Why is the return line cold? Why is the bottom of the battery cold and the top hot?

I'll start by comparing two-pipe heating systems (CO) with single-pipe ones.

Single-pipe vertical CO:

We are accustomed to the most common vertical single pipe systems multi-storey buildings. Where to the touch the radiators seem to be heated evenly over their entire surface. Actually it is not. The coolant must cool in the radiator by at least a few degrees, transferring heat. By hand, by touch, a person usually cannot feel such a difference (3-5 degrees). But, if you measure the temperature of the radiator surface with a device or a thermal imager, it will not have same value over all surfaces in any CO.

In vertical single-pipe systems of high-rise buildings, the hottest one is supplied to the first radiators (according to the movement of the coolant), and the latter has already cooled down to the design value. For example, with a thermal schedule of 80/60 degrees, the first radiators come with a temperature of +80 degrees, and the last with a temperature of +60 degrees. Naturally, such a heat schedule takes place only in the most severe frosts (a cold five-day period). The thermal graph (simply a graph in the future) is the temperature of the supply and return to CO.

And so that at the same time all floors get right amount heat, the first radiators on the riser have the least sections, and the last radiators have the most. For example, the first radiators consist of 7 sections, and the last ones already have 12 sections. I note that cooling (to the design value) to the last radiators is essential for proper operation at a heat generating station (boiler room). Otherwise, the cost of heat generation (fuel consumption) increases greatly. Therefore, heat generating organizations penalize heat consumers for insufficiently cooled down.

Subjectively, when living only on one floor of a high-rise building with a single-pipe CO, it seems to us that our entire radiator is warmed up evenly in the same way. And we get used to it like correct work SO (as for granted), and we begin to think that this should be the case always and everywhere.

Two-pipe vertical CO:

Since single-pipe COs do not meet modern requirements for energy efficiency, comfort and energy saving, now more and more new houses are being built with two-pipe COs.

In two-pipe COs, the necessary cooling takes place (and should) already in each radiator on each floor. Simply put, with a thermal schedule of 80/60 degrees, each radiator comes with a temperature of +80, and it leaves already cooled down by 20 degrees, i.e. with a temperature of +60 degrees. But, let me remind you that the 80/60 schedule is issued only for the most severe frosts. In the off-season, the schedule can be 50/33. Accordingly, while top part the radiator in a two-pipe CO will have a temperature of +50, and the lower part of +33 degrees.

But the temperature of the metal at +33 degrees already seems cool to the touch. Because Humans don't have a sensory organ that can measure temperature. y. We feel only the BALANCE between the QUANTITY of heat given off and received. But not temperature. Therefore, to the touch, a piece of foam with a temperature of -10 gr. we will feel warm. And a piece of aluminum with a temperature of +33 will seem cold.

And out of habit, by analogy with the experience of living with single-pipe COs, it begins to seem to us that the radiator does not heat well if it seems cool below. We begin to "ring the bells" and call plumbers.

Unfortunately, a large percentage of plumbers have a low level of qualification and do not understand the principles of operation of two-pipe COs. Therefore, or because of the lack of conscience, in order to "cut money in an easy way", plumbers most often suggest that we replace special balancing valves on radiators with full bore Ball Valves. They even intimidate the residents by showing small holes in the balancing valves, "hanging noodles" on our ears that the radiator will not work normally through such a narrow hole.

And after throwing out a special balancing valve and installing a ball valve instead, our radiator starts working not in the 50/33 project schedule, but, for example, 50/49. Yes, the heat transfer of our radiator increased at the same time, but it increased only due to the robbing (albeit unconsciously) by us of our neighbors on mass flow. Well, the fact that it has become hot is no stranger to us, we will open the windows wide open (money on the common house heat meter down the drain), and we don’t give a damn about our neighbors, and that they began to freeze. Unfortunately, this is how many people think and act. But they do not understand that by such actions, they "launch a boomerang", which will inevitably hit them on the back of the head. And, according to a bad tradition, the general "launching of boomerangs" begins already by the rest of the residents.

I will explain why this happens robbing neighbors. In single-pipe COs, the pressure (pressure difference) between the inlet and outlet of the radiator is only a few units of Pascal (a unit of pressure). And in two-pipe CO, this pressure difference is already from 10 thousand Pascal and above. Therefore, in order to ensure the design flow through the radiator in two-pipe COs, a balancing valve with increased hydraulic resistance is installed on each radiator (and therefore with a small through hole inside). So that on all floors, there is the same flow through the radiator, for example, 7 grams / second. Moreover, on each floor, this valve is adjusted by the developer to its individual setting position ( bandwidth) calculated in the hydraulic project. The different setting position is due to the fact that the pressure difference between the supply and return risers on each floor is different.

