipes. Without a slope, the system will not work. Due to the slope, "Leningradka" is not always suitable, since the pipes run around the entire perimeter of the house. Also, due to the fact that the slope may not be enough, you have to lower the boiler below the level of your floor. The boiler in this case is inconvenient to heat and clean.

Also, when installing a heating system at home without a Leningradka pump, doorways interfere along the route of the pipes. In this case, it is necessary to make window sills with a height of at least 900mm.

This is necessary so that the radiator is mounted and there is enough height for the pipes along the slope. Otherwise, the system is fully functional, with cast iron, steel and aluminum radiators.

The second home heating system without a pump is called the "Spider" or vertical top-spill system.

Today it is the most reliable and practical home heating system without a pump. The main thing is that the "Spider" system is devoid of all the shortcomings of "Leningradka", with the exception of the slope of the return line, due to which the boiler also has to be lowered below the floor.

Otherwise, the Spider system is the most efficient system. Any radiators and underfloor heating can be screwed to the Spider system. It is possible to mount valves under the thermal head on radiators in the “Spider” system and hide pipes in the walls and so on.

Today, it is increasingly necessary to recommend the Spider system to developers, because. today it is an ideal home heating system without a pump.

Thank you for reading this article!

Pros and cons

The open heating system has not yet lost its relevance, and recently it has even experienced a rebirth, and there are reasons for this. Many homeowners are concerned about the energy independence of their communications, and an open tank scheme allows this to be achieved. It also has other advantages:

• it is easier to fill an open heating system and bleed air than in a closed one. There is no need to monitor the maximum pressure, and when filling, the air leaves the pipelines very quickly through the open expansion tank. It remains only to ventilate the radiators;
• it is easier to recharge: again, pressure control is not required, and water can be added to the container even with a bucket;
• the operation of the system does not depend on the presence of leaks: here the operating pressure is very small, so as long as there is water in the heating network, it will function properly.

As usual, there were some drawbacks, due to which such systems began to be gradually replaced by closed-type schemes with a membrane expansion tank. Due to the direct contact of the coolant with atmospheric air, 2 processes occur immediately in the tank: the natural evaporation of hot water and its saturation with oxygen. This results in the following requirements:

• it is necessary to monitor the water level in the tank and replenish it in time;
• it is impossible to fill the heating network with antifreeze, which, when evaporated, releases harmful substances.

Saturation of the coolant with oxygen leads to a decrease in the service life of the steel parts of the boiler. For the above reasons, the open system has not been used in an apartment building for a long time, although in the 60-70s of the Soviet era this practice took place in low-rise residential buildings. It is also undesirable to use it with high-temperature heat sources when the coolant is close to the boiling point. The fact is that with increased pressure in a closed network, this threshold rises, and there is nowhere for the water to evaporate. In an open system, the amount of water will quickly decrease, freeing the entire volume of the expansion tank for air.

Where to put the pump for supply or return

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

• the temperature of the coolant at the supply is much higher than at 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 pipe is higher, which makes the pump easier to operate.

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

We answer the following statements point by point:

1. Domestic 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 water more than 90 ° C.
2. 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 of 10 kg / m³ (the volume of a ten-liter canister) is simply negligible.
3. In practice, the difference between the static pressures of the coolant in the supply and return lines is just as insignificant.

Hence a simple conclusion: circulation pumps for heating can be inserted into both the return and supply pipelines of the heating system of a private house. This factor will not 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 boilers of direct combustion, not equipped with automation. When overheated, the coolant boils in them, since burning firewood cannot be extinguished at once. If the circulation pump is installed on the supply, then the resulting steam mixed with water enters the housing with the impeller. The further process looks like this:

1. The impeller of the pumping device is not designed to move gases. Therefore, the performance of the apparatus is sharply reduced, and the flow rate of the coolant drops.
2. Less cooling water enters the boiler tank, which causes overheating and even more steam.
3. An increase in the amount of steam and its entry into the impeller leads to a complete stop of the movement of the coolant in the system. An emergency situation arises and as a result of an increase in pressure, a safety valve is activated, ejecting steam directly into the boiler room.
4. If measures are not taken to extinguish the firewood, then the valve cannot cope with the pressure relief and an explosion occurs with the destruction of the boiler shell.

