Central heating in a private house no circulation. Why is the radiator hot on top and cold on the bottom?

The second article from the troubleshooting cycle in the heating system

Troubleshooting in a two-pipe heating system (continued)

Quite a lot of time has passed since the writing of the first article, and on the eve of the heating season 2011-2012, I decided to continue the cycle, especially since questions on the topic "I did the heating, but it does not work" continue to do.

Unfortunately, troubleshooting methods that do not lie on the surface are quite difficult to classify, and I decided to dedicate a few small articles to the issue of heating system malfunctions. In this article, I would like to consider the problem of poor coolant circulation and uneven heating of radiators. I myself have never made mistakes like those described and, accordingly, here I will have to theorize a little.

Friends! Before troubleshooting your heating, please find the dirt filter and clean it! Perhaps after that there will be nothing to look for!

So we have two-pipe heating. Let's consider one branch of this heating system serving, let's say conditionally, one floor. Here is her diagram. The water flow is shown by arrows.

The radiator located closer to the beginning of the branch, or to the boiler, is hot. This is the leftmost radiator. There can be significantly more radiators than shown in the diagram. For example, in my tiny house there are 3 branches. The longest has a length of about 25 meters and it has 5 radiators. The problem is that the radiators following the first are either completely cold or have a temperature much lower than that of the first. Moreover, the farther to the end of the branch, the colder and colder the radiators.

Our first radiator is hot (the hand can hardly stand it). We feel the next ones and find that all the radiators are hot, but their temperature decreases as we move along the branch. The latter is no longer hot, but slightly warm. We return to the first radiator, but we feel its bottom. We feel the bottom of all the radiators along the branch and find that the bottom of the radiators is much colder than their top. Even the first one.

We have water circulation in our heating branch. There is no air in the pipes. However, circulation is not fast enough. It is so weak that the water has time to cool down while moving from the radiator inlet to its outlet. Thus, the problem is diagnosed. We just have to find its cause and destroy it.

Do we have a circulation pump in the system?

If it is not there, then the problem of circulation acceleration is rather difficult to solve. It is necessary to put the boiler lower, it is necessary to increase the diameter of the riser, it is necessary to increase the diameter of the supply and return (horizontal lines) it is necessary to change the pipes to those in which inner surface smoother, you need to reduce the number of corners and make them obtuse, that is, 100 or 110 degrees. At least more than 90.

If there is a circulation pump, then ... solving the problem is not at all easier.

First, let's check if the pump is working. To do this in the general case is not as easy as it seems. A good circulation pump runs absolutely silently and without vibrations. You can only hear his work by putting your ear to him, and he is hot and you can get burned! I do not recommend you, dear friends, to risk your organs! Stock up on a medical stethoscope or just a large diameter tube (a piece of plastic pipe from a sewer with a diameter of 50 mm will do. Attach one end to the motor, and stick your ear into the other end. If you can hear the motor running, that's good!

By the way, if your motor is noisy, then it may have broken down and needs to be replaced so that it does not become painfully cold, but it is much more likely that air is seething in it. Maybe because of this, and the circulation is weak? In this case, turn off the motor and bleed the air. On any motor there is a means for this. And you can drain the water from the pump right while it is running, but this must be done very carefully so that it (the motor) does not break. As soon as water with bubbles stops coming out of the motor, the air release procedure must be stopped, that is, all holes must be screwed and added to the fresh water system, bringing the barometer pressure to the desired level.

Important note!

Re-reading my especially successful articles, and this article is undoubtedly quite successful, I noticed one inaccuracy. It concerns the descent of air on a running pump. The fact is that if your pump is especially powerful and creates a noticeable pressure, then the air bleed procedure can turn into airing the entire system. The point is that the pressure of the water is so great that air is sucked into the system, but the water does not pour out. It depends on the design and power of the pump. Possibly some other factors as well. In short, if bleeding is a problem in your system, be sure to turn off the circulator before bleeding. Extra caution won't hurt!

