The bypass and the need for its installation when organizing single-pipe or two-pipe heating systems are due to the improvement in the quality of heating of premises in a private house or high-rise apartment. Why do you need a bypass: this is a metal or plastic pipe in the form of a jumper that bypasses one or another heating device. The installation of a bypass itself creates options for redirecting the coolant bypassing the devices being replaced or repaired without turning off the heating in the house. A jumper from a section of pipe to redirect liquid bypass is designed uncontrolled (open), with a valve, or automatic.

The device can serve various mechanisms - heating system pump, pressure gauge, radiator, manifold, underfloor heating pipeline, etc. Bypass is especially important for the uninterrupted operation of the pump - with the correct slope of the pipes, the principle of natural circulation will temporarily replace the pump being repaired, and the heating will not be turned off. It is important to tie radiators with a pipe jumper, especially in a single-pipe circuit, and when including bypass valves in the circuit, a bypass valve is simply necessary. And the last application of the device is to work in the collector unit of two-pipe circuits when mixing supply and return at the inlet or outlet of the boiler.

The jumper can be installed in pipelines made of metal-plastic, polypropylene, steel, cast iron, brass or copper. You can buy the device or make it yourself, but it is not advisable to use metal steel pipes, as they rust and clog the coolant. The best option is heating and bypass made of polypropylene: such a pipeline will work reliably and for a long time.

What is a bypass for and how does it work?

The single-pipe heating distribution scheme is still in demand in individual construction, but in old multi-storey buildings this solution was often used, so installing a bypass pipe was considered a non-discussable and necessary option.

Special purpose:

1. Ensuring uninterrupted operation of individual components of the heating system without turning off the heat. Repair or replacement of mechanisms, equipment and individual elements in the heating system is facilitated by the fact that the inlet and outlet shut-off valves (supply and return) of the coolant are closed, and the working fluid is redirected through a jumper pipe, as a result of which the broken unit can be easily dismantled or repaired. This is why a bypass is needed in a heating system, but this is not the only purpose of the bypass;
2. The functioning of a single-pipe heating system can be improved, since it has a significant drawback: the temperature from the heated coolant is unevenly distributed over the radiators due to their sequential connection scheme. Thus, the temperature in the very last radiator will always be the lowest. To obtain the same temperature on all batteries, install a bypass in front of each heating device - radiator, battery or register. Here, the purpose of the bypass is that a certain volume of media is directed bypassing the radiator sections, and gets hot even into the furthest battery. In this case, the diameter of the pipe jumper in a single-pipe heating system must be equal to or less than the diameter of the pipes of the main circuit;
3. Maintain the operation of heating systems during an emergency power outage, since the circulation pump does not function, and the presence of a bypass will make the movement of coolant uninterrupted.

Important: Homeowners often wonder if a bypass is needed in a two-pipe double-pipe heating system? With this pattern of movement of the working fluid, the bypass, after closing the valve, will redirect the coolant to those areas that lose heat the most.

Device classification

Bypasses are divided according to the type of shut-off valve and functional purpose. According to the types of locking devices in the circuit of different heating systems, the contours are:

1. Inclusion in a system with a shut-off valve that manually opens or closes at the right time. It is recommended to install the valve, which can be three-way or ball, in the center of the pipe;
2. A jumper with a valve is an automatic device that operates autonomously and does not require outside intervention. An automatic heating valve is a rubber or silicone unsinkable ball. Such a bypass valve only works in conjunction with the pump: when the electric motor is turned on, the valve opens under the pressure of the working fluid, and when the pump is turned off, it closes, stopping the movement of the coolant.

Important: in order to install a bypass with an automatic valve in the heating system of polypropylene pipes, it is necessary to monitor the origin of the working fluid: it must be absolutely clean, free of scale, debris, rust, etc. Any solid particles can deform the ball, causing the valve to leak fluid.

According to their functional purpose, bypasses are classified as:

1. Radiator jumper located at the entrance to the radiator for scheduled or emergency shutdown of the device without stopping the heating;
2. Pumping bypass: installed simultaneously with the pump to turn off or change its operating mode. If the bypass pipe is installed correctly, then failure of the pump is impossible;

Bypass installation - conditions and methods

To install the bypass bypass pipe in a polypropylene pipe heating system correctly, follow the following recommendations:

1. The diameter of the bypass pipe is taken to be smaller than the diameter of the pipeline;
2. The jumper should be located as far as possible from the main riser and as close as possible to the device being served;
3. The bypass is mounted in a horizontal position to avoid air pockets;
4. The bypass section of the pipe can only be installed after the coolant has been drained.