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

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

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

Pump Installation Recommendations

In order to ensure the normal circulation of fluid in the heating system, you need to make the right choice of the place where the pump will be installed. A place in the water suction area should be determined where excess hydraulic pressure is always present.

Most often, the highest point of the pipeline is selected, from which the expansion tank rises to a height of about 80 cm. The use of this method is possible if the room is high. It is usually practiced to install an expansion tank in the attic, provided that it is insulated for the winter.

In the second case, the tube is transferred from the expansion tank and cuts into the return pipe instead of the supply pipe. Near this place is the suction pipe of the pump, so the most favorable conditions are created for forced circulation.

The third installation option is to tie the pump into the supply pipeline, immediately after the point where water enters from the expansion tank. The use of such a connection is possible if a particular model is resistant to high water temperatures.

Selecting an open heating scheme

Installation of the boiler in an open heating system

At the first design stage, it is important to choose the right scheme for an open heating system with a pump. It depends on the parameters of the house, the required thermal mode of heat supply and financial capabilities.

Consider the main parameters that will directly affect the choice and further calculation of an open heating system:

• The total area of ​​heated premises. If this characteristic is less than 60 m² - you can install a gravity system;
• Floors of the house and ceiling height. For a gravitational system, a prerequisite is the presence of an accelerating flow. Without it, air may appear in the open heating system and circulation will deteriorate;
• Estimated thermal mode of operation. For low-temperature, an open heating system with a circulation pump is used. Otherwise, a slight expansion of the water will not create the necessary circulation.

Only after a thorough analysis of these indicators, as well as the calculation of heat losses in the house, can you decide whether to install open-type heating with or without a pump.

It is best to calculate the heat loss of a building using specialized programs. Their demo versions are distributed free of charge.

Gravity heating system

The main difference between gravity and the rest is the complete absence of any mechanisms for the forced movement of fluid through pipes. Those. This process is carried out only due to the thermal expansion of hot water.

For the correct operation of the heat supply, an accelerating riser is installed without fail. It is mounted directly after the boiler and is located vertically. Its height must be at least 3.5 m. If this condition is not met, then the heated liquid coming from the boiler for an open heating system will not have sufficient speed.

In addition to this factor, it is necessary to take into account the following specifics of the organization of an open heating system with natural circulation:

• Mandatory pipe slope. The supply line from the riser should be inclined towards the heaters. Return - to the boiler. Tilt level - 1 cm per meter;
• The boiler is located at the lowest point of the circuit;
• For normal operation, open-type expansion tanks are needed for heating systems. They are also mounted for circuits with forced circulation.

It is not recommended to install an electric boiler for an open gravity-type heating system. Just like the gas counterpart. This is due to the high probability of air pockets, which can lead to overheating of the heat exchanger.

To increase the efficiency of work in an open heating circuit with natural circulation, the diameter of the accelerating riser pipe should be 1 size smaller than the cross section of the main line.

Forced circulation in heating

Diagram of an open system with a pump

Recently, owners of private houses and summer cottages have been modernizing the heating system by installing just one component - a pump. It is designed to improve the circulation of the coolant.

In general, the arrangement of an open heating system with a circulation pump is no different from that described above.

It is important to choose the right location for the pump. It is mounted on the return pipe in front of its entrance to the heating boiler.

The optimal distance should be 1.5 m.

Scheme of the pumping unit

For this open heating scheme, the following points must be considered:

• The pump is installed on the bypass. This is necessary to ensure the circulation of water in the event of a breakdown or power outage;
• Be sure to install a check valve. It will prevent the reverse circulation effect;
• During installation, the direction of movement of the coolant is taken into account.