Is the pump running? Fine! Is it possible to increase the circulation speed on it? Amazing! Let's zoom in and see what happens. If all the radiators have become evenly hot, then we believe that we simply have a too long branch and we used too thin pipes. It is possible that the pipes Bad quality or are there any obstructions to circulation in the form a large number corners, dents on pipes and so on. Then we make a promise to ourselves someday to redo everything and live in peace. Well, maybe we change the circulation pump to a more powerful one. At the same time, we put up with increased electricity costs. What did you think? Is it so simple in big house live? Everything has to be paid for.

Suppose that increasing the circulation speed on the motor did not give anything.

We think it's a miracle! Something had to change, or the motor is faulty, after all. At least on the first branch radiator, the bottom should get almost as hot as the top. Let's assume there was no miracle! On the first radiator, both the top and bottom became hot, but further along the branch, the temperature still does not suit us.

I hope you have valves at least at the inlets of all radiators? We close the valve of the first radiator halfway and feel the rest. Did they get hotter? If yes, then we draw the following conclusion.

We have received such heating in which it is easier for water to pass through the radiator than to go along the entire branch. Why did it happen? Well, for example, because the diameter of the supply line (or return line, which is the same) is smaller than the diameter of the pipes for the inlet and outlet of the radiator. And it should be the other way around. The passage diameter of the lines must be greater than the diameter of the outlets to the radiators. If you use high-quality, for example, copper pipes, then pipes of no more than 15 mm inner diameter should be connected to the radiators. That's enough! Verified by your obedient servant!

After reaching this remarkable conclusion, we think that we got off lightly and live by regulating the circulation in our branch with valves. This, of course, does not add comfort. We change the valves to automatic thermostatic ones and we get, I hope, quite normal heating, which regulates itself. After that, we live in peace.

Next option. Both lines are hot, but the radiators are cold. In this case, the valves on the radiators are fully open.

By and large, this is also a miracle. In this case, the radiators cannot be absolutely cold. But if water rushes along the highways at the speed of a racing car, but does not enter the radiators, then this means that the problem is either in the radiators in all at once), or in the node connecting the radiator to the highway, and not necessarily the upper node, the input, so to speak . If the problem is in the lower, output node, then the effect will be exactly the same. In other words, if we block the radiator outlet, it will be absolutely cold, as if we had blocked the entrance. Why are control valves placed on top? Just so that you don’t have to lean too low to adjust them, and you don’t accidentally touch your foot.

If we consider malfunctions of radiators, then it is much more likely that the problem will be in only one of them, but not in all at once. In this case, you need to deal with one. Most likely the valve is the problem. That's where I think it's worth starting.

And the last. If we have an air lock or blockage in the middle of the line, then what do we get? All radiators and the line will be hot before blockage, and the supply and return lines immediately after the working radiator will be cold.

NOTE!

If this happened, this does not mean at all that the problem is somewhere near the working radiator. The problem can be anywhere in the gap between the supply and return lines between a working radiator and the first non-working one. This is very important to understand! Understanding this crucial moment can save you a lot of time and effort. Yes, and money too.

I'm not too lazy to even draw a diagram

That's all. I hope this article has been useful to someone. As usual, I will be glad to comments and "accidents from life."

Article created 10/19/2011

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In water heating systems, it is not uncommon for a problem to occur that leads to a deterioration in the circulation of water inside the circuit. The problem has a specific name - airing in the heating system. Uninterrupted operation of water heating is built on the principles of circulation hot water(coolant) inside the circuit and heat transfer through radiators that heat the premises. The air in the system leads to the appearance of air pockets and, as a result, to the inefficient functioning of the entire system due to a decrease in heat transfer.