What happens when we change the balancing valve (or even just "twist" the position of its tuning dial) to ball valve? Through our radiator, not 7 g / sec, as according to the project, but, for example, 170 g / sec, starts to flow. Moreover, the pressure difference between the supply and return risers decreases, for example, from 30,000 Pascal to 200 Pascal. As a result of the disappearance of the necessary pressure difference between the supply and return risers, for neighbors on other floors, the mass flow through the radiators does not become 7 g / s, but only, for example, 0.5 g / s. Of course, these tenants are starting to freeze.

What do these tenants do from your point of view? Correctly! They call the same plumber who changes their balancing valves to ball valves.

And what happens to the tenant who was the first to "launch the boomerang of vandalism"? Correctly! His radiators practically stop heating, despite the fact that the balancing valve has been changed to a ball valve. And why? - you ask. Because the necessary pressure difference between the supply and return risers has disappeared. And if earlier the lion's share, designed for all floors, passed through the radiator of the "first launched boomerang", now this lion's share began to pass through the radiators of other floors (which also changed the balancing valve to a ball valve), but which are located closer to the pouring lines ( bottling).

As a result, the entire riser of a vertical two-pipe CO practically stops working. Radiators (with overheating) work only on a part of the floors. But that's not the whole problem. Due to the fact that the heat schedule of the riser has become, for example, not 50/33 (for the off-season), but 50/47, it returns to the heat supply organization not cooled down enough. And for this, fines will be imposed on the HOA, the Criminal Code or the housing department. Naturally, the Criminal Code will shift these fines to the tenants, hiding them in some line of the receipt for payment of housing and communal services.

The apotheosis of collective unconscious vandalism is often the installation of individual circulation pumps on each radiator by residents. But it will be just a new round of "boomerang launches" or "pump wars".

Attempts by the Criminal Code to put things in order in the future often run into resistance from those tenants who have changed heating appliances, balancing valves were replaced with ball valves, repairs were made, and they are warm. These tenants simply do not let the employees of the Criminal Code into their apartments.

Unfortunately, even changing the setting position of the balancing valves by the residents already deregulates the system and leads it to almost inoperability. For example, I will show the setting scale of the frequently used Danfoss RA-N thermostatic radiator valve, which is located under a plastic cap or under a thermal head.

If none of the residents had touched the thermostatic valve setting, the system would have remained operational.
But with our mentality, it is very difficult for us to refrain from "experimenting". After all, each tenant will think the following: “But I’ll turn this setting! Maybe it will become warmer for me, but they won’t be able to punish me for it, because my apartment is what I want, I turn it around!”.

Often people, when moving into new apartment, feel the lack of heat, which forces them to start changing something in their heating system.

There are a number of reasons for this:

1. According to social norms, the temperature in the premises should be 20-22 degrees (GOST 30494-2011). Therefore, when designing a CO, the developer often counts on heating +20 degrees for the sake of savings (on the purchase of heating appliances). Based on this value, the heat loss of the premises is calculated. But the problem is that (especially brick) houses dry out for three to five years. Therefore, in the first years, the real heat loss of the premises is much higher than the calculated ones. And the temperature in the rooms may not even reach +20 degrees, although even +20 can be cold for most people. Comfortable average temperature (at radiator heating) in the room you need to consider +22 (+25) degrees.

2. When selling not all apartments, but only part of them, the developer, in order to save heating costs, reduces the temperature (heat schedule) of the supply. Which makes the rooms even worse heated.

3. And if you are cold, then I advise you not to change either the balancing valves from the developer, or change the settings of these valves. After all, you can increase the amount of heat you receive not by stealing from your neighbors (by the amount of mass flow of the coolant), but by more cooling in your radiators (no one will complain about this). To do this, increase the power (size) of the heaters themselves, but do not touch the balancing valves and do not change their settings. If you are able to convey this information to your neighbors immediately after the delivery of the house, this will help you keep your common house CO in working order. In connection with all of the above (to reduce the impact of vandalism of residents in relation to themselves), more and more often in high-rise buildings they begin to use not vertical two-pipe CO, but horizontal ones. Moreover, heating risers are placed on landings(hallah). AT distribution cabinets in the halls at the same time set automatic regulators pressure drop at the entrance to each apartment. Then, if a tenant of an apartment voluntarily or unwittingly commits vandal changes to the CO, then this will not have a negative impact on other apartments and floors. Horizontal two-pipe COs allow you to install full-fledged apartment heat meters.

Also, horizontal two-pipe CO is increasingly being used due to the possibility of using polymer pipes, and according to the requirements of the new legislation on individual accounting heat consumption.

But, unfortunately, one often sees in the photos sent by members of the forum, the replacement by the developer of automatic pressure drop regulators with a cheap balancing valve. This drastically reduces the vandal resistance of the entire house system or a separate riser, despite the use of a horizontal two-pipe CO scheme.

Next, I will describe the situation that often occurs in two-pipe COs in the so-called "Stalinka", houses built in the 1930s-1950s.

For example, consider a scheme for such houses. Two-pipe associated system with top filling (from the attic).

The circulation rings of such a system could not be balanced well at that time, due to the lack of balancing fittings and other reasons. And the problem of unbalance was solved by increasing the mass flow. Those. a sufficient amount was pumped through the "narrowest" rings, and in the remaining rings there was some overheating.

Now, as far as I understand, heat supply organizations(TSO) begin to gradually bring the norms of supplied heat to the standards. Yes, and management companies (UK) are trying to save. Therefore, the mass flow is reduced, and people begin to feel a lack of heat in the "narrow" risers.

The only way out in this situation is a more correct redistribution between the risers. And for this, the risers need to be balanced with each other. Which should be carried out by balancing valves (valves), which must be installed on the return pipes of the risers. On the above hydraulic scheme, as an example, balancing valves VALTEC, vT.054, DN20 are used (valves of other brands can also be used).

If there are no radiator thermal valves with thermal heads (thermoelements) on the radiators, i.e. in a static heating system, the shown manual balancing valves, type VALTEC, vT.054, DN20, can also be used.

In modern two-pipe systems, in the presence of radiator thermal valves on radiators, on risers, automatic regulators are used to maintain a given pressure drop.

The heating system is complex structure , consisting of several elements combined in one circuit and is put into operation by means of a chain reaction.

But it happens that the system crashes and the water in the batteries becomes cold. The reason for this may be problems with the return.

What is a return flow in a heating system?

The return line is coolant located inside the heating system. During his work, he passes through all heating devices and gives them warmth. Then, already cooled, the coolant returns to the cauldron, where it is heated and starts a new cycle.

Photo 1. Heating scheme with a circulation pump and an expansion tank. The arrows show the movement of the coolant.

Acts as a heat carrier as a conventional water, and antifreeze. It starts up either naturally(under the influence of gravity), or forcibly(using a pump).

Causes of return problems in batteries of a private or apartment building

There are several reasons why the return line is not warm enough or even cold at all. Common problems are:

• insufficient pressure water in the system;
• small pipe section through which the coolant passes;
• incorrect installation;
• air pollution or pollution systems.

If a problem with cold return arose in the apartment, the first thing you should pay attention to is pressure. This is especially true for premises. on the upper floors. The fact is that the principle of the return is to quickly and continuous flow of liquid by system. And if her speed drops, then the coolant will not have time to push out cold water and the batteries do not heat up.

Another reason for the failure of the return flow is pollution of the heating circuit. Usually, major cleaning systems in high-rise buildings not done often. Sediment, which accumulates over time on the walls of the pipes, prevents the passage of fluid.

main reason interruptions in the operation of the heating system in a private house - incorrect installation. Most often this happens when the installation is carried out without the participation of specialists. Being incompetent in this matter, it is quite easy to mix up the supply and return pipes, or choose pipes of the wrong size.

Both in an apartment and in a private house, the problem of a malfunction of the heating system can be associated with insufficient speed water supply or airiness. In a similar way, the work of the return is affected by the contamination of the pipes.

Troubleshooting methods. Why is cleaning necessary?

To understand exactly how to solve the problem, you first need to set its source. If the batteries become cold due to insufficiently fast water circulation, in this case the installation of a special pump. It will regularly push water into the circuit under a certain pressure, thereby not allowing the system to stop or slow down.

Photo 2. Marking the Grundfos circulation pump allows you to choose the most suitable one and install it correctly.

If the cause is clogged pipes, then they just need to clean up. You can do this in several ways:

• using water-pulsing mixture;
• with help biological products;
• through pneumohydraulic shock.

Important! Such a cleaning regularly to prevent new problems from appearing.

In the event of a malfunction due to improper installation of the equipment, contact the master. A qualified specialist will certainly understand the problem and fix all the problems. In addition, he will give good advice and recommendations care and maintenance of the system.

Useful video

Check out the video for one of the possible problems with return line - battery pollution.

What problems arise in the apartment due to the cold return

Violation in the work of the return line entails certain problems and troubles.

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I have heating with a boiler "Zhytomyr-m" AOGV 7. The column is separate. The problem is that the batteries are hot on top and a little warm on the bottom. Heating has been done for a long time, about 12 years. I didn’t live here before, but now I turned on the heating and I think it should be like that? What could be the reason? What needs to be done to keep the entire battery hot?