The first method of installing a jumper for a radiator is welded. The inclusion of polypropylene in the heating system ensures maximum reliability of the circuit, but steel pipes can also be used, albeit with less efficiency. PVC or metal pipes for the bypass are drilled in the right place, a jumper pipe is inserted into the hole, and the joint is welded. A ball valve is installed in the place where the radiator was previously connected. The last stage is installing the radiator in a new place, fixing the device and connecting it to the heating.

The second method is coupling. The radiator is also dismantled, the jumper is secured in place using factory couplings, and shut-off valves are cut into the edges of the bypass. In the same way, the radiator is attached and connected to the circuit in a new location.

Bypass in the "warm floor" system

How to properly install a bypass in a “warm floor” scheme needs to be described in more detail, since the temperature of the coolant with such a solution should not be more than 45 ° C. Installation of a heated floor involves the installation of a collector, and a bypass jumper on it acts as a bypass section of the heating route and a mixing unit.

The mixing unit in the manifold is a three-way valve with a temperature sensor. The valve divides the coolant flow into two parts, one of which it directs into the pipes of the “warm floor” device, and the second through a parallel line. In this case, the supply and return are mixed, after which the working fluid flows back into the boiler jacket.

Before you make a bypass along a small circuit, you need to understand that a jumper through a three-way valve will connect the supply and return, that is, the collector must be included in the underfloor heating circuit. The bypass works in this scheme as follows: after starting the boiler, the three-way valve shuts off the flow of cold working fluid from the heating main to the heat generator.

After the coolant heats up to the set temperature (45-50°C), the automatic valve will open and allow a certain amount of hot coolant to flow into the return pipe. This technique allows you to avoid the accumulation of condensate in the combustion chamber and on the surface of the boiler jacket.

A metal or PVC piece of bypass pipe is necessary in any heating scheme, since its use is an economical option for distributing heat with high efficiency while saving solid, gas, liquid or electrical energy. Simply put, the volume of coolant supplied to radiators and other devices and devices is reduced when a bypass is installed, without violating the norms for calculating heat transfer of both individual elements of the system and the entire structure.

Bypass for heating

We have previously talked about. Today we will dedicate an article to single-pipe circuits, or more precisely, the importance of a bypass for heating. Let's figure out what it is and why it is needed. We will consider several options for installing a bypass in a single-pipe heating system separately, since each of them has different requirements. At the same time, its functions remain unchanged, which cannot be said about its location in space and relative to other equipment, as well as its diameter.

Why do you need a bypass?

A bypass is a bypass, an ordinary section of the main line, which must be installed at the required key points of the circuit. It’s worth noting right away that bypass for heating is used only in single-pipe circuits. The difference between a one-pipe heating circuit and a two-pipe one is that in the first, the coolant circulates through one line. It starts from the boiler room and ends there, while the water passes through a chain of radiators, in each of which it gives off part of its heat.

The key point that distinguishes the two-pipe scheme is the fact that the supply and return flows are separated. Therefore, a bypass in a two-pipe heating system is simply not needed. While in a single-pipe circuit, the supply and return are inseparable and are a single flow. The bypass is installed in single-pipe circuits, which can be located in different planes:

• vertical;
• horizontal.

Based on this, the installation of a bypass in the heating system is also different. Vertical contours are installed in buildings whose height is more than one floor. Horizontal - in one-story houses and apartments. To understand the principle of operation of the bypass, let’s consider its action at different points of the installation. Where can a bypass route be installed:

• on a pump that pumps the coolant flow;
• on radiators.

In both cases, the bypass path serves to ensure that circulation in the heating circuit does not stop even if the above equipment breaks down. Why is a bypass needed in a heating system? This is a backup channel through which the coolant continues its circulation along the circuit and thereby prevents . Let's look at the principle of operation of the bypass for each of the above installation options separately.

Installation on the pump

Bypass for circulation pump with ball valve

Why is a bypass needed in the heating system in the area where the electric pump is installed? It would be more accurate to say that the pump is installed directly on it. This is practiced when an electric supercharger is installed in a gravitational circuit, one in which circulation is carried out by gravity. It increases the flow rate and thus the efficiency of the circuit becomes higher. This is due to the fact that at a higher speed the coolant reaches the outermost radiator with less heat loss.

There are two options for installing a bypass for the circulation pump:

• to a new circuit;
• onto an existing circuit.

There is no difference in installation. What you need to pay attention to is the presence of shut-off valves on the central line between the bypass pipes. This is necessary to ensure that the coolant passes through the bypass for the circulation pump, and also to prevent the creation of reverse flow.