To begin to solve the problem, it is necessary to establish the causes of the appearance of air: natural or artificial. To natural cause airing of the system is due to the property of heated water to release air. The higher the coolant temperature, the more air bubbles. According to physical laws, the accumulation of bubbles occurs in the upper part of the circuit, since air is lighter than water.
The rest of the reasons are considered artificial. It is difficult to give a complete list, but the main reasons are considered to be the following:

• lack of pressure in the system;
• errors in the installation of the heating circuit (for example, incorrect pipe slope);
• errors when starting the system into operation (for example, filling the circuit with water too quickly);
• high concentration of air in the water used;
• incorrect operation of the locking equipment (possibly loose connections individual elements);
• blockage of pipelines;
• consequences of repair and maintenance work;
• corrosion on metal surfaces contour elements;
• incorrect operation of air vents or their absence.

Consequences of airing

The disruption of heat transfer due to air locks is unpleasant for residents who pay for heating, but in fact receive an underestimated indoor temperature. But this is not the only negative, there are other negative consequences:

• noise and vibration during water circulation, which in the worst case is fraught with the destruction of integrity at the junction of the circuit elements;
• defrosting the system if there is no water circulation in several radiators;
• excessive fuel consumption in order to increase heat transfer;
• destruction of internal metal parts under the influence of air (due to corrosion).

The totality of all the consequences affects the operating capabilities and the overall service life of both individual elements and the entire heating system.

De-airing

Airing can occur when the system is filled with coolant and during operation. Situations are resolved in different ways, but it all comes down to air release using valves and taps built into the system.

filling closed system with forced circulation must occur in a certain sequence in order to exclude the formation of air pockets. Innings cold water is carried out from the bottom up, the air outlet valves are left open, only those installed for draining water are closed. Rising, the coolant squeezes air through open valves and taps. As water begins to run through the tap, it is closed. So gradually, always smoothly, fill the system with water. The pump is started when the circuit is completely filled with coolant.


For air release, manual or automatic air vents, air separators are used. It is clear that the installation of manual air vents involves the release of air by the attendants or the tenant of the apartment (house). There are such air vents in ordinary residential buildings indoors upper floors or on technical floors. The Mayevsky crane is known to many residents of old high-rise buildings, who each heating season release the accumulated air. In new houses, it is practiced to install a manual drain valve on technical floors.


The automatic air venting system works separately from human participation. The principle of operation of automatic air vents is the same. In the body of the air vent there is a float on which water enters. The float presses on the spring-loaded rod, opening access to the outside. The body is gradually filled with coolant, the float presses on the rod and closes the outlet. In order for the air vent to work properly, periodically check the cleanliness of the needle and the suitability of the sealing ring for further operation.

The need for separators arises during the operation of heating systems large sizes where manual reset is problematic. The separator copes with the removal of air dissolved in water. It converts the air into bubbles and removes them from the system. In parallel, the separator (depending on the model) can trap impurities that are present in the coolant (sludge).


All air vents are mounted at critical points - at pipe bends and in high points contour.

This article lists the main malfunctions that can happen to the heating system of a private house, as well as ways to fix them. Troubleshooting the heating system can be divided into two types. Do-it-yourself heating system repair can be made in terms of wiring the heating system: radiators and fittings. All problems that arise in the part of the boiler room and equipment require special knowledge and experience, therefore heating system repair related to equipment, it is better to entrust specialists.

Those questions that the owner of the house can solve himself are listed below.

Battery does not heat up

If one or more radiators do not heat or heat poorly, then the first step is to check if there is air in them using air vents. If from descenders water is coming, and the radiator still does not heat, then you need to make sure that both taps of this radiator are open (such inattention can often occur). The next step is to check if the radiator is clogged. To do this, other heating radiators that heat and are on the same branch as the idle one must be shut off so that all the water goes through this radiator. If he began to warm, then he is not clogged. In this case, it is necessary to carry out hydraulic alignment of the branch. in plain language, it is necessary to cover the remaining radiators on the branch, so that the non-working one gets more. You need to be prepared that the alignment will take more than one day, because the heating system may be slow to respond to changes in settings. If the valves in front of the radiator are fully open and it is cold, then it is clogged (extremely low probability). Primarily, may not heat the last radiators on a branch. But this can always be eliminated by hydraulic leveling. If someone tells you that "it does not pump there" or "insufficient pump power", do not rush to believe and touch the pump or pipes. In order for the pump to "not pump" it is necessary to "try hard" during the installation of the heating system. If one or more of the last radiators do not heat up even after working with taps, then there may be an air lock in the pipes (see.