Well, it's normal for them to be colder at the bottom than at the top.

In principle, the temperature of the radiators should not be important to you, the main thing is the temperature in the room.

So if your room is cold, then the radiator will be much hotter from the top than from the bottom.

1) high heat loss of the room (insulate windows, doors, walls, close the attic window to the street. In general, we reduce heat loss)

2) low speed of the coolant in the system (that is, the radiator proved to us that it can efficiently give off heat, but it does not receive enough heat per unit time, but the radiated is not enough to heat the room ..) (horizontal sections of the pipeline may be air-filled and accordingly changed pipe diameter, a it means that less coolant per minute gets into the radiator)

It is possible to increase the coolant speed by installing an additional pump.

Yes, if the "open" gravitational system, then periodically fresh water is added to it,

it is possible that the scale has reduced the diameters

But first I would look for sources of heat loss.))

as in this case, the roof is not just hot well))

The batteries are slightly warm at the bottom, but hot at the top, what should I do?

Well, it's normal for them to be colder at the bottom than at the top. In principle, the temperature of the radiators should not be important to you, the main thing is the temperature in the room. So if your room is cold...

In a radiator, the top is hot, the bottom is cold. What to do?

If the top of the heating radiator is hot and the bottom is cold, then this indicates that it is not functioning correctly. In this case, it is necessary to look at the entire heating system and, of course, the radiator itself. Let's see what could be the problem here.

Usually such a problem occurs if any work on the heating system was performed, including when changing the radiator. There may be two problems here. Either an air lock in the heating radiator, or the taps on the heating radiator are clogged. The reasons may be different, including incorrect start-up of the heating system or heating radiator.

Now let's figure out how to fix this defect. There are two options. Let's start simple. As mentioned earlier, the reason for this operation of the heating radiator in 99% of cases is an air lock. In order to remove it according to the first method, a Mayevsky crane or a bleeder must be on the battery. It is installed in place of the top plug.

What should be done? It is necessary to block the flow to the heating radiator - this is the upper pipe. Leave the return open. Next, open the bleeder and wait until all the air is out of the battery. Then close the bleeder and open the feed. Often such not cunning manipulation helps.

What to do if there is no drain in the heating radiator or the previous method does not work? For apartment buildings with central system heating the answer is unequivocal to call locksmiths. For those who have individual system heating, the procedure is as follows.

First, you need to turn off the feed. Open the bleeder at the top of the heating system and return pressure to squeeze all the air out of the system. If we are talking about dropping air from one riser, then you can turn off the supply only on it. But at the same time, there must be a downhill on this riser.

The bottom of the radiator is cold

If the lower part of the heating radiator has ceased to heat up, and the top is hot, then this indicates a certain malfunction in the operation of the device. Let's figure out what

The heating radiator is hot on top and cold on the bottom - how to fix the situation?

Very often, residents of private houses and apartments ask themselves the question: “Why are the batteries hot on top and cold below?”. Finding an unambiguous answer is quite difficult, because there can be several reasons for the appearance of such a problem at once. We propose to understand the situation in detail.

Batteries are an integral element of the home heating system. It depends on their serviceability how warm it will be in the rooms. At correct connection and proper operation, radiators are able to effectively heat the air in large rooms and maintain comfortable temperature over a long period. However, what to do if the top part of the radiator warms up well, but the bottom remains cold? First of all, you need to understand why this is happening.

The bottom of the batteries gets hotter

We note right away that most battery models are designed in such a way that during operation their lower part heats up a little worse. This is due to the high degree of heat transfer - during the stay in the radiator, the water has time to cool down a little before it starts to flow out of the batteries. As a result of this principle, the upper part of the appliance will always be hotter. Therefore, there is no need to worry if, during the operation of the heating elements, their surface is not heated completely evenly.

Worse, if you touch the device and notice a large temperature difference. This directly indicates that the radiator was not connected correctly, or the liquid in it circulates at insufficient speed. In the first case, the master, most likely, mixed up the pipes for the outflow and supply of water. Many property owners face this situation. The reason is the lack of qualifications of the called master or an attempt to connect the radiator with your own hands. In the second case, the bottom of the radiator is cold due to the low flow rate of water inside it. This may allow the liquid to cool completely before flowing out of the element.

By connecting the radiators incorrectly, apartment owners run the risk of being left without efficient heating in residential premises. Such a gross mistake, in most cases, is made by self-taught people. Having mixed up, they connect the pipe for the outflow of water upwards, and the channel for supplying liquid to the lower pipe. As a result, a lot of problems arise:

• water circulation is completely changed;
• the efficiency of the radiator is significantly reduced;
• the process of outflow of water changes;
• increases the risk of corrosion at the top of the radiator.

In an incorrectly connected element, the liquid enters through the lower nozzle, flows in a circle and exits. Thus, not all sections of the radiator are heated, which is why its efficiency decreases significantly. The connection in the upper part does not make it possible to drain water from inside the device, because there is no such high pressure. When ingested, water tries to immediately rise to the top of the element. This is due to the fact that hot water the density is slightly greater than that of the cold one. Because of this, the coolant travels the shortest path, skipping the radiator sections.

When properly connected, fluid enters from the top of the instrument and flows along the top manifold. Due to the low pressure in the radiator, the coolant enters the columns and flows into its lower part. In this case, the element works effectively. To solve the problem with incorrect connection, first of all, disconnect all pipes from the radiator. Reconnect the pipes so that the water supply is through the top connection and the outflow is through the bottom hole.. After that, check the result of the work.

Another problem that keeps the lower part of the heating radiator cold is the reduced rate of water circulation inside the element. This situation may arise for two reasons. Firstly, one of the pipes has a narrowed section, and secondly, the water moves extremely slowly directly in the system itself. In the second case, the bottom of the radiator is cold due to a lack of pump power, which is responsible for pumping the coolant through the system. In this case, the liquid cannot quickly pass the radiator and flow further. Such a problem is typical for gravity systems that lack additional details.

Pipe narrowing can happen for several reasons. Firstly, this is the result of improper soldering of polypropylene pipes. Secondly, pipes can become narrower due to the installation of a control valve with a narrower section. Thirdly, deposits can form in the pipes that prevent normal throughput. Another reason for the inefficient operation of the radiator is that it is extremely low temperature in the room. Because of this, the element cools much faster as it gives up all of its energy. In this case, it is quite normal that the lower part of the device is cold, and the top is hot.

If you began to wonder: “Why is the heating radiator in the room hot on top and cold on the bottom?”, Then it's time to urgently take the necessary measures.

Correctly connected battery

To find the cause, follow the following algorithm:

• check the correct connection of pipes;
• inspect the radiator itself;
• release the air and clean the device;
• check the condition of the valves for adjustment;
• examine the pipes;
• check the pump.

The first stage requires a connection literacy check. First, evaluate the temperature of the nozzle at the bottom of the radiator. If the device has been connected incorrectly, the lower connection will be hot. In order to solve the problem, you need to disconnect all pipes and reconnect them according to the above principle. If you do everything right, then the lower pipe will be barely warm.

Often an air lock forms in the radiator, which interferes with the normal heating of the element. To solve the problem, the device must have a Mayevsky valve or a separate seal for air release. To purge, it is necessary to shut off the air supply, fully open the descent and release all the air. Then the valve must be returned to its previous position and the valves of the system must be turned. In many cases, this procedure gives the desired result.

If the system is equipped with a control valve, then the problem may lie in it. Remove the faucet and inspect it carefully. If you notice a narrowing of its end, then you will have to return the parts to their original diameter using pliers. Many experts advise immediately changing the tap in order to extend the life of the system.

If there is no tap, then most likely the problem lies in the pipes. We advise you to remove the channels with a special removable key, clean them from rust and other contaminants. If the pipes are no longer serviceable, replace them with new ones.

Often there is no high pressure in the system, due to its design features. You need to find out about this when buying an apartment or a private house. To increase this figure, replace the old pump or buy one if the pump is completely missing. This will make it possible to increase the circulation rate of the coolant and provide more efficient work the entire system.

Why is the radiator hot on top and cold on the bottom?

The heating radiator is hot on top and cold on the bottom - how to fix the situation? Very often, residents of private houses and apartments ask themselves the question: “Why are the batteries hot on top and cold below?”.

Cold radiator - problems and solutions

The heating period is a real test drive not only for public utilities, but also for owners of autonomous heating systems, and just residents of apartments. As practice shows, a cold radiator is not forever, the problem is solvable, albeit unpleasant. In order to understand the cause of the phenomenon and possible solutions, let's turn to physics.

A photo that practically visualized the problem.

back to school

You can't live like this all winter.

A little recalling the laws of thermodynamics, imagine the movement of hot water or coolant in a closed system:

• Water, heated in the boiler, with the help of a pump accelerates through the system and enters the radiators;

For reference! We won't get into the complexity now. expansion systems, which stabilize the pressure and allow this circulation to take place. Let us only remember that getting into batteries, which have significantly larger area compared to pipes, water begins to give off heat and cools.

• After passing the radiator, the water gives off heat to the metal, which in turn heats the air in the room;
• Going down, the liquid leaves on the way back to the boiler, where it is again heated. Everything. The cycle is closed.

This is how, in a primitive presentation, the movement of the coolant in the system occurs.

Any problems?

Yes, there are problems, and they can be of two types:

• Radiators are completely cold;
• The top of the radiator is hot - the bottom is cold;

Note! Practice shows that the causes of both problems are absolutely identical, so we will consider their nature and solutions in a single context.

From this image it is clear that the bottom of the battery is cold!

And before moving on to solving the issue, let's recall one more feature of the state when the bottom of the radiator is cold - and the top is hot - natural. The heating of the top and the relatively cold bottom are natural processes, in poorly heated rooms, this difference is especially noticeable. But as you noticed, the word used was comparatively cold, not icy.

Every event has a reason

And if so, then covering the problem of why the radiator is hot on top and cold on the bottom, we immediately indicate that there are four possible reasons:

• First reason initially incorrect connection of the radiator;
• Second- air pockets;
• Third- incomplete opening of shut-off valves, or valves with a reduced cross section of the passage were used during installation;
• Fourth– the presence of dirt and deposits in the radiators.

As we mention and understand.

Not everyone knows where is the entrance, where is the exit?

Connection errors

If your battery is connected incorrectly, it's easy to check. According to physical laws, the maximum heat transfer occurs when hot water or coolant moves from top to bottom. This suggests that the leading system should be located on top, and not below, and the return line should be vice versa.

Advice! System check in use metal pipes does not raise questions: we looked at which pipe comes up to the radiator from above, took hold of it with a hand - hot, then everything is fine, cold, so a rearrangement is necessary. Harder to figure out plastic pipes. Here, only the previous battery can be a guideline.

If it is hot, and the connection of the leading and outlet systems is identical, then this is not the problem at all. If there are differences, the system will have to be soldered.

Proper connection of the heating system is the key to heat.

As a result, you get a decrease in battery efficiency by almost half, the explanation for this phenomenon is very simple:

• The coolant, passing through a narrow pipe, enters the radiator and collides with the cold mass. According to the laws of convection, it rushes upward;
• Having reached the top point and having passed along the entire length of the battery, the coolant practically flies into the pipe - the return pipe;
• For all his short journey, all he managed to do was give off heat only to the upper part of the battery and the first vertical passage.
• The solution to the problem is the urgent replacement of connections. And remember, entry is only from above, exit is only from below.

Advice! If you do not have shutoff valves for the heating system in the apartment, then before turning off the riser, warn the neighbors and calculate the time you need to carry out repairs with a gap of half an hour for unforeseen circumstances.

If you are running a system long time and such a problem arose for you for the first time, the reason is not in the wiring diagram. Move on.

Air is my enemy

And again, physics is indispensable. Air is lighter than water, so it will tend to take the "dominant" position, that is upper floors, extreme batteries and similar niches.

It is he main culprit problems called why in two-pipe system the last radiators are cold. Because there is air.

What to do? Air entering the system with water is either vented or enters the radiator.

In this case, there is only one option:

• By opening the Mayevsky tap, you bleed all the air. The criterion for the release of air is the outflow of water without a characteristic whistle or hiss of airiness;
• Close the faucet tightly, making sure that water does not ooze;
• When working with autonomous system heating, feed the system by filling it with water until the pressure gauge needle enters the green sector.

The price of the solution is simple - remove the air.

Note! A small amount of water can also cause the above problems, so in houses and apartments with autonomous heating control of the readings of the system falls entirely on the owners.

A few words about fittings

Shut-off valves are designed and built in so that, if necessary, it is possible to remove the battery without turning off the entire system. For them, according to all technological calculations, two positions are provided - full opening and full closing.

Only in this case, the normal functioning of the radiators and the system as a whole is possible. But there are situations called "undercooked".

What happens in this case:

• A natural narrowing is formed at the place of passage of the coolant. As in traffic jams, in narrow places the speed of movement decreases, but the rate of heat transfer does not;
• While the water at low speed crawls to its top point, all the heat will be given away along the way. It will go down at room temperature.

Advice! Check the condition of the valves before starting heating season so as not to puzzle over the question why the radiator is hot from above - cold from below.

Mud, where?

Sometimes the cause of cold batteries is dirt accumulated in them.

Dirt is formed from the system. This and low quality water purification, and products of interaction of metal and water. Unfortunately, this process is difficult to control.

The appearance of dirt in the radiator can be diagnosed by the futility of previous measures.

In this case, we do the following:

• We close the shut-off valve on the radiator;
• We unscrew the connecting nuts and drain the water from the radiator;
• We remove the battery with our own hands, clean it mechanically and rinse it with water.

Finally

Summary! Some problems can be avoided with the initial and correct connection of the entire system, others require preventive maintenance.