It is imperative to install a ball valve, and not a check valve, as some plumbers do.

To understand why, let's look at how it works step by step:

• when the pump operates, it accelerates the coolant;
• water from the bypass enters the main line and begins to move in both directions;
• in one direction (the desired direction) it goes unhindered, and in the second side it encounters a check valve;
• the valve closes and thereby prevents circulation in both directions.

That is, the water after the pump puts more pressure on the valve plate than before it, since the speed of the coolant behind the pump will be higher. As planned, when the pump is turned off, the coolant stops putting pressure on the check valve and does not close it. This allows water to circulate by gravity along the main line without entering the bypass. In practice, a heating bypass with a check valve does not work as expected.

The fact is that the check valve plate creates a strong hydraulic resistance equal to one meter. In a gravity circuit, the coolant simply cannot withstand such valve resistance and circulation will stop.

Therefore, before installing a bypass in a heating system with a check valve, you need to understand that in fact, installing a pump on the bypass will not make any sense. With such success, it could be installed directly on the main line, while deliberately abandoning the possibility of using the heating circuit autonomously. Is a bypass needed in the heating system in this case? It turns out that no.

If, instead of a check valve, you install an ordinary ball valve, then you yourself will be able to control the vector of water circulation along the circuit. Let's look at how to make a bypass into the heating system on which the pump will be installed. In this scheme, it consists of individual elements:

• threaded pipes that are welded into the main line;
• ball valves - installed on both sides;
• corners;
• coarse filter - placed in front of the pump;
• two American ones, thanks to which the pump can be removed for inspection or repair.

If you make a bypass in the heating system with your own hands, it is important to ensure the correct location of the pump on it. The impeller axis should be horizontal, and the terminal box cover should look up. If the terminal box cover faces down when installed correctly, its position can be changed by unscrewing the four bolts on the housing. This arrangement is necessary so that there is free access to the terminals responsible for power connections, as well as to prevent coolant from entering them in the event of a leak.

Installation on a radiator

Bypass on the heating radiator

In the area where the battery is located, a bypass is installed in a single-pipe heating system so that if circulation in the radiator stops, water can flow freely further along the circuit. In a vertical scheme, the radiator is connected to the riser by two pipes. The bypass on the heating radiator connects these pipes to each other and is installed in front of the battery. There should be no shut-off valves between the central line and the bypass in order to eliminate the human factor or the possibility of blocking the circulation in the event of a valve breakdown.

Functions of the bypass installed in front of the radiator:

• ensuring continuous circulation along the main circuit ring;
• coolant temperature regulation.

In single-pipe circuits, the coolant passes through the radiators, giving off some of the heat, and is drawn into the further flow. Accordingly, the coolant reaches each subsequent radiator a little colder.

Installing a bypass for heating makes it possible to mix the coolant from the central line with that which has passed through the battery, thereby increasing its temperature.

It turns out that if our water was 80 degrees before the first battery, then after it it will cool down to about 70 degrees. The coolant that passes through the bypass does not suffer such heat loss, therefore, when mixing liquids, the temperature of the total flow rises to approximately 75 degrees.

The horizontal single-pipe heating circuit works on the same principle, only the circuit in it is in a horizontal position in the area under the battery. At the same time, for proper circulation it is necessary to select the required bypass diameter in the heating system.

Bypass diameter

Diagram of pipe sizes in a system with a bypass on the radiator

So, we already know why a bypass is needed in a heating system and where it is installed. It remains to figure out what diameter it should be. We must consider options for installing the heating system bypass on the battery and pump separately, since its diameter will be different in each case, which is determined by different requirements for it.

The bypass on the pump will have a smaller or the same diameter as the main line. How to properly make a heating bypass, there is no fundamental difference in this case. After all, it is installed only so that if the pump is turned off, circulation can continue by gravity.

Accordingly, it is impossible to narrow the line itself, and the diameter of the pipes that extend from the circuit is not of key importance. When the pump stops, circulation through it will be impossible, therefore, even if the diameter is equal to the common line, the bypass will not change the vector of movement of the coolant. And when we need water to flow through the pump, we simply block the path of the coolant with a ball valve installed on the line.

But when installing a bypass in the heating system of a private house on radiators, its diameter is of great importance. It should be one size smaller than the pipes connecting the radiators to the central line. In this case, the leads to the batteries should also be one size smaller than the main circuit. How it works:

• water flows along the circuit and reaches the area where the batteries are installed;
• encountering a branch, the coolant changes the vector of movement in the direction where the resistance is less;
• part of the coolant continues to move along the same vector.