Pressure drops in the heating system

Once again, we focus on the fact that the heating system after launch should work for several days or even weeks. Air is dissolved in the system, it gradually comes out on automatic air vents and with manual deaeration of radiators. This results in a loss of pressure. At first, frequent replenishment of the heating system is normal. If the system has been running for more than a month, and the pressure drops, then you can check this version. If the volume of the expansion tank is incorrectly calculated, pressure surges in the heating system are possible, as a result of which the safety valve may operate and discharge water, as a result of cooling - a pressure drop. If everything is in order with this, then there is a leak in the system, which is not pleasant, you need to look for a leak.

Pressure drops in the heating system

The expansion tank is responsible for compensating for changes in the volume of the heating system. Therefore, if the pressure changes with temperature large range, then the reason is expansion tank: either it is broken or there is an incorrect volume calculation expansion tank. This may lead to operation safety valve or stop the boiler due to insufficient pressure. see pressure, volume of the heating system and selection of an expansion tank.

Return is hot, supply is cold

Why is the return flow hot and the supply cold? This is a rare occurrence. It can be observed when the pump is installed in reverse and without check valve. This is also possible due to the operation of the floor heating pump. When the floor is just started and heats up the structure, it works at full capacity and can, under certain circumstances, change the circulation in the radiator circuit. As the floor warms up, this may self-correct. If the pipes are hidden, then you need to check if the pipes are mixed up (supply with return). Can different ways: water or just blow.

No circulation or poor circulation in the heating system

The boiler is working, the pump is definitely working, but there is no circulation in the heating system. Again, the first thing we do is check the air in the radiators. Then, we check stop valves(taps) that can be closed somewhere due to inattention. The next step is to clean the filter in front of the boiler and in other places, if any. This will solve the issue in 90% of cases, even if the heating system has recently been installed. If not, then we check the heating pipes for the possibility of air locks in the pipes (see installation of the heating system). If there are such sections in the heating distribution, then you can temporarily solve the problem by draining water from the radiator under pressure. which is behind the loop, the flow of water will expel the air from the loop. If possible, an automatic air vent should be installed on large hinges. This will eliminate the problem in the future. If, as a result of the above measures, circulation is not restored, then you need to contact a specialist.

Discuss this article, leave feedback in

A breakdown in the heating system, imperfections, flaws, everything leads to cold radiators. If there is no coolant circulation, then the cause must be determined. Most often, the answer to why the heating does not work is on the surface, it is obvious.

We will analyze in order the main causes of heating malfunctions, why water does not circulate through the pipes, and what needs to be done first.

Let's start with the simplest and most obvious reasons.

Clogged, messed up.

Every heating system must have a filter. coarse cleaning. Not at all a large device with a fine mesh and a sump (installed down! As a last resort, to the side) saves equipment, pumps, and the boiler from contamination of the coolant that will be present in any system. Chips, scraps of threads, rust, sediment from the water .... everything is delayed by the mesh in the filter.

The sump must be periodically untwisted, the mesh should be cleaned.

If circulation is disturbed in the heating system of a private house, then the first step is to check the filter, which should be installed on the return line in front of the boiler.

Air in the system, airing

Airing can occur in any closed piping scheme where measures are not taken to remove the air. Air is always present in the coolant, including in a dissolved state, it is released during pressure drops, and accumulates at the highest points. Including the boiler.

Automatic air vents are installed at the characteristic, highest points of the system, as well as on collectors and on special separators - the normal circuit is equipped with a special air trapping device in which air bubbles are released from the coolant.

In addition, Mayevsky taps (manual air vents) should be on each radiator, and possibly also in other elevated places.