The advantage of using an open type heating circuit with a pump is to reduce the inertia of the system. Due to the increase in circulation, the batteries and radiators will heat up faster.

For an open heating circuit with a circulation pump, its parameters should be calculated - pressure and performance.

Combined heating classification

The essence of the phenomenon lies in the ability to use not one heating method, but several, in order, on the one hand, to reduce costs by using more economical fuel, and on the other hand, to prevent a situation in which a private house suddenly loses a heat source. It should be noted that the options under consideration are more relevant specifically for country houses and summer cottages, since city apartments, as a rule, do not provide for the possibility of such a large-scale restructuring.

Heating systems with combined heating are combined in various ways.

• Seasonal use is the most appropriate in relation to heating, where solar panels and collectors are used, since their efficiency strongly depends on the duration of the solar time of the day and the intensity of irradiation. In summer, collectors are used to heat water, and in winter - as an aid to a heating boiler.
• Use by type of fuel - depending on the availability and cost of fuel, not one specific device is installed, but several for different types, or a combined one that can work with different fuels.
• Constant - in this case, space heating involves the constant parallel operation of all heating systems. The most common, judging by the reviews, option for a private house is a combination of "warm floor" and radiator heating. The photo shows the working moment of installation.

Types of heating systems with gravity circulation

Despite the simple design of a water heating system with self-circulation of the coolant, there are at least four popular installation schemes. The choice of wiring type depends on the characteristics of the building itself and the expected performance.

To determine which scheme will work, in each individual case it is required to perform a hydraulic calculation of the system, take into account the characteristics of the heating unit, calculate the pipe diameter, etc. You may need the help of a professional when doing the calculations.

Closed system with gravity circulation

In the EU countries, closed systems are the most popular among other solutions. In the Russian Federation, the scheme has not yet been widely used. The principles of operation of a closed-type water heating system with pumpless circulation are as follows:

• When heated, the coolant expands, water is displaced from the heating circuit.
• Under pressure, the liquid enters a closed membrane expansion tank. The design of the container is a cavity divided by a membrane into two parts. One half of the tank is filled with gas (most models use nitrogen). The second part remains empty for filling with coolant.
• When the liquid is heated, pressure is created sufficient to push through the membrane and compress the nitrogen. After cooling, the reverse process occurs, and the gas squeezes the water out of the tank.

Otherwise, closed-type systems work like other natural circulation heating schemes. As disadvantages, one can single out the dependence on the volume of the expansion tank. For rooms with a large heated area, you will need to install a capacious container, which is not always advisable.

Open system with gravity circulation

The open type heating system differs from the previous type only in the design of the expansion tank. This scheme was most often used in old buildings. The advantages of an open system is the possibility of self-manufacturing containers from improvised materials. The tank usually has modest dimensions and is installed on the roof or under the ceiling of the living room.

The main disadvantage of open structures is the ingress of air into pipes and heating radiators, which leads to increased corrosion and rapid failure of heating elements.Airing the system is also a frequent "guest" in open circuits. Therefore, radiators are installed at an angle, Mayevsky cranes are required to bleed air.

Single pipe system with self-circulation

A single-pipe horizontal system with natural circulation has a low thermal efficiency, so it is used extremely rarely. The essence of the scheme is that the supply pipe is connected in series to the radiators. The heated coolant enters the upper branch pipe of the battery and is discharged through the lower outlet. After that, the heat enters the next heating unit and so on until the last point. The return line returns from the last battery to the boiler.

This solution has several advantages:

1. There is no paired pipeline under the ceiling and above the floor level.
2. Save money on system installation.

The disadvantages of such a solution are obvious. The heat output of heating radiators and the intensity of their heating decreases with distance from the boiler. As practice shows, a single-pipe heating system of a two-story house with natural circulation, even if all slopes are observed and the correct pipe diameter is selected, is often redone (by installing pumping equipment).