If the diameter of the pipes is the same as the bypass, then a small amount of water will enter the batteries, and accordingly, the temperature of the radiators will drop. If the diameter of the pipes is smaller than the diameter of the bypass, the circulation in the battery will stop altogether.

Reducing the diameter of the pipes in relation to the main line increases the speed of the coolant, which allows it to move more intensively through the radiator. In this case, water circulates throughout the battery, as a result of which it warms up evenly.

For example, consider a bypass device in. If the diameter of the main line is 32 mm, then the cross-section of the pipes through which water enters the batteries should be 25 mm. The diameter of the bypass in such a scheme, accordingly, should be 20 mm. In this case, the coolant will flow to the outermost battery along the path we need with minimal heat loss. This will make it easier to balance the system.

In modern construction, when installing heating systems, a bypass is necessarily used. This element significantly simplifies the maintenance and repair of any elements of the heating system, and also has a positive effect on the efficiency and economy of heating. This article will discuss how to properly install a bypass in a heating system.

Bypass device

A bypass is a bypass part of the pipeline that ensures the coolant moves along a path that bypasses a certain section of the pipeline. One edge of the circuit is connected to the supply pipe, and the second to the return pipe. Various elements of the heating system, such as pumps, are usually installed on the bypass.

At the connection point between the bypass and the inlet pipe of the device that needs to be bypassed, a shut-off valve is installed. Its presence makes it possible to direct the flow of liquid parallel to the device itself and regulate the intensity of the coolant supply. A valve is also installed on the return pipe, which allows you to exclude a section of the pipeline from the system without the need to stop it.

Types of bypasses for heating

When installing a bypass, shut-off valves are installed not only on the pipes of the connected device, but also on the bypass itself. The type of fittings used allows us to classify several types of bypasses, each of which is suitable for certain operating conditions.

The following types of bypasses exist:

• Unregulated;
• With manual control;
• Automatic.

The characteristics of devices with different types of shut-off valves have significant differences, so before installing a bypass in the heating system, you need to carefully consider each type.

Unregulated bypass

The device of unregulated bypasses is a simple pipe that does not have any equipment. The pipe is constantly in an open state, and the liquid moves through it arbitrarily, that is, there is no opportunity to influence the intensity of the water flow. Unregulated bypass pipes are most often used to connect heating appliances.

When designing a heating system, it is necessary to take into account the fact that water always moves primarily through those areas where the hydraulic resistance is minimal. In the case of a bypass, this means that the internal diameter of its vertical section must be smaller than the internal cross-section of the main pipeline. If this requirement is not met, the coolant will simply gravitate toward the bypass.

When designing horizontal heating distribution, other rules apply that must be taken into account before making a bypass into the heating system. The heated coolant has a reduced specific gravity and always tries to move upward. In order for the system to operate normally taking into account this rule, the diameter of the lower part of the bypass must match the diameter of the main line, and the cross-section of the pipe leading to the radiator must be smaller.

Bypasses with manual adjustment

Bypasses that are adjusted manually (manual bypasses) are equipped with ball valves. The use of ball valves is determined by the fact that they do not change the pipeline capacity at all when switching, since the hydraulic resistance in the system does not change. This quality makes the ball valve an optimal option for bypass.

Shut-off valves of this type allow you to regulate the volume of liquid that passes through the bypass section. When the tap is closed, the coolant moves in full along the main line. The operation of ball valves has one important nuance - they need to be turned regularly, even if there is no need to adjust the system. This is due to the fact that with prolonged stagnation, the taps can become tightly stuck and will have to be replaced. Sometimes a heating system feed valve is also installed, which plays a significant role.

Manual bypasses in heating systems can be used in several ways. Most often they are used to connect batteries to a single-pipe main, as well as for piping circulation pumps.

Automatic bypasses

Bypasses with automatic adjustment are usually installed in the piping of a pump installed in a system with natural coolant circulation. Such heating systems can operate independently, but thanks to the pump, the speed of fluid movement along the circuit increases, which reduces heat losses and increases heating efficiency.

The presence of an automatic bypass in the pump piping allows the system to independently regulate its operation, i.e. no human intervention required. When the pump is running, the coolant passes through it, and the bypass is closed at this time. When the pump stops, the bypass opens and the liquid moves in it, while the stationary pump impeller cuts off the coolant flow.

Automatic bypasses are divided into two types:

• Valve;
• Injection.

The design of the first type of device contains a check ball valve. The hydraulic resistance of the valve is minimal, so the liquid easily moves on its own. When the pump is turned on, the coolant begins to move faster, is transported into the main line and diverges in two directions.

Further movement of the liquid occurs without any obstacles, and the reverse flow is blocked by the valve. The operating principle of the valve itself is extremely simple - the hydraulic pressure on the outlet side exceeds the inlet pressure, so the ball is pressed closely against the seat of the structure and does not allow the fluid to move.

Valve bypasses are quite convenient and simple, but they are very demanding on the quality of the water with which the heating system is filled. If the water contains various impurities, such as rust or scale, the valve very quickly becomes dirty and becomes unusable, as a result of which it has to be replaced.

Injection bypasses are devices similar in principle to a hydraulic elevator. A pumping unit is installed in the main line, which is connected to the main circuit using pipes of smaller diameter. With this scheme, both pipes are inserted into the main pipeline.

When the pump starts, some of the liquid enters the nozzle and is passed through the apparatus, accelerating many times in the process. The outlet pipe, which is slightly narrowed and visually resembles a nozzle, which ensures efficient pumping of liquid, also works to increase speed.

A vacuum is created behind the outlet pipe, due to which the coolant begins to be sucked out of the bypass. The flow, moving under pressure, pulls all the liquid with it, and it continues to move along the main highway with noticeable acceleration. This effect allows you to completely prevent the possibility of reverse flow of liquid.

The technology described above only works when the pump is turned on. If the pumping equipment is turned off, then the coolant in full passes through the bypass under the influence of gravitational forces.

Bypass purpose

The main function of any bypass is the ability to keep the heating system in working order even if one of its elements breaks down or there is a power outage. Devices connected via bypass can be disconnected from the system without any problems - to do this, you just need to turn off both taps, and the coolant will flow around the circuit.

Thanks to the bypass, heating can continue to operate in any case, and damaged elements can be repaired, spending any amount of time. The reliability and ease of maintenance of the heating system with a bypass increases many times over.

In autonomous heating circuits, the bypass is used to solve the following problems:

• Connecting heating devices to single-pipe wiring;
• Pumping equipment piping;
• Connecting the water heated floor distribution manifold;
• Formation of a small circulation circuit when using solid fuel heating equipment.

The bypass installation method may vary depending on its purpose in a particular heating system.

Bypass for radiator

In single-pipe heating systems, batteries are best connected using a bypass. For two-pipe circuits and manifold distributions, bypasses are not needed, since all heating devices are connected in parallel, and each of them receives coolant at the same temperature. If one of the batteries fails, it can always be removed without turning off the heating system (of course, if there are shut-off valves).

In systems with single-pipe wiring, the batteries are connected in series, so the coolant in each subsequent device cools down. The result is obvious - distant devices receive much less heat, and there can be no talk of any uniform distribution of thermal energy.

Bypasses can solve the problem. The supply and return circuits are connected by a jumper, which ensures independent flow movement. The hot coolant enters directly into the radiator, while the other part of it passes further and at the outlet is mixed with cooled water from one radiator. This scheme allows you to deliver much more heat to subsequent heating devices.

Connecting the pump via bypass

It is advisable to connect the circulation pump via bypass only in those systems that were originally designed for natural circulation, i.e. they must have an accelerating manifold, pipe slopes must be observed and their diameters must be correctly selected. The pump in such systems is not intended to ensure their operation, but to increase efficiency.

For systems that were designed for forced circulation at the design stage, a bypass is simply irrelevant. Such systems operate only due to the pump, so when it is turned off, the circulation of the coolant simply stops. Bypass in this case will not solve the problem.

When connecting the pump via a bypass line, it becomes possible for counterflow in the bypass. In addition, a closed circulation loop is formed between the pump and the bypass itself. In order for such a circuit to function normally, the bypass device must be equipped with a ball valve or check valve.

When the pump is running, the device blocks the flow of liquid through the bypass pipe. The valve does this work automatically, but the tap has to be adjusted manually. When the pump stops, the bypass opens, which allows coolants from different circuits to mix. A similar scheme is not applicable in the case of injection bypasses - they completely eliminate the possibility of reverse coolant flow.

For heated floors

When installing a heated floor, it is imperative to install a mixing unit, in which a bypass pipeline is always built in. The bypass in this case will be used to ensure the normal operation of the heated floor, and without this element the heating will not be able to function.

It's all about the operating temperature, which must be maintained in heated floors. The coolant in the supply circuit can heat up to 80 degrees, but in a heated floor its temperature should not exceed 45 degrees. The liquid is brought to the required temperature in a mixing unit, which passes only the required volume of hot water. The entire remaining flow is directed to the bypass, where it is connected to the coolant from the return circuit, and returns to the boiler.

For systems with solid fuel boiler

When used in combination with solid fuel heating equipment, the bypass allows the formation of a small circulation circuit. To do this, the bypass pipe is installed in the supply, where there is a coolant heated to the limit, and is connected to a three-way valve located on the opposite side of the structure.

Thanks to the valve, hot water from the bypass and cold water coming from the return circuit are mixed. As a result, a coolant whose temperature exceeds 50 degrees is returned to the boiler for the subsequent heating cycle.

The need to return warm liquid to the boiler is determined by the fact that otherwise condensation will appear on the metal walls of the combustion chamber, which will provoke corrosion and cause damage to the unit. If you supplement the system with a bypass, then these problems can be easily avoided.

Bypass installation

Including a bypass in different types of systems has its own nuances, so before making a bypass for heating, you need to understand these points.

For example, when connecting radiators via bypass, the following rules must be observed:

• The internal cross-section of the bypass should be one step smaller than the diameter of the main pipe;
• The bypass must be installed at a minimum distance from the radiator;
• When used in apartment buildings, the bypass cannot be equipped with a tap.

Installation of a heating system bypass can be carried out both when installing a new system, and when repairing an existing structure. In the latter case, before work you need to prepare a set of pipes of suitable diameter, two tees and shut-off valves.

The inlet pipe of the structure is equipped with one of the following devices:

• Ball valve, which has minimal hydraulic resistance and completely allows coolant flow;
• A valve that allows you to manually adjust the intensity of liquid flow;
• A combination of a ball valve and an automatic thermostat - this combination can adjust the operation of the system automatically.

The outlet pipe is always equipped with a ball or shut-off valve. To connect individual elements, welding or threading can be used. Regardless of the type of connection, it must be airtight. Before putting the system into operation, you need to check it for leaks.

A bypass with a pump in the heating system is installed taking into account the following points:

1. The bypass on which the pump is planned to be installed is usually part of the main line. The internal diameter of the bypass must be large enough to ensure normal natural circulation in the system. The pump is mounted on a separate pipe, the internal cross-section of which may be smaller than the diameter of the main pipeline.
2. To simplify your work, it is best to buy a pre-assembled pump unit with the necessary parameters. It is very simple to install such a structure, since all the elements are already correctly assembled and the connections are quite reliable.
3. When installing it yourself, the pump must be positioned so that the impeller axis is horizontal. The surface with the terminals to which power is supplied should be directed upward - firstly, this will simplify access to the contacts, and secondly, it will eliminate the possibility of liquid getting on the contacts if the system’s seal is broken.
4. The area with a bypass must be equipped with a check valve or ball valve, which prevents the flow of coolant in the opposite direction - this optimizes the operation of the system. Of course, before installing the bypass, you need to purchase all the components.

Before installing a bypass with a check valve for the circulation pump, you need to think carefully about the design of the future system and take into account all possible nuances.

Conclusion

The bypass is a simple design that allows you to solve a wide range of problems. The presence of this element in the heating system allows you to make all its elements independent of each other, which is very useful during setup and maintenance. Knowing how to properly make a heating bypass will allow you to create a reliable and efficient design.

When installing a heating system, it is important to create a design that will operate with maximum efficiency and will not lose efficiency due to failures in coolant circulation.

For this purpose bypass must be used: the element serves to ensure the safety and stability of the hot circuit and does not allow it to fail, even if a leak occurs on the heating radiator.

What is bypass in heating systems

A bypass is a section of the pipeline that acts as a jumper and is mounted between the forward and return pipes in order to control the uninterrupted supply of liquid.

The bypass circuit is made of the same material from which the riser is made, but a pipe of smaller diameter is chosen for this. Optionally, a check valve is installed on the “shunt” to prevent the outflow of liquid against the main circulation.

Why is this element needed in the heating system?

Most often, multi-storey buildings of older series are equipped with single-pipe heating systems, which are distinguished by their simplicity of design and low installation costs. The heating station of the building has supply and return collectors, is equipped with radiators, and in the event of an accident on one of them, the battery must be dismantled.

This situation leads to complete paralysis of the riser operation if the system is not equipped with a bypass: this element makes it possible to block the movement of the coolant using shut-off valves. As a result, the liquid will circulate through other radiators, and damaged elements can be replaced.

With the help of this “shunt” it becomes possible:

Adjust amount of coolant.

Replace batteries, repair them while the system is running without stopping it.

Speed ​​up processes draining and filling heating circuits with working fluid.

Provide circulation coolant in the forced heating system after stopping the pump.

The bypass transports water parallel to areas with shut-off valves. The bypass circuit can also be used to drain and refill the heating pipe.

A forced system equipped with this device will work even when the pump is turned off: after the power supply is stopped, it is enough to turn off the taps leading to the pump and open the central shut-off element.

In a one-pipe system

Experts do not question whether a bypass is needed in a one-pipe heating system. The answer is clear - yes. Bypass allows:

Adjust the degree of heating of radiators if you install a thermostat valve instead of shut-off valves.

Replace battery without draining the coolant and lowering its temperature.

In apartment buildings, before carrying out manipulations with the heating system, you must obtain permission from the management company employees.

In a two-pipe system

Owners of private houses are interested in whether it is necessary to install a bypass if there is a two-pipe heating system. In this case, the jumper is not necessary, since the radiators are mounted in an independent way, which allows you to disconnect the battery or replace it without stopping the heating operation.

Such a system is considered more expensive to install and requires more time to install, but due to its improved efficiency and ease of repair, it is increasingly being installed in modern private and multi-storey buildings.

You should make sure that the system is really two-pipe: some single-pipe designs look similar in appearance, but instead of a parallel pipe, there is a riser for the upper liquid supply. In such systems, it is also necessary to install a bypass.

How is a bypass installed in a heating system?

Installation of the bypass circuit can be carried out according to different schemes:

On radiators of single-pipe systems open or closed type.

Parallel to the pumping device, which operates in a gravitational heating network (gravity-flow system).

Installation as a jumper between the coolant supply and return pipes.

Installation on mixing stations nodes.

If we are talking about a high-rise building, where a heated towel rail is connected to the main hot water riser, the design also includes you need to install a bypass.

How to make a jumper and choose the right cross-section diameter

To install the “shunt” it is necessary choose the right connection point: it should be located as close to the radiator as possible, but further from the riser pipe. If necessary, the bypass can be equipped with an auxiliary tap.

Before installation, you need to carry out calculations and purchase components; It is important that the bypass diameter in a one-pipe system is one size smaller than the cross-section of the main pipes.

To install the pump unit on plastic pipes, it is assembled in advance and connected using soldered tee jumpers, and when installing on metal pipes, you first need to weld the pump bends.

When performing installation work, it is important to remember the following points:

Install mixing valve not required, since it works in collector systems where the coolant speed has already been brought to normal.

It cannot be allowed to shut-off valves overheated, since this reduces its performance properties. For this reason, reinforcement must be welded at a distance at least 20 cm from valves that may burst or become deformed.

The pump is placed so that the working shaft positioned horizontally: This allows you to reduce the gravitational load and extend the life of the device.

We invite you to watch a video demonstrating the rules for installing a bypass in a heating system:

The bypass is an important element for the functioning of a single-pipe heating system, which is indispensable when it is necessary to service, repair and dismantle radiators. Installing this component is quite possible on your own; it is only important to choose the right components, make sure you have the tools and follow the instructions.

This seemingly insignificant detail optimizes the heat transfer of the heating unit, so a bypass in the heating system is not only desirable - it is necessary. The jumper (a piece of pipe) is mounted in the thermal route parallel to the heating radiators. Depending on the tasks assigned, this component is used either as a straight section closing the supply and return pipelines, or as a bypass line.

To understand why bypass is used and what it is in heating, you should consider the options for its use:

• in the gravity network it is mounted parallel to the functioning circulation pump;
• in mixing units of various types;
• in closed and open systems based on one pipeline, the bypass is installed on heating radiators;
• it is also used as a transition between the supply and return flows, in this case a small circulation circuit is formed that accompanies the heating of the heating unit.

When it comes to mixing units, installing a bypass in the heating system is necessary to connect the supply and return, and a three-way thermostatic valve is also used here. A piece of pipe is needed to direct liquid from both lines into the valve chamber so that water with the specified temperature parameters is formed at the outlet.

The jumper, accompanied by a three-way valve, allows the mixing principle to be used in the following network sections:

• small circulation circuit in the case of a wood-burning boiler;
• a collector that distributes coolant to the heating branches of the heated floor;
• piping for heat accumulator.

In particular, a small circuit with the introduction of a bypass protects the solid fuel boiler from condensation during its heating.