Check airing, bleed air, install air vents - common actions if circulation stops and batteries are cold.

Circulation pump not working

In private homes, the reason for the cessation of the heating system is the breakdown of electrical equipment, which controlled the movement of the coolant through the pipes.

If the heating suddenly stops working, then you need to check the operability of the circulation pump near solid fuel boiler or a pump in an automated boiler. In addition, the same unit can be installed in each circuit, which should work properly.

Bad polypropylene pipes

Often the consumer (customer) believes that polypropylene pipes are absolutely reliable and cannot cause problems with heating, cool batteries.

But polypropylene is much more insidious than old steel or metal-plastic pipelines. Each place of soldering (welding) is a potential increased resistance in the system or the reason for the termination of circulation (weakened movement of water through the batteries), due to buildup of material inside.

It is impossible to control the quality of the connections from the outside, it remains only to cut out the pieces, solder, remake the polypropylene pipes again.

Incorrect operation of the polypropylene system is a real problem for the home installer. Good professionals for this material are not taken at all.

Bad project

It is not uncommon for poor circulation to occur where design is poor. Typically, the batteries are not switched on correctly, according to a certain sequential scheme, where the last battery in the scheme receives much less coolant.

Another bad project is single-pipe circuits, where it is also difficult to establish the necessary circulation of the coolant through each battery.

If the radiators do not heat up evenly, there is poor circulation of the coolant on individual heating devices, first of all, you need to consider how appropriate the connection is classical schemes- shoulder, associated, radial. It is necessary to bring home heating to customary norms design, and then expect good circulation from it and the same heating of the radiators.

Small diameter, overgrown pipes

old steel pipes from the inside they are overgrown with rust, deposits, their throughput capacity decreases significantly over time, and there is only one solution - they need to be changed to modern ones.

But even during installation, for the sake of economy, mistakes can be made with the choice of pipeline diameter - on highways, on groups heating appliances, diameters of 16 or 20 mm can be set. As a result - noise in the pipes, excessive consumption of electricity, lack of coolant flow.

A complex system

A variation on bad design is a poorly designed complex heating system consisting of many heating circuits and several boilers. Here, entire circuits will already work incorrectly if the work of one affects the neighboring one.

As a rule, one boiler (reserve does not count) and three circuits - a boiler, radiators, a warm floor with their pumps are coordinated normally, and there are no questions. But if you connect another working boiler plus a circuit (for example, heating a garage and a greenhouse), then the system will become complicated. It is difficult to say how the coolant will circulate in it without pressure equalization at the connection points.

AT complex systems a competent project is important, the installation of a hydraulic switch or an equal pressure ring, you can learn more about the hydraulic separator

No balancing

Many schemes home heating imply balancing, balancing, adjusting cranes are installed in them. For example, between floors, between shoulders, and for each radiator. Cranes cover the direction with less hydraulic resistance, respectively, more will go to other points of the coolant.

Children can play with cranes. Or initially the system is not balanced. Setting up, as a rule, is no problem, you just need to find this tap ....

Neighbors don't provide heat

But complex schemes heating projects are of little concern to residents of high-rise buildings, who have a separate riser for each radiator in the apartment. And if any radiator ceases to heat up normally, then there is no circulation through the riser, therefore ...

You need to contact the heating network, the housing office (service organization) to adjust the power through the risers, and if this does not help, then with the requirement to check the neighbors.

Often unauthorized connection, replacement of radiators, pipes in systems central heating leads to a redistribution of pressure, the circulation in individual batteries decreases, disappears.

No circulation in gravity system

In gravity systems, the pressure difference is low, they are especially sensitive to air pockets, pipe diameters, gaps in radiators.

In old schemes, gradual deposits occur in radiators and pipes, circulation may decrease over time, and the only treatment for this is to replace everything with a more modern one.

