Bypass in the heating system: what is it

If your house were a living thing, your heating system would be the heart, pumping warmth all through its veins. However, obstructions and inefficiencies can affect it just like they do any other organism. The phenomenon known as a bypass is one frequent offender in heating systems. However, what is a bypass exactly, and why is it important?

To put it simply, a bypass in a heating system is when hot water accidentally travels somewhere other than the intended path—through radiators or other heat emitters. The water almost acts as a shortcut, denying some parts of your house the necessary warmth.

Imagine this: You expect every room in your house to warm up gradually as you turn up the thermostat. But no matter how hard you try, some rooms manage to stay freezing while others get as hot as a sauna. One possible cause of this imbalance is a bypass that is removing hot water from areas that require it the most.

How then does a bypass happen? It frequently happens as a result of shoddy heating system design or installation. It can take many different forms, such as missized pipes or misaligned valves. Sometimes it’s a case of well-meaning homeowners trying to adjust their heating system on their own without fully understanding the consequences, leading to a DIY fix gone wrong.

However, the effects of a bypass go beyond just being uncomfortable. In addition to causing uneven heating throughout your house, it also increases energy costs because your heating system has to work harder to make up for the heat that is lost. Furthermore, a bypass can hasten the deterioration of your boiler and its parts, which could eventually require expensive repairs.

Luckily for most homeowners, locating and fixing a bypass is affordable. By learning the fundamentals of how your heating system works and identifying the warning signs of a bypass, you can take preventative measures to bring efficiency and balance back to the heating system in your house. We’ll go into more detail about bypasses’ causes, consequences, and—most importantly—effective ways to address them in the sections that follow.

In the world of home heating, understanding the concept of a bypass in the heating system is crucial. Essentially, a bypass is a small pipe that connects the supply and return lines of a hydronic heating system. It serves as a safety valve, allowing some water to flow directly from the supply to the return without passing through the radiators. This helps regulate the pressure in the system and ensures proper circulation, especially when some radiators are closed or blocked. By maintaining a balanced flow of hot water, a bypass prevents issues like overheating, noisy pipes, and pump damage. Overall, knowing how to properly install and maintain a bypass can significantly improve the efficiency and longevity of your home heating system, ultimately saving you money and keeping your home cozy throughout the colder months.

What, in principle, is any bypass?

A novice user might initially believe that the word "Bypass" refers to some sort of intricate installation or operating principle that is hard to remove without the right tools. Actually, everything is a lot simpler. I just could not believe that this is the name, even though I’m sure everyone saw this exact Bypass with their own eyes.

The name itself gives away the hint. Any online translator you try to enter the word "bypass" will yield a number of translations with the same meaning, such as "bypass", "bypass", "overwhelm", "go bypass," and so forth.

A bypass is merely a pipe that crosses another pipe, opening the possibility of a different direction for fluid movement.

In plumbing, a bypass is commonly referred to as a pipe-cross, which is a cut made into a device’s path. It opens up the possibility of a different direction of fluid flow (coolant in heating systems or regular water in tap systems). The bypass can function in one of three ways: it can be manually operated by cranes or valves mounted on it, or it can have a valve or other device that automatically switches the fluid flow when needed. Uncontrollable mode involves the bypass being open all the time.

Heating systems can have bypasses installed in a number of locations. Usually, this is a heating radiator strapping. He is conventionally utilized in the circulation pump node of autonomous home systems. The bypass becomes a part of the mixing unit in the complex of collector-type heating systems. Lastly, it’s employed when solid fuel boilers are strapped. Examine each of these situations in greater detail.

Avoid paying the costs of heating systems.

Bypass for heating radiators

Bypass in the outflow of heating radiator

The need for bypass on the radiator, the principle of its action

To understand the significance of bypass, let’s go back to the typical layout of the heating system in apartment buildings.

A single-pipe heating system has been in use and is still in use today in many high-rise buildings of the old building because it simplified the design and decreased the installation costs. The building’s heat station, located on the elevator node, has two collectors: feed and "return." A pipe-state begins with the feeding up method, and from there, heating radiators are "strung" in succession beginning on the last floor (option A: with the upper feed). Option B: with the lower presentation is a similar scheme where the riser also catches the sequential radiators all the way to the top point.

The sequential positioning of heating radiators without bypas is an extremely risky scheme.

Consider what would happen if at least one radiator suddenly failed, regardless of the riser or the floor on which it occurred. You will need to disassemble it in order to replace the battery. And this means that this incredibly stable "chain" needs to be broken automatically. Complete inoperation of the riser (or even two, as in the example on the right) occurs.

And here we have it again: the same plan enhanced by bypasses on every heat transfer component.

Additionally, each radiator’s bypass system ensures that it will function even in the event of an accident.

It is clear that the functioning of the system as a whole won’t be impacted if one of the batteries experiences an accident or if a radiator needs to be replaced with a new model during the heating season. As seen on the dash on the right, all that is required to block the heat transfer device is the installation of locking cranes, which is highly recommended. After that, repair work or total dismantling can be easily completed. The riser’s bypass will supply the coolant circulation required for each additional radiator.

The use of bypasses in the strapping of a radiator in a single-pipe heating system offers benefits beyond this. Most people are probably familiar with what happens when winter heat waves unexpectedly arrive, but the centralized heat supply system is not designed to adapt quickly to these kinds of changes. The result is that the rooms are extremely hot, which is worse than having just a little bit of heat. Open wind-out windows in the winter are drafts that bring no benefits. Therefore, having the ability to change the heating radiators’ level is recommended.

Such an opportunity is provided by the bypass one-pipe system. It is sufficient to install a straight thermostatic valve at the battery entrance in place of a shut-off crane, or even in conjunction with it, and to quantitatively adjust the heating level as needed. It involves varying the amount of coolant that flows through the radiator in a given amount of time. Simply put, the coolant that isn’t used to reach the required degree of heating is "dumped" into the general circulation system via the bypass.

Binding radiator with direct thermostatic crane and bypass

It appears so, but what keeps such a thermostatic crane or valve from being installed without a bypass? Absolutely, there will be thermoregulation; however, since this type of crane relies on a reduction in the overall volume of coolant passing through the radiator, all batteries linked to this riser will be impacted. It’s also unlikely that the neighbors will approve of it.

In other words, the bypass becomes an essential part of the radiator strapping in a single-pipe heating system of an apartment building.

The owners of private homes are undoubtedly free to "experiment" as they see fit in their autonomous systems. Nevertheless, installing a bypass offers them numerous benefits, including the previously mentioned ability to maintain any part of the system and a more even distribution of heat throughout the building. It is possible to disconnect a room entirely if needed or desired; this won’t have an impact on the heating system’s overall performance.

The same riser system or horizontal wiring at each level, as in a one-story building, can be used in a private home with two or more stories. The essential components remain the same: a jumper is still installed between each radiator’s input and output in a single-pipe system with horizontal wiring.

The possibility of wiring horizontal pipes with a radiator connected

Leningradka is one of the "classic" systems, combining ease of installation and efficiency with enough adaptability. Every heating battery has a "bypass node" built into it, which operates on certain predetermined principles. Furthermore, the horizontal pipe of the heating circuit itself frequently serves as the same kind of jumper that is needed between the radiator’s release and entrance.

Leningradka system: every heating radiator in the system is fully independent, even though it only has one pipe.

The Leningrad system is still widely used by private developers because of its ease of use and many indisputable benefits.

How should the "Leningrad" heating system be set up? For such a system, there is only one basic diagram, but there are various implementations that could be done. A comprehensive guide is available on our website especially for people who want to set up a "Leningradka" heating system in their house.

Video: The key role of bypasses in the strapping of radiators of a single -pipe heating system

Baypas installation in a heating radiator strapping

Installing bypas on the heating radiator should be handled by owners who have already dealt with the installation of plumbing pipes and the necessary reinforcement. No particular challenges should arise if one is skilled in threaded joint assembly, node fitting, and polymer pipe welding (rations).

The most important thing is to abide by the following installation guidelines:

• There should not be any locking elements between the main pipe of the circuit and bypass. This is how the probability of even random overlap of normal circulation of the coolant through the entire contour is excluded.

Estimated bypass installation plan for a single-pipe heating system on a vertical riser

• If the bypass is mounted on a vertical riser, then it should be placed, if possible, at the maximum distance from the riser and at the same time – as close to the heating radiator as possible. Of course, at the same time, free space should be thought out in advance to install shut -off (and adjusting, if planned) taps at the entrance and exit from the battery.
• The diameter of the pipes from which the bypass node of the radiator is assembled is always important. The “classic” scheme is as follows: on a branching tee, a pipe that goes to the heating radiator has a diameter of one size less than the diameter of the riser, and the bypass itself is two sizes smaller than.

An example is shown in the figure: the circuit (riser) is made of a 1 inch pipe, therefore, the radiator pipe should be ¾ inch, and the pipe from which the bypass is made – ½ inch. With such proportions, the correct operation of the radiator will be ensured without any additional intervention – according to the laws of hydraulics, the flow of the coolant will be divided into the main one, following the radiator and causing it to heating, and the straight line going through the bypass. By this, by the way, the most optimal expenditure of thermal energy is achieved. The heat is practically not wasted on a direct piece of byipas, thereby compensating for the flows of the losses that have gone to heating this room when reverse mixing.

The ideal diameter ratio for a single-pipe heating system’s horizontal contour position

The shape of the ratio is typically a little different when it is in the horizontal position. The main tube itself assumes the role of Bypas. It is advised, nevertheless, to narrow the space by one size between the radiator and the tee of branches. As a result, the heating battery’s tap-equipped pipework should be two sizes smaller than the main pipe.

• Is it permissible to put the valve on the bypass? It would seem that he begs – with its help you can also adjust the number of coolant passing through the radiator. For example, with heat failure, such a measure can give a certain effect – closing the crane, the owners redirect the entire stream through the battery.

The question is ambiguous. If we are talking about a riser of a one -pipe heating system in an apartment building, then the installation of a crane will become a gross violation. The overlap of bypasses in one or several apartments leads to the impassion of the general scheme of heat distribution, that is, the effect of increasing heating in one place is achieved exclusively at the expense of other residents of the house. If complaints about the quality of utilities and the verification will be identified unauthorized taps on bypasses, it does not matter from their closed or open position at the time of the revision, then there is no doubt that these owners will dump the responsibility for everything. It is clear that it will be very difficult to make excuses to the neighbors, and so you can make a bunch of enemies for yourself. This is not counting the possible measures of the administrative plan.

Installing a locking valve or adjusting crane on the radiator bypass in the riser of an apartment building inconsistently will be viewed as a flagrant violation of the apartment owners’ rights.

However, these adjusting cranes are frequently used in the autonomous system of a private home. In this instance, it is not even necessary to strictly adhere to the diameter proportions of the bypass pipes because everything can be manually balanced, allowing the crane to either widen or narrow the coolant passage. This is a fairly common occurrence in the same "Leningradka" that raises the system’s overall flexibility.

Each segment of the main pipe, which functions as a bypas on a specific radiator, has an adjusting crane installed on it.

In the illustration, an example is provided. In this instance, the radiators are connected to the contour via standard ball valves (pos. 1), which merely serve as shut-off valves in the event that the battery is completely disconnected. Additionally, a needle crane that is mounted on the main pipe segment between the tees and serves as a bypass during this connection already performs the precise balancing. Nevertheless, this does not impede the thermostatic valve or valve that is additionally installed right at the battery entrance. Everything, to put it simply, is under the owners’ control.

You don’t need many specifics to install a bypass. Generally speaking, everything is restricted to two bouncers, two tees with a snow diameter of outputs, two ball valves, multiple pipe segments, couplings, or skiing for final assembly if there isn’t a complex configuration.

Polypropylene, metal-plastic, or metal pipes can all be used to create this kind of node. A few illustrations are provided below; those familiar with the subject matter should find them easy to understand. Since they lack the necessary skills for such an assembly, people are reluctant to take on independent work; instead, they should use it as a guide to have a specialist invited to verify that the work is correct. Regretfully, a number of glaringly inexperienced profiles that were merely looking for quick and simple money emerged among them.

The radiator strapping assembly assembly assembly diagram with polypropylene pipe bypass

The diagram shows that:

Pos. 1: A riser pipe coming from the coolant side. Consequently, pos. 2 is the identical riser, but it is now coming from the return side.

Fittings were used to switch from the metal pipe’s threaded section to polypropylene (pos. 3).

Pos. 4.1: Two segments of a 32 mm-diameter polypropylene pipe (in this and all other areas, reinforced pipe is required for hot water).

Two segments in position 4.2 have an external diameter of 25 mm.

The reason why adapters might be needed for the desired diameter is because these segments are welded into two tees (poses. 5).

Pos. 6-The bypass itself, consisting of a 20 mm-diameter reinforced pipe segment.

Pos. 7: Fittings for the cranes’ switch to the metal threaded section.

Pos. 8: A thermostatic straight valve (or valve) is installed in the radiator at the entrance. If the heating level doesn’t need to be adjusted, you can use a regular ball valve.

Ball shuttle valve (pos. 9) accessible from the radiator’s side.

The best way to handle the radiator is to use a coupling connection with a sideline nut, or a "American," which will make it easy and quick to install or disassemble (pos. 10). They are frequently already a part of the collection of shut-off regulating devices.

Pos. 11: radiator for heating.

Different pipe diameters are possible depending on the heating riser’s specifications. However, as stated in the text above, it is advised to observe the ratio.

Drawing of the battery’s binding knot assembly made of metal and plastic pipes

The binding node assembly scheme with the bypass using metal-plastic pipes is only utilized when specific press fittings are used rather than welding. The list of details is fairly similar otherwise. The diagram indicates that a thermostatic regulation device or a shut-off valve can be installed at the radiator’s entrance, depending on preference.

It all depends on the master’s abilities and preferences if the node assembly is done using the VGP’s steel pipes. This design can be welded, but only if the radiators themselves have a detachable connection (drives or, more conveniently, "American" nuts). This node can be assembled entirely on threaded joints, as demonstrated, for instance, in the illustration below:

The threaded connection technology is used throughout the entire strapping node, including the bypass itself.

In this instance, the bypass itself, with its upper and lower horizontal pipes already welded, is available for purchase as a completed item. These assemblies are available for purchase in specialty stores and are made for radiators with standard interdest distances.

Two tees and a pipe segment can be assembled to create a metal bypass. However, a completed piece with boiled pipes and pipe threads already chopped on them is available for purchase.

Information about how to select an electric boat for heating may be of interest to you.

Is the bypass on the two-pipe heating system necessary? This is another query regarding the strapping of radiators.

No, he is no longer involved in any way. Since each radiator "relies" on the feed pipe and the "return," they are all totally independent. With a parallel connection like this, the blocked battery can be turned off or even taken apart entirely at any time without affecting how the system functions as a whole.

Although the two-pipe system is more costly and challenging to install, it offers more benefits. It is becoming more and more common in multi-story buildings, so if your apartment has one of these systems, you won’t need to worry about bypas.

It’s true that you have to confirm that the system has two pipes. The system is still made up of a single pipe, despite the appearance of a second pipe that serves merely as a riser to supply the coolant at an upper level. In this instance, a bypass is needed because the radiator is connected sequentially to a single pipe.

This system does not have two pipes, so do not be misled. All that needs to be done is transport the coolant from above through one pipe; bypass is not necessary.

The radiator in a two-pipe system must be connected to the submission and "return" risers, which are two separate risers. In this case, bypass will not be relevant.

The absence of a bypass is one illustration of a two-pipe system.

Bypass in the node of the circulation pump

To demonstrate that it is most likely not required for a private home’s autonomous heating system, which operates on the principle of forced coolant circulation. Even though the pump itself uses energy, the installation of the pump quickly pays for itself in terms of the best possible heat distribution in the rooms and operational efficiency. Even owners of systems that were originally intended for natural, gravitational circulation do not object to the additional installation of the pump unit at this time.

The issue, however, is that there are several places where there isn’t a power outage in the electrical supply. As a result, the heating system that is connected to the circulation pump starts to depend on energy randomly. It is advisable to consider an alternate source of electricity in this situation, such as a generator or a reliable power source. However, this will only be beneficial temporarily. Therefore, the heating system must be designed to be able to switch to operating on the principle of natural circulation in such dire circumstances. And the pump unit’s bypass is helpful in this regard.

Switching from forced to natural circulation is possible with pumping nodes with bypass, which operate differently in practice but exactly the same in principle.

Such a node can operate in manual mode, whereby the hosts just need to turn on and off the taps to reroute the coolant flow along the main pipe rather than through the bypass with the pump in the event of a power outage. Other assemblies employ valve devices, which automatically redirect the flow in those assemblies. An injector diagram is an additional choice that you have if you don’t need a crane or a valve. However, it isn’t highly recommended, so you should stick with the "classic."

We won’t stop at the pump node with bypass in this publication. Not at all, considering how unimportant this question is. On the other hand, a different publication is devoted to the issues involved in selecting and installing the circulation pump correctly, from the necessary calculations to the detailed instructions for self-installation.

Pump that circulates the heated system. It is clear why forced circulation of coolant along the heating contour is beneficial. Neither the pump itself nor its installation are particularly expensive. Therefore, please take a moment to read the special publication on our portal that will guide you through the process of installing a circulation pump yourself and choosing the right one.

Costs associated with various circulation pump types

circulation pump

Component	Description
Bypass Valve	A valve installed in the heating system that diverts some of the hot water flow around the main heating circuit.
Purpose	Allows for better control of the water flow through the system, ensuring proper distribution of heat and preventing overheating in certain areas.

Maintaining effective and efficient heating in your home requires that you understand what a bypass in the heating system is. In essence, a bypass is a plumbing element that permits water to circumvent specific heating system components, guaranteeing appropriate circulation and averting overheating. Bypasses contribute to the maintenance of constant temperatures throughout your house by controlling the hot water flow.

Controlling the pressure inside the heating system is one of the bypass’s main functions. The efficiency of the boiler can be negatively impacted by a significant drop in pressure when all radiators are fully open. Your heating system will run smoothly and effectively thanks to the bypass, which helps maintain the ideal pressure by rerouting part of the hot water away from the radiators.

Bypasses are also essential for safeguarding your boiler from harm. Excessive strain on boiler components can result in malfunctions or breakdowns when the temperature of the water returning to the boiler is too high. The bypass lowers the risk of damage and increases the lifespan of your heating system by allowing some of the hot water to return to the boiler at a lower temperature.

Your heating system’s bypass must be configured and maintained correctly to maximize energy efficiency and reduce heating expenses. A well-thought-out bypass system can assist in regulating the hot water flow, guaranteeing that every room in your house has enough heat without using extra energy. Frequent bypass maintenance and inspection can help your heating system operate at peak efficiency and ultimately save you money. This includes checking for leaks and modifying flow rates as necessary.

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