Two-pipe system with self-circulation

The two-pipe heating system in a private house with natural circulation has the following design features:

1. Supply and return flow through separate pipes.
2. The supply pipeline is connected to each radiator via an inlet.
3. The battery is connected to the return line with the second eyeliner.

As a result, a two-pipe radiator type system provides the following advantages:

1. Uniform distribution of heat.
2. No need to add radiator sections for better warm-up.
3. Easier to adjust the system.
4. The diameter of the water circuit is at least one size smaller than in single-pipe schemes.
5. Lack of strict rules for installing a two-pipe system. Small deviations regarding slopes are allowed.

The main advantage of a two-pipe heating system with lower and upper wiring is the simplicity and at the same time the efficiency of the design, which allows you to level errors made in the calculations or during installation work.

We make a closed heating system of a private house with our own hands

The mass construction of private houses requires the improvement of many systems - sewerage, heating, pipelines. After all, it is necessary to mount entire structures in a short time. For many years, preference was given to an open heating system. However, in recent years this trend has begun to change. Increasingly, a closed heating system of a private house is being installed. What is the difference between these structures?

Features of an open heating system and a closed

At the time of launching the open-type heating system, the performance of all structural elements should be checked. First of all, it is required to ensure uninterrupted operation of the pump. After all, it is he who ensures the circulation of the coolant in the system. The main advantage of this type of heating is the possibility of installing additional structural elements.

Closed heating system - the scheme is placed in the public domain. However, do not perform work without preliminary calculation. This also applies to the open type of heating at home. It is worth noting that a do-it-yourself mounted closed heating system has more advantages than disadvantages.

In an open structure, contact between the coolant and the atmosphere is undesirable. Unfortunately, this cannot be avoided. And as a result, air appears in the pipeline.

Complete set of water heating of closed type

During the installation of a closed heating system of a private house, it is important to ensure complete isolation from the influence of the environment.That is why it is required to carry out the installation as clearly as possible, in accordance with the scheme

The drawing also indicates the detailing and assembly of the heating structure.

1. A closed-type boiler is one of the important elements in the heating system.
2. Automatic air, balancing, safety and thermostatic valves.
3. A certain number of heating radiators (according to the estimate).
4. High quality expansion tank.
5. Ball valve and pump.
6. Do not forget about the filter and pressure gauge.

Rules for choosing a boiler for closed heating

We advise you to evaluate the power of the boiler. If you plan to heat a house, the height of the streams in which is up to 3 meters, then you select it like this: for every 10 sq. m room requires 1 kW. Of course, this is an average figure. After all, a do-it-yourself mounted closed heating system must also be reliable.

This means that there are many requirements for materials. Remember, it is better to entrust the calculations to an engineer. Only in this case the house will completely warm up in the cold.

The principle of operation of a closed heating system

It consists of 2 compartments - hydraulic chamber and gas chamber. When heated, the water enters a hydraulic-type chamber. Nitrogen is supplied to the gas compartment under pressure.

Installation of a feed line for a closed heating system

The operation of the heating system directly depends on the ability to maintain the operating pressure and volume of the coolant

It is very important that these 2 parameters are constant. Unfortunately, the creation of tightness in heating cannot be achieved in full.

Therefore, water leaks occur. Therefore, we must not forget about the periodic replenishment of the coolant.

It is worth saying that the recharge of a closed heating system consists of the following components:

1. The automatic make-up valve is located in the place where the pressure is lowest (usually before the inlet of the mains pumps).
2. A faucet crashes into the pipeline. It is also required to mount a gate valve and a controlled valve. This will allow you to control the filling of the closed heating system.
3. You can avoid accidental leakage of water into the supply line by installing a check valve. In this case, the high pressure in the closed heating system will not cause depressurization of the entire system.
4. The use of manometers is proposed as control devices. These small devices will help keep track of any changes in the heating system.

Installation of a closed heating system

1. Drawing up a scheme of the heating structure.
2. Boiler installation.
3. Installation of radiators.
4. Laying a pipeline and providing the possibility of feeding a closed heating system.
5. Placement of the pump, tank, fittings and taps. Filters are also installed at this stage.
6. Installation of pressure gauges to control pressure in a closed heating system.
7. Connecting metering devices and the boiler to the power line.
8. Starting and checking the filling of a closed heating system.

This completes the installation technology of the heating system.

Where to put

It is recommended to install a circulation pump after the boiler, before the first branch, but it does not matter on the supply or return pipeline. Modern units are made from materials that normally tolerate temperatures up to 100-115 ° C. There are few heating systems that work with a hotter coolant, therefore considerations of a more “comfortable” temperature are untenable, but if you are so calmer, put it in the return line.

Can be installed in the return or direct pipeline after/before the boiler up to the first branch

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 at the installation site.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 branch 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, as well as save on heating in two-story houses. 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 the coolant is set much less, and this allows you to burn less fuel, and without compromising the comfort of living.

There are two types of heating systems - with forced and natural circulation. Systems with forced circulation cannot work without a pump, with natural circulation they work, but in this mode they have a 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 slammed into it. This gives high efficiency and reliability of heating. It is clear that the installation of a circulation pump in these systems has differences.

All heating systems with underfloor heating are forced - without a pump, the coolant will not pass through such large circuits

forced circulation

Since a forced circulation heating system is inoperative without a pump, 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 are able to jam the impeller and stop the motor. Therefore, a strainer must be placed in front of the unit.

Installing a circulation pump in a forced circulation system

It is also desirable 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, 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 running. One ball shut-off valve is installed on the bypass, which is closed all the time while pumping is in operation. In this mode, the system works as a forced one.

Scheme of installation of a circulation pump in a system with natural circulation

When electricity fails or the unit fails, the faucet on the jumper is opened, the faucet leading to the pump is closed, the system works like a gravitational one.

Mounting Features

There is one important point, without which the installation of the circulation pump will require alteration: it is required to turn the rotor so that it is directed horizontally. The second point is the direction of the flow. There is an arrow on the body indicating in which direction the coolant should flow. So turn the unit around 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, only when choosing a model, see that it can work in both positions. And one more thing: with a vertical arrangement, the power (created pressure) drops by about 30%. This must be taken into account when choosing a model.

Open and closed heating system

If an open type expansion tank is installed, then the system is called open.In the simplest version, it is some kind of container (pan, small plastic barrel, etc.) to which the following elements are connected:

• connecting pipe of small diameter;
• a level control device (float), which opens / closes the make-up tap when the amount of coolant drops below a critical level (in the figure below, it works on the principle of a toilet flush tank);
• air release device (if the tank is without a lid, it is not necessary);
• drain hose or circuit for removing excess coolant if its level exceeds the maximum.

One of the open expansion tanks

Today, open systems are being made less and less, and all because a large amount of oxygen is constantly present in it, which is an active oxidizing agent and accelerates corrosion processes. When using this type, heat exchangers fail many times faster, pipes, pumps and other elements are destroyed. In addition, due to evaporation, it is necessary to constantly monitor the level of the coolant and periodically add it. Another drawback is that it is not recommended to use antifreezes in open systems - due to the fact that they evaporate, that is, they harm the environment, and also change their composition (concentration increases). Therefore, closed systems are becoming more and more popular - they exclude the supply of oxygen, and the oxidation of elements occurs many times slower, because it is believed that they are better.

The membrane type tank is installed in closed heating systems

In closed systems, membrane-type tanks are installed. In them, the sealed container is divided into two parts by an elastic membrane. At the bottom is the coolant, and the upper part is filled with gas - ordinary air or nitrogen. When the pressure is low, the tank is either empty or contains a small amount of liquid. With increasing pressure, an increasing amount of coolant is forced into it, which compresses the gas contained in the upper part. So that when the threshold value is exceeded, the device does not break, an air valve is installed in the upper part of the tank, which operates at a certain pressure, releasing part of the gas, and equalizes the pressure.