You also need to pay attention to the correctness of the circuit itself - the middle heating line is below the cooling line (the boiler heat exchanger is below the radiators), and also - the hot supply rises up to the highest point, and from there it descends to the radiators ... Read more about gravity flow circuits

Various breakdowns in heating systems

• Closed, faucets valves - check if everything is open to ensure circulation.
• Leak in the system - there is little coolant, check the pressure, eliminate the leak.
• Installation with flexible pipes - the pipe is pinched.
• Breakdown of automatic equipment - thermal heads on mixing units, radiators, themselves mixing units- siltation, failure, it is necessary to check the correct operation. It's also electronics failure.
• Incorrect balancing on the distribution manifold - in beam schemes, complex systems, manifolds with balancing and tuning equipment can cause a lack of circulation anywhere, due to breakdowns and incorrect settings.
• Low pressure, no air in the expansion tank - check the pressure in the pipes and pumping the tank, automated units will not work at all without the right pressure.
• Violation of the circuit, excess bypass - check the installation for compliance with the project, the logic of the circuit, for jet shortings, parallel branches to radiators and circuits.

The heated towel rail is a multifunctional device that can simultaneously perform both heating and drying functions, and also serves as a design element. It's quite reliable equipment on which the microclimate of the bathroom depends. However, nothing lasts forever and in some cases this device can fail. Why this happens and what reasons can lead to the fact that the heated towel rail ceases to perform its main function, namely, it does not heat, we will consider below.

How does a hot water heated towel rail work: its main types

Today, the market can provide a huge variety of various heated towel rails. They differ in shape, the material from which they are made and the method of heating. Basically, there are three types of this device: electric, water and combined.

This fixture is a definite must for any bathroom. Thanks to the heated towel rail, the bathroom will be constantly heated, and this will not contribute to the formation of dampness and mold on the walls. And also with the help of this device it will be possible to dry towels and small things.

The principle of operation of the heated towel rail is to heat its surface and transfer heat to the room. Each type has its own principle of operation. For example, an electrical appliance is heated by a heating element, and a combined one is generally heated in two ways, both from electricity and from water. But the water one works on the principle of an ordinary battery, that is, this type is heated from hot water.

The principle of operation of the water device:

• Hot water through the main heating pipes enters this device;
• There it passes through its entire length, giving off heat;
• Then the water leaves this device and gets back into the main heating system.

There is nothing difficult in this process, you just need to do competent connection this appliance to heating system. To do this, it is imperative to maintain the angle of inclination and select the correct diameter of the pipe, otherwise the heated towel rail will work poorly, intermittently. For better work water appliance install an additional special pump that circulates water inside. With such a circulation pump, the temperature of the device will be constant.

Installation features: how to start the heated towel rail

Before you install a heated towel rail, you first need to select it. For apartments, it is recommended to choose appliances domestic manufacturer, which will comply with certain GOSTs, since imported ones may not be suitable for our tie-in. But foreign brands are quite suitable for private houses.

The water heated towel rail will only work in heating period, and then just serve designer decoration. If you want the device to function all year round, then you need to install combined view this device.

It is also impossible to allow the pipes of the device to be of a smaller diameter than the main system. If this happens, then you need to select and install the necessary adapters. For basic connections, it is best to use "American". They will allow, if necessary, to easily and without problems remove the entire device. It is also recommended to install for convenience Ball Valves and special jumpers.

Towel dryer installation:

• First of all, the device must be assembled: for this, it is necessary to put shut-off valves on the supply line, which have detachable connections;
• Attach the assembled device to the wall;
• Run pipes from the main riser.

Having done all these actions, you can proceed to the initial launch of this device (towel dryer). To start the device, we need a pre-installed Mayevsky crane, which is usually located at the top of the device. Having opened the tap, you need to gradually fill the entire device with water so that it does not become airy, that is, air pockets should not form. In order for the launch to go right, you need to have great professional skills, and not just turn off the water.

The heated towel rail in the bathroom does not heat up: why is this happening

The heated towel rail should generally work without any interruption, however, some breakdowns can occur with it. But do not despair and make hasty conclusions, run after a new device. It may also happen that the device needