Bypass in the heating system: use and installation diagrams

Through the bypass in the heating system of a modern house all its key elements are mounted. This simple engineering solution facilitates the maintenance and repair of equipment connected to the trunk. It also increases the efficiency and cost-effectiveness of heating, which is not bad at all, is it?

Do you want to add a bypass to the heating system, but do not know how to do it correctly? We will help you cope with the task - the article describes the purpose of this element of the heating system and the key points of its installation.

Visual photos and available recommendations will help even a beginner to cope with the installation of a bypass. In addition, selected videos that demonstrate the step-by-step process of assembling the bypass section.

The content of the article:

  • What is a bypass?
  • Varieties of bypass heating system
    • View # 1 - Unregulated Bypass
    • View # 2 - Manually Managed Bypass
    • View # 3 - Automatic Bypass Option
  • Purpose of the bypass pipeline
    • Situation # 1 - for a radiator
    • Situation # 2 - when the pump is connected
    • Situation # 3 - when installing underfloor heating
    • Situation # 4 - in the highway with a solid fuel boiler
    • Situation # 5 - when installing bypass pipes
  • Conclusions and useful video on the topic

What is a bypass?

A bypass, or bypass bypass, is a pipeline that serves to organize the flow of coolant, bypassing a certain section of the heating line, or parallel to it.

Most often on this site is installed any equipment. One end of the bypass pipe connected to the inlet pipe, the second - to the discharge.

A shutoff valve is installed between the bypass and the inlet of the envelope of the instrument. It allows you to completely redirect the flow of water in an alternative way, or to regulate the amount of fluid flowing to the device.

In order to be able to completely shut off the equipment, a crane is installed on the outlet branch pipe - between the outlet of the device and the bypass.

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A photo of

The bypass is installed in front of the heater.

The first bypasses appeared in single-pipe heating systems, initially used only to turn off the heating device in order to replace or repair it.

Regulating aroma and bypass

In the simplest single-pipe circuits, the bypass also provided the ability to manually adjust the temperature by reducing the coolant flow.

Three-way valve with servo

In more sophisticated modern designs, bypasses are used to install three-way and four-way cranes with servo, automatically controlling the quantitative and qualitative indicators heat carrier

Bypass application in pump installation

Bypasses in heating systems are used to install circulation pumps, especially those used as backup units

Improvised Bypass for Security Group

Similarity of bypasses or a real bypass section equip a section of the system with a security group in case of repair of components

The installation of the cut-off areas

The sections of the pipeline, bypass, can be located both horizontally and vertically

Adaptation of factory performance

A bypass assembled for a circulating pump or heating appliance can be purchased in factory assembly.

Polypropylene bypass section

The cutting section of the heating system is easy to assemble with your own hands from polypropylene pipes and fittings produced for them

The bypass is installed in front of the heater.

The bypass is installed in front of the heater.

Regulating aroma and bypass

Regulating aroma and bypass

Three-way valve with servo

Three-way valve with servo

Bypass application in pump installation

Bypass application in pump installation

Improvised Bypass for Security Group

Improvised Bypass for Security Group

The installation of the cut-off areas

The installation of the cut-off areas

Adaptation of factory performance

Adaptation of factory performance

Polypropylene bypass section

Polypropylene bypass section

Varieties of bypass heating system

Valves are installed not only at the inlet and outlet, but also at the bypass itself.

Depending on the type of device used, there are three types of bypass pipes:

  • unregulated;
  • hand operated;
  • automatic.

Each type has its own design features and applications.

Simplest bypass design

In its simplest form, the bypass construction is a branch pipe with tees connected on both sides. Apply such a device when connecting radiators on a one-pipe vertical wiring diagram

View # 1 - Unregulated Bypass

The uncontrolled bypass in the heating system is a conventional bypass pipe without any additional equipment.

The lumen of the pipe is constantly open and the movement of fluid through it occurs in an uncontrolled mode. Such bypasses are mainly used when connecting radiators.

When designing a heating system, it should be borne in mind that the fluid will flow along the path with the least hydraulic resistance.

Therefore, the diameter of the flow area of ​​the unregulated bypass installed vertically must be less than the diameter of the flow area of ​​the main line. Otherwise under the influence of gravity coolant moving in the system will go to the nearest bypass.

Vertical radiator bypass

The bypass diameter of the vertical wiring should be a size smaller than the diameter of the main line. If the diameters are made the same, then the main part of the coolant will circulate along a bypass path, without reaching the radiator.

In horizontal heating wiring other laws apply. Hot medium tends to rise up, as it has a smaller proportion.

Therefore, the bypass of the lower wiring is usually made equal to the main line, and the branch pipe to the radiator is smaller.

Horizontal wiring radiator bypass

The reduced diameter of the inlet pipe of the radiator increases the pressure and contributes to a more uniform distribution of the coolant along the contour of the heat transfer device

View # 2 - Manually Managed Bypass

A bypass pipe with a ball valve installed is called a manual bypass. A crane of this type is most suitable for a bypass, as in the open state does not reduce the internal clearance of the pipeline.

Therefore, it does not create additional hydraulic resistance to fluid movement.

The use of a locking device allows you to adjust the amount of fluid passing through the bypass. If the valve is completely closed, the entire flow will follow the main path.

It should be noted that if the working elements of ball valves tend to stick to each other when the device is not used. Therefore, such a crane should be periodically rotated, even if it is not necessary.

Manual bypass radiator

It is possible to install a bypass with a tap only in the individual heating system of a private house. The use of a locking device on a bypass jumper in apartment buildings is prohibited, since it is possible by carelessness to cut off the flow of coolant to other consumers.

Scope of manually adjustable bypass in the heating system - connecting radiators single pipe line and hydraulic pump piping.

View # 3 - Automatic Bypass Option

The automatic bypass is installed in the piping of the pump of the gravitational heating system. The coolant in such a line can circulate around the circuit without a pumping unit.

An electric blower is installed in the system to increase the speed of the fluid, which contributes to less heat loss, uniform heating of the premises, and an increase in the efficiency of the system.

The redirection of fluid flow in the pump piping with an automatic bypass occurs without human intervention. When the pump is running, the coolant goes through the unit, and the bypass is blocked.

If the pump stops due to a breakdown or power outage, the coolant flows through the bypass. The immobilized impeller of the unit restricts or completely blocks the flow.

Automatic bypasses are of two types:

  • valve;
  • injection

In the first case, a non-return ball valve is mounted in the bypass pipe, which creates the smallest hydraulic resistance and practically does not interfere with the direct movement of fluid in the self-flowing mode.

When the pump is turned on, the flow rate increases. The coolant from the outlet pipe enters the line and diverges in both directions.

Further along the contour, it moves smoothly, and when moving in the opposite direction, it stumbles upon check valve.

Since the hydraulic pressure on the side of the outlet is higher than on the side of the inlet - the ball is pressed tightly against the valve seat and completely blocks the lumen of the pipeline.

The principle of the valve bypass

When the pump is turned on, the hydraulic pressure created by the unit presses the valve ball and closes the straight line. When the pump is turned off, the pressure in the gravitational system opens the valve and the water goes through the bypass

The disadvantage of valve bypass is its sensitivity to clean water. The ingress of pollution - flakes of scale, rust, scale - leads to its failure.

Injection bypass works on the principle of a hydraulic elevator. A pumping unit welded to the main pipeline of a large diameter is arranged on a pipeline of a smaller diameter. In this case, the inlet and outlet connections have a continuation inside the pipeline pipeline.

When the pump is turned on, a part of the flow enters the inlet diffuser, passes through the unit and accelerates.

The outlet pipe has a slight narrowing and is a nozzle through which the liquid under pressure is ejected into the main line at high speed.

Behind the cutoff of the outlet (in the direction of the coolant in the line) creates a vacuum area. Due to this, the liquid from the bypass is drawn in. A jet flying under pressure carries the environment with it, transferring kinetic energy to it.

Thus, the entire flow rushes further along the highway with acceleration. Such a directional movement of the fluid eliminates the occurrence of reverse flow.

If the pump does not work, the coolant quietly passes through the bypass in the mode of natural circulation.

[caption id = "attachment_13222" align = "alignnone" width = "430"]Schematic diagram of the operation of the injection bypass The impulse to the movement of the coolant from the main with injection bypass gives the energy of a jet of water. Such a device is not afraid of a small pollution of the coolant, because it does not have devices with precisely fitted parts (ball-saddle) [/ caption]

Purpose of the bypass pipeline

The main purpose of the bypass area is to maintain circulation in the heating line in the event of a breakdown of a connected unit or a power outage.

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Any device connected via the bypass can be disconnected from the hydraulic line by simply closing two taps - at the inlet and outlet. After that, the entire flow of coolant will go through the bypass pipe.

The device, disconnected from the main line, is quietly repairing or performing scheduled maintenance. You can completely disconnect it and replace it with a new one. You do not need to stop the system and drain the entire coolant.

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In the individual heating system bypass is used in the following cases:

  1. Insert of radiators in the one-pipe highway;
  2. Binding [link_webnavoz]circulation pump;
  3. Connection distribution manifold at the device of water heat-insulated floors;
  4. The organization of a small contour of circulation when using a solid fuel boiler.

Depending on the place of use, the bypass connection has its own characteristics.

Bypass connection of the circulation pump

Traditional piping circulating pump, where the bypass is part of the main line. It is fitted with shut-off valves to allow the entire flow of coolant through the pumping unit and eliminate recirculation.

Situation # 1 - for a radiator

Connecting radiators through the bypass is carried out only in single pipe system.

For two-pipe system and collector wiring insertion of bypass nozzles does not make sense. The heating batteries in them are connected in parallel and water of the same temperature comes directly from each one directly from the supply line.

The failure of one of the heating circuits, in the presence of shut-off valves, does not affect the performance of the rest of the system.

In a one-pipe system, due to the consistent connection of heat-transfer elements, water is cooled as it passes through the circuit. The higher the heat dissipation of the battery, the colder the liquid will be at the outlet.

If bypasses are not provided for in the single-pipe wiring, the first radiator will take the maximum amount of heat and will be too hot, and slightly warm water will flow through the latter.

The supply and return connection by a jumper near each battery divides the flow into two parts. One goes to the radiator and gives off thermal energy.

The second, keeping the temperature, flows along the contour and connects at the outlet with the flow from the radiator. Thus it is possible to bring a sufficient amount of thermal energy even to the last in the chain of radiators.

Bypass radiator connection

The purpose of the bypass in the single pipe heating wiring, in addition to the possibility of radiator repair, is to keep a part thermal energy in the main flow for its more uniform distribution between near and far heating instrumentation

Situation # 2 - when the pump is connected

Connecting the circulation pump through the bypass makes sense only in a system adapted for gravity flow of water.

A booster collector should be arranged, necessary slopes and sufficient pipe diameters should be observed. A circulation pump in such a line is installed to increase its efficiency.

If the heating system was originally conceived as forced, then it would not be able to function in the event of a power outage or breakdown of the pump.

The coolant will not circulate without the distillation unit. Therefore, in such a line the pump is installed without a bypass - on a straight line.

A feature of connecting a pump through a bypass is the possibility of a countercurrent in the bypass and the occurrence of a closed circulation loop around the bypass pump.

Therefore, in the bypass pipe should be installed check valves - ball valve or check valve.

When the pump is running, such equipment completely covers the lumen of the bypass pipe (valve - automatically, valve - manually). If the pump stops, the bypass opens and convection movement of the coolant occurs.

An exception is the injection bypass, the design and principle of which excludes the reverse movement of the fluid.

Examples of pump units with automatic bypass

Bypass connection of the hydraulic pump can be made independently, or purchase a ready pumping unit. Type of wiring is selected depending on the availability of free space

Situation # 3 - when installing underfloor heating

The bypass line when connecting underfloor heating is part of the mixing unit. Therefore, it is used constantly, and without it, floor heating will not function normally.

The water in the supply line can reach 80 ° C, and in the contour of a heated floor it should not exceed 45 ° C. To prepare the coolant, a mixing unit with a three-way valve is used, which passes only the required amount of hot water.

The rest of the flow goes through the bypass, mixes with the chilled water leaving the collector and goes further along the main line to the boiler.

Bypass on the collector of water heated floor

A three-way valve installed in front of the entrance to the collector, passes as much coolant as is necessary to heat the water in the heated floors to a comfortable temperature. Excess hot fluid goes back to the highway bypass

Situation # 4 - in the highway with a solid fuel boiler

With the help of a bypass in the strapping of a solid fuel boiler, a small coolant circuit is formed. The bypass is connected to the supply pipeline with the maximum heated coolant on the one hand, and to the three-way valve installed on the return with the other.

The valve mixes the cooled water coming from the heat supply circuits with the hot coolant from the bypass. Liquid is passed to the boiler, the temperature of which is not lower than 50 ° C.

Such piping is necessary when using a solid fuel boiler, as condensate forms on the steel walls of the furnace when cold water enters the boiler. This leads to corrosion and rapid failure of the heating unit.

Strapping solid fuel boiler

For the operation of a solid fuel boiler form a small circle of circulation. Bypass in this case plays a key role.

Through the bypass bypass section, hot water flows into the mixing valve to heat the liquid coming from the system to a temperature that prevents the formation of condensate and corrosion on the walls of the boiler

Situation # 5 - when installing bypass pipes

Installing a bypass of different types in the heating system has its own characteristics.

When connecting radiators:

  • The diameter of the bypass pipe is selected to be smaller than the main pipeline;
  • The jumper should be installed as close as possible to the radiator;
  • It is forbidden to put a valve on the bypass in apartment buildings.

The installation of the radiator bypass can be carried out both when installing a new heating system and when upgrading an existing one. To do this, prepared pipes of appropriate diameters, two tees and valves.

At the inlet set one of the options devices:

  • ball valvewhich does not create resistance and allows to pass all passing stream;
  • valve - for manual adjustment of the volume of coolant;
  • combination of ball valve and automatic thermostat - The amount of water passing to the radiator is regulated without human intervention.

At the outlet set ball or shut-off valve.

Elements are interconnected by welding or thread. In any case, it is necessary to ensure the complete tightness of the joints, after the assembly, to carry out a test and eliminate leakage.

Pipe diameters with radiator bypass connection

The radiator warms up most productively with the following combination: the diameter of the radiator nozzles is one size smaller than the main line and the bypass diameter is smaller than the nozzles. The narrowing of the inlet sections increases the hydraulic pressure and contributes to a more complete warm-up of the heat transfer device

When a pump is connected, the bypass is most often part of the main line. Since it ensures the flow of coolant in the mode of natural circulation, in no case can its internal diameter be narrowed.

The pump is mounted on a bypass pipe, the diameter of which may be less than or equal to the diameter of the main line. Subtleties correct installation of a circulation pump discussed in our other article.

For installation, it is easier to purchase a ready-made pump unit of the required size and configuration. This will ensure the correct position of all the elements and the reliability of the connections.

However, the independent production of the isolation of the pumping unit is not difficult if you follow some rules.

The pump should be oriented so that the impeller axis is horizontal and the terminal box cover is facing upwards.

So provide free access to the terminals to which they connect the power, and prevent the ingress of liquid to them if leakage occurs.

A quality check valve or a ball valve is mounted in the bypass section in order to ensure that the flow through the pump is complete and that the liquid does not flow back along the contour.

Bypass pump connection

When arranging a self-contained pumping junction, it is important to correctly position the elements. It is convenient to use cap nuts - American. Such fittings provide tight, durable connection of elements, easy disassembly and assembly

Conclusions and useful video on the topic

Errors in the installation of a bypass radiator, which lead to poor heating of the heat emitting element:

Why it is impossible to install a stop valve on the bypass of the radiator in an apartment building:

How to assemble a bypass pipe with a pump in such a way that it is convenient to disassemble an already installed and connected product and conduct routine maintenance and repair of components:

A simple engineering solution - bypass - allows you to make the heating system more efficient and achieve a comfortable thermal regime in all rooms.

Breakdown of individual elements of the highway or a power outage will not cause major problems. The coolant will circulate through the line and the house will be warm.

You started self-installation of the bypass and want to find out something? You can ask your questions in the comments to this article.

Or do you have a positive build experience? Share it, please. Perhaps some of the home craftsmen will be able to avoid mistakes thanks to your recommendations.

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