Cold radiator from below and hot from above: do-it-yourself video installation instructions, why in a two-pipe system, photo and price

Cold radiator from below and hot from above: do-it-yourself video installation instructions, why in a two-pipe system, photo and price

Heating is complex system with their own characteristics. Many people notice that their radiator is cold at the bottom and hot at the top. Such a problem must be given attention. After all, the radiator in this case does not work at full capacity and, consequently, the temperature in the room drops. But if the temperature difference between the top and bottom of the radiator is small, then you should not worry. Let's take a closer look at the possible causes of this problem and how to fix it.

Popular reasons

In almost all radiators, the temperature at the bottom is slightly lower than at the top. It depends on high level heat transfer. In this case, the water cools down before it leaves the battery. With a small temperature difference, there is no cause for concern. A slight difference is quite normal. But if you notice that the lower part of the radiator is barely warm or very cold, then you should find out the cause and take measures to fix the problem.

Some reasons:

1. At self-connection radiator, you can confuse the pipes for return and supply. Also, using the services of an unskilled master, such a situation may arise. With such violations, a violation of the heating system occurs and the temperature from the bottom of the radiator drops.
2. Low water circulation inside the radiator. This problem is bad for battery life. Due to the low speed, the temperature cools down before leaving the radiator. There can be many reasons for this speed. It needs to be identified and removed immediately.

Other reasons

The most popular reason is a decrease in the flow rate of the coolant. There are several options why this problem occurs:

• Narrow section of pipe. A narrowing of the pipe may occur due to improper soldering of the pipes. This applies to pipes made of polypropylene. As well as possible cause there may be some deposits in the pipe. Often there is such a problem as installing a control valve with a narrowed section;
• AT heating system the coolant moves at a low speed. This problem occurs when the power of the circulation pump is low. In this case, the water does not move at the desired speed and cannot go into the branch. Basically, this problem occurs in gravitational systems, in which there is no additional equipment;
• Low temperature in the house. In this case, the radiator cools faster, as it gives a large number of its energy. Therefore, the bottom of the radiator becomes colder than the top.

To identify the cause, the condition of the entire heating system should be assessed and checked. Once a problem has been identified, it should be corrected for further normal operation radiator.

Incorrect pipe connection

If the pipes are connected incorrectly, the efficiency of the radiator will be reduced. Using the services experienced craftsmen, this problem does not occur. However, if you decide to connect the pipes yourself, then the assumption is possible major mistake. When installing a radiator, a return pipe is often connected to the upper pipe, and to the lower pipe for supply. This error causes the following problems:

1. The efficiency of the system is reduced and the water circulation is completely destroyed.
2. The process of removing water from the battery is disrupted.
3. Due to the decrease in the efficiency of the battery, as well as heat transfer, water cannot fill all sections evenly.

Water enters the radiator through the bottom pipe. Then it flows in a circle and is removed from the radiator. The operation of the radiator is significantly reduced, as the sections do not warm up well. When connected to the upper branch pipe, the liquid is not discharged from the inside. This is due to the characteristics of the radiator, which cannot create high pressure to remove water through the top.

So how are u cold water the density is less than that of a cold one, then when it enters the radiator, it tends to the top. The coolant passes a shorter path, while the liquid in the sections does not move.

If you connected the radiator correctly, then the water should come from above and flow through the upper manifold. The liquid will flow into the columns, and pass into lower part because the pressure in the radiator is low. With proper operation, the radiator will heat up evenly.

If, nevertheless, the pipes were connected incorrectly, there are several options for how to correct the situation:

• Disconnect pipes;
• Establish the correct scheme of work, in which the supply pipe is connected to the upper branch pipe, and the return pipe to the lower one;
• After completing the previous points, you can connect all the elements to the radiator, and then check its operation.

If you are sure that you connected the pipes correctly, and the radiator still remains cold from below, then you should look for other causes of the problem.

Troubleshooting

If you find that your radiator is hot on top and much colder below, then you should look for the cause. To do this, you need to perform a number of actions:

1. Check radiator connection. Have all the requirements for connecting the heating system been met?
2. Bleed air and clean.
3. Check the condition of the control valves.
4. Check the condition and connection of pipes.
5. Check circulation pump. Replace it if damaged or install it.

If the pipes have been connected incorrectly, the bottom pipe will be hot. In this case, it is necessary to disconnect the pipes and reconnect them, but already in right order. It will also be necessary to establish a scheme of work. If the pipes have been laid correctly, the lower pipe will be slightly warm. In this case, there are no problems with connecting pipes.

A common cause is the occurrence of air locks in the radiator. To avoid such a problem, a special air vent must be installed. Shut off the supply, open the vent and remove the air. Then you need to turn off the tap and turn the heating valves.