The bypass unit, used in piping solid fuel units, is used as a safety element. Example: maximum heating is set, the furnace is full, and at this time the power supply stops. In such a situation, typical for domestic operating conditions, before the power supply is restored, the water in the radiators will already have cooled down. The boiler will still be hot at this time, because fuel processing continues in it. As soon as the pump turns on, the cold medium will enter the boiler jacket, as a result of which the cast iron section will burst - the resulting temperature shock will affect it. In these conditions, a pipe jumper is extremely necessary.

A similar mixing algorithm using a valve and a jumper is used in heated floors when installing a distribution comb. After reaching the temperature standard in the heating circuits, the three-way valve shuts off the supply from the boiler, the media is driven by the pump along the internal heat line through the bypass.

Heating pump with bypass

The most common scenario for inserting a pump into a water heating system is directly into the pipeline (either into the supply branch or the return branch). In this case, a bypass is not installed, since when the unit is stopped, the small diameter of the pipes will not be able to maintain independent circulation of the liquid.

A bypass is required if a gravity system is initially used. Here, the main mode of heat supply will be forced distribution of the carrier using a circulation pump. During periods of no power supply, convection will contribute to the natural gravity of the environment. This solution involves installing pumping equipment on a bypass.

The unit can be assembled in two ways:

1. The direct line is equipped with a ball valve; shut-off valves, a strainer and a pump are mounted in the bypass branch.
2. The line rupture is complemented by a ready-made kit in the form of a bypass with a check valve and a pump.

In the first case, the gravity mode must be activated manually. During a power outage, residents will have to open one of the taps in the boiler room themselves. Otherwise, stopping circulation will cause the medium to cool down.

In the second scenario, a power outage will cause the check valve to automatically activate, which remains closed while the pumping device is operating. But there are two potential problems that can get in the way:

• Some modifications of ball valves cannot be disassembled. If they fail or become dirty, you will have to dismantle and replace the entire assembly (except for the filter and pump);
• U-shaped variations serve as an additional air collector; they require periodic turning of the manual release valve.

Therefore, professionals avoid schemes based on ready-made automatic bypasses; they prefer to assemble units that include a shut-off valve. In this case, the house will become noticeably cooler only half an hour after the power is turned off, during which time the main line can be opened. Another solution is to install a bypass unit using independent components and a check valve made of brass (in which the rubber ball is not fixed by a spring).

Installing a bypass on a radiator in single-pipe heating

High-rise buildings, inhabited since Soviet times, have single-pipe heating based on vertical risers, present in all apartments. Here, the distribution of the coolant is ensured due to high pressure and increased flow rate of the medium.

In this scenario, both connections are elements connecting the radiator to a single line, and the bypass fits between them. The jumper has a slight offset relative to the axis of the riser, due to which water enters the battery rather than flowing along an easy path. The solution works like this:

1. The flow of hot water on approach to the first heating element is divided into two parts - the first enters the radiator, the second flows into the bypass.
2. After the first flow has cooled by a couple of degrees, both parts are mixed, then half is sent to the main line. As a result, the resulting mixture has a temperature approximately one degree lower than it was initially.
3. This process occurs consistently in all heating devices. All consumers of the network receive a given amount of thermal energy (ideally in equal measure), because pumps drive large volumes of water through the mains, leveling temperature differences between the first and last links.

A similar solution is usually used in two-story residential construction. Despite the fact that the vertical riser serves only a pair of radiators, it is advisable to equip the top one with a bypass. The reason is the disproportion between the performance of household and industrial circulation pumps.

If we exclude the direct bypass jumper, the full volume of the carrier, having passed through the battery, will cool down more than in the described circuit. The temperature difference will lead to the fact that each subsequent apartment will receive less and less thermal energy, the last one will practically not warm up.

This is why the bypass is so important when installing a vertical single-pipe heat supply. Two-pipe distributions are based on independent lines for cooled and hot media; a jumper is not needed here.

The low power of the circulation pump installed in a country house is compensated by the large throughput capacity and diameter of the pipeline.

Errors often encountered during self-installation

Often, home craftsmen who decide to install new aluminum radiators themselves instead of old cast iron ones make two common mistakes:

• they equip the direct bypass section with a ball valve in an attempt to direct all the heated water into the battery;
• assemble a mixing structure, adding a three-way valve to independently regulate heat transfer.

The second example, at a stretch, can be called acceptable if we are talking about individual heating; here the homeowner can individually control the output of the heating unit. In standard apartment buildings, neighbors can be vulnerable if one person unbalances the system by taking away more heat.

Finally, if a bypass is added to the design of a heated towel rail, it is intended only for the convenience of replacing and servicing this heater. The element in question does not affect heat transfer, since the pressure and speed of movement of the medium in the water supply here change to an insignificant extent.