To everyone who has even a little experience with engineering networks, you are probably familiar with the term “bypass”. In simple words, This bypass line, along which water can flow due to various circumstances. In the article we will consider these circumstances and understand what role the bypass plays in the heating and water supply system. We will also show you how to install it correctly with your own hands if necessary.
Bypass functions in the heating system
Let us clarify that a bypass is a pipeline designed to bypass water flow a certain area highways where any equipment is installed. In heating circuits it can be found in two places:
- in single-pipe systems as a jumper on radiators;
- on the water distribution manifold heated floors.
As you know, in a one-pipe heating system, the heat transfer of the first battery affects the operation of the next one, and so on. This applies to both vertical and horizontal scheme. If a bypass is not installed in the heating system, the radiators will be switched on in series. As a result, the first one will select maximum amount heat, the second is all that remains, and the third will receive only the cooled coolant.
To prevent this from happening, the supply and return near each battery are connected by a jumper, whose task is to direct part of the coolant bypassing the radiator. In this case, the principle of operation of the bypass is to transfer the same part of the heat to near and far heating devices and reduce their dependence on each other. How this is implemented can be seen in the figure:
Important. In the shown vertical system the bypass device is designed so that the diameter of the pipe is smaller than the main line and slightly offset from its axis to the side. The goal is to prevent the coolant from passing in a straight line under the influence of gravity, past the radiator. In a horizontal system, the main pipe itself is a bypass, while it does not shift anywhere and remains the same flow area everywhere.
In a heating system, a bypass is needed to distribute heat evenly across the radiators, as well as to perform their repair or maintenance. If for some reason you need to disconnect and remove heating device, then it is enough to simply turn off the 2 taps installed at the inlet and outlet of the coolant. Then the water will follow a bypass path through the jumper.
But the heating bypass on the water heated floor manifold plays a different role. Here the bypass line is part of a mixing unit with a three-way valve. The task of the unit is to prepare the coolant at the required temperature for supply to the heating circuits of underfloor heating. Indeed, in these circuits the water temperature does not exceed 45 ºС, while in the supply line it can be 80 ºС.
In normal operation, the three-way valve allows hot water from system to warm floor in limited quantities. The rest of the coolant passes through this automatic bypass and mixes with cold water from the collector and returns back to the boiler. Since the temperature difference in the main and collector is significant, the bypass line is used constantly. It turns out that without it normal functioning underfloor heating impossible.
Bypass in the boiler room
In boiler piping schemes, a bypass line is also necessary in 2 cases:
- as a bypass for a circulation pump;
- for organizing a small circulation circuit for a solid fuel boiler.
A pump installed on a bypass pipeline is found in heating systems quite often, sometimes even without special need. The fact is that a one-pipe or two-pipe heating system, originally designed with forced circulation, will never be able to function when the pump is turned off. It does not have large slopes and increased pipe diameters for this. But a bypass for the pump is precisely what is needed so that water can flow in a straight line while the pumping device is not working.
Hence the conclusion: when connecting to a boiler a system designed for forced circulation, there is no need to install the pump on the bypass. Disabling and removing the unit will in any case stop the movement of the coolant, so the pump is installed in a straight line.
Another thing is a system adapted to the natural movement of water. It often happens that in order to increase efficiency, a pump is not simply built into it, but a bypass system is installed with check valve on a straight line. This allows you to automatically switch to power in the event of a power outage. natural circulation, which is reflected in the diagram:
While the pump is running, it presses the valve with its pressure reverse side and does not allow the flow to flow in a straight line. As soon as you turn off the power or turn off one of the taps, the pressure will disappear and the bypass valve will open a direct path for the coolant, convective movement of water will be restored. You can safely remove the pump or clean the sump; this will not disrupt the operation of the system, it will simply switch to a different mode.
Well, the last place to use the bypass is the small circulation circuit of a solid fuel boiler with mixing unit. Here is a jumper connected to three way valve, allows the heat generator to warm up to a temperature of 50 ºС in order to avoid exposure to low temperature corrosion on the steel walls of the firebox. In this case, the bypass circuit looks like this:
The principle of operation is simple: the valve does not allow entry into the boiler cold water from the system until the coolant circulating through the bypass line reaches the required temperature. Then the valve opens and lets cold water into the circuit, mixing it with hot water. Then condensation does not form on the walls of the firebox and corrosion does not occur.
Sometimes a bypass is still needed in the water supply system. For example, to remove a heated towel rail in the bathroom for repair, cleaning or replacement. Since it is connected to the DHW riser, then apartment building dismantling it will create a lot of inconvenience. It’s easier to foresee this in advance and install a jumper with a tap when installing the heater.
How to install the bypass correctly
The distribution unit for underfloor heating also includes a bypass line, but this is a topic for another discussion. As for jumpers on a one-pipe system, their installation is very simple and is carried out during the installation of the system, since without them the latter will not work correctly. It is not much more difficult to install a bypass line with your own hands circulation pump. It is enough to have a regular set of tools and study the diagram:
Advice. In order not to collect all the parts separately, you can buy a ready-made assembly, shown in the figure below:
Installing a bypass for a heated towel rail is also not difficult. For connections you can take metal-plastic pipes, and also purchase taps, tees and bends. Perform assembly in accordance with the diagram:
Conclusion
It turns out that a simple piece of pipe, which is a bypass line, can play an important role in many cases. Here it ensures the operation of the system, there it helps distribute heat, and sometimes protects the equipment. In all of the above cases, you cannot do without a bypass.
Via bypass in the heating system modern house mount it all key elements. This simple engineering solution facilitates the maintenance and repair of equipment connected to the main line. It also increases the efficiency and economy of heating, which is not bad at all, isn’t it?
Do you want to add a bypass to your heating system, but don’t know how to do it correctly? We will help you cope with the task - the article discusses the purpose of this element heating system And key points its installation.
A bypass, or bypass bypass, is a pipeline that serves to organize the flow of coolant bypassing a certain section of the heating main, or parallel to it.
Most often, some equipment is installed in this area. One end of the bypass pipe is connected to the inlet pipe, the other to the outlet pipe.
Between the bypass and the inlet of the device being bended, install shut-off valves. It allows you to completely redirect the flow of water along an alternative path, or regulate the amount of liquid entering the device.
To make it possible to completely turn off the equipment, install a tap on the outlet pipe - between the outlet of the device and the bypass.
Image gallery
Because the hydraulic pressure on the side of the outlet pipe, higher than on the side of the inlet pipe - the ball is pressed tightly against the valve seat and completely blocks the lumen of the pipeline.
Even the most minor malfunctions engineering communications can potentially develop into acute problems and, as a result, cause serious discomfort for all household members. That is why prudent owners try with all their might to prevent such inconveniences by installing in their homes various kinds auxiliary devices. One of them is a bypass, which is actively used in systems and. We will talk about it further: let’s figure out what kind of device this is, what are the principles of its operation, what are its advantages and why it is needed. And finally, we’ll tell you and show a video of how to install a bypass valve with your own hands.
Design and principle of operation
Structurally, the bypass is a jumper pipe with shut-off and control valves. His the main task– create a parallel flow of working fluid bypassing a specific device in the engineering system. In other words, the bypass creates a bypass line.
The principle of operation of the device is extremely simple: during the normal functioning of the heating or water supply system, the jumper freely allows a flow of liquid to pass through it, but as soon as this flow needs to be limited, locking element the bypass closes and the liquid begins to bypass a certain section of the system. Such blocking is possible due to the difference in diameters of the bypass itself and the supply pipe - the first is always smaller than the second.
Bypass placement Using a bypass has many advantages. Firstly, the maintenance of heating and water supply systems is significantly simplified. Secondly, when large quantities Heating batteries increase the overall efficiency of the system and reduce energy costs. Thirdly, the problem of air in pipes and batteries due to their depressurization disappears. Fourthly, it becomes possible to use the equipment even in non-standard and emergency situations. How do all these benefits become a reality? Let's find out by getting acquainted with the features of using jumpers in different engineering systems. But before that, let’s find out what modern bypasses are.
Types of bypasses
Bypasses are classified according to two criteria:
- type of shut-off valves;
- appointment.
Based on the first feature, two types of bypasses are distinguished:
Important! An automatic bypass with a valve can only be installed in those heating and water supply systems where only clean media are used - scale, scale, rust and other dirty impurities, if they get on the valve, can cause its deformation, as a result of which the locking mechanism will no longer close completely.
Based on their purpose, bypasses are divided into:
- radiator - installed on the approaches to and used to turn them off if necessary;
- pumping - mounted together with pumps and used either to change their operating mode or to completely shut down;
Features of application
Most often, bypasses are used for the following purposes:
- Maintenance of individual devices without stopping the entire system. If for some reason you need to remove equipment in the heating system or on the water supply line, for example, to repair or replace it, you should simply close the inlet and outlet valves of the working medium and then the liquid will flow through the bypass, and you can dismantle the necessary device without consequences .
Bypass in the heating system - Improving the operation of a single-pipe heating circuit. Main disadvantage single pipe system– uneven distribution of coolant: since the batteries are connected in series here, as it moves, the working fluid cools down and the last devices receive almost cold coolant. To avoid this, a bypass is installed in front of each radiator - thanks to it, a certain part of the media moves around the batteries and, as a result, reaches hot water even to a distant device.
Advice. In a similar way, you can regulate the heat transfer of radiators in two-pipe system– simply turn off the tap in the selected location, and the hot medium will move to those areas that really need heating.
- Maintaining the heating system without power supply. If the system uses an electric pump, then it is logical that if the power supply is turned off, it will stop working and stop the heating process. But the bypass will also save you in this situation: by turning off the pump supply valve and allowing the media to flow through the jumper, you can activate the natural circulation of the liquid and restore the system’s functionality.
Bypass installation
To carry out proper installation of the bypass, you must take into account following rules and nuances:
- the diameter of the jumper must be narrower than the diameter of the pipe to which it is connected, otherwise the carrier simply will not enter the supply device;
- the bypass should be as far as possible from the riser - it is located as close as possible to the device that it will serve;
- the jumper should be positioned horizontally to avoid the effect of airing;
- Before starting installation, you need to drain all media from the system.
The installation itself can be done in two ways.
Bypass installation The first is through welding. First, remove the device that will close the bypass - most often it is a battery, so we will consider the process using its example. Then at the most convenient location make holes in the supply pipe according to the diameter of the jumper, insert it tightly and weld it. Next, install shut-off valves on the thread where the radiator used to be. Finally, place the battery in a new place, connect it to the system and fix it with brackets on the wall.
The second is using couplings. Here also, first remove the device. Then screw the bypass onto the inlet pipe using factory couplings, and install shut-off valves on the opposite edges. Next, move the fastenings of the removed device, place it in a new place, connect and secure with brackets.
As you can see, at first glance, a simple piece of pipe that acts as a bypass jumper can help in many situations. The bypass successfully covers a wide variety of needs in water supply and heating systems - from maintaining operation at critical moments to protecting equipment, so without its installation, the full functioning of utilities will be very difficult.
What is bypass: video