If you do not have a circulation pump or it has a low power, then the pressure in the heating system will be weak. And, therefore, the water will slowly move along the radiator. In this case, you need to purchase a powerful circulation pump.

If the heating system is equipped with a control valve, then the cause of the problem may be in it. It needs to be removed and checked. If there is a narrowing of the section, then you can increase it with the help of tools. Or even replace it with a new faucet. After that, you can make re-installation element.

If none of the causes listed above is a problem, then the condition of the pipes should be checked. Perhaps there are various contaminants that need to be cleaned. If the pipes have severe damage then you need to buy new pipes.

After studying the article, you can independently identify the cause of the problem. After a thorough inspection of the radiator and fixing the problem, you can establish a high-quality operation of the heating system.

You can't leave this issue unattended! And in order to solve it quickly and efficiently, it is necessary to understand all the intricacies of the heating circuit.

What does it threaten?

Incorrect battery operation threatens:

• a decrease in the efficiency of this node;
• drop in temperature in residential premises;
• decrease in home comfort;
• the inability to correct the situation through the adjustment of additional fittings.

At the same time, it should be remembered that a slight difference in temperature different zones radiator - this is a normal operating moment associated with the circulation of water and the peculiarity of heat transfer.

Causes

As already mentioned, any battery will have a slightly cooler bottom than its top. The level of heat transfer from any metal is quite high - the water has time to cool down faster than it leaves the radiator sections. For this reason, there is a temperature difference.

The problem can be diagnosed by the increase in temperature gap. The bottom of each section burns with cold, while the upper part is heated (sometimes it is dangerous to take the battery with your hands, the metal is so hot).

The most common reasons for this condition are:

1. Slow circulation speed of the working fluid.
2. Incorrect connection (the supply and return pipes were mixed up).

Violation of the correct installation scheme is not so uncommon. Many owners or unskilled craftsmen make the mistake of connecting pipes to batteries.

With regard to the circulation rate, it may already drop during operation. This happens for a variety of reasons, each of which requires immediate elimination.

Connection errors

Skilled craftsmen, of course, do not allow such oversights. But amateurs may well be wrong when installing heating. Most often, the return line is connected to the upper pipe of the battery. In this case, the feed is attached to the bottom. As a result, the removal of fluid from the radiator is disrupted, its efficiency decreases, and the entire system does not function correctly.

If you connect the supply pipe from below, the water flows around the battery in a circle and leaves it, while individual sections are not filled or warmed up. With the upper return line, the liquid cannot leave inner part design, because the radiator is not able to create increased pressure and squeeze out water through the upper pipe.

When connected correctly working fluid enters from above and gradually flows through all sections of the radiator, going down. After that, it enters the return line and is transported back to the heating boiler.

The error is fixed quite simply:

1. All pipes are dismantled (disconnected from the nozzles).
2. Provided correct scheme connections: supply from above, return from below.
3. All elements are attached to the right places. After that, the heating starts and its operation is checked.

The only difficulty is the danger of stopping the system during the cold season. Therefore, for new heating, it is recommended to carry out testing even before the onset of the first frost.

Speed ​​drop

There are three reasons for improper circulation:

1. Violations were made during installation, namely, the pipe sections were narrowed.
2. The coolant moves too slowly inside the system.
3. The room temperature is too low.

Slow circulation is typical for circuits without additional equipment. As soon as a pump is installed that provides forced circulation, the problem is completely solved.

The narrowing of the section occurs for several reasons. Rust or scale can build up in an old heating system. Or an adjustment valve with the wrong section diameter has been installed. As an option, polypropylene pipes soldered incorrectly.

In order to accurately determine the cause that caused poor heating of the radiators, it is necessary to carefully examine the circuit and analyze its condition.

Cause Search Algorithm

Diagnosis procedure:

1. At the first stage, you should check the correct connection of the pipes.
2. Then the radiators are inspected. The accumulated air is drained, as often the reason for stopping the coolant is the formation of a plug. For this purpose, special Maevsky valves and taps are provided in the system. The water supply is shut off first! Then the air is released.
3. The next step is to assess the condition of the release valves. Often the problem lies in the taps and shutoff valves. It must be dismantled and cleaned from contamination. But it is better to replace these nodes with new ones.
4. It is recommended to flush the pipes under pressure or start and drain the coolant several times. Old pipelines are replaced with new ones, because it becomes more and more difficult to remove or clean pollution over the years.
5. At the final stage, the circulation pump is mounted, if it has not been installed before. An already functioning node must be checked for breakdowns. Sometimes circulation drops due to low power pump (for some models, the speed can be adjusted).

With the correct operation of all units and heating elements, the lower battery pipe will be barely warm. This will indicate the complete elimination of the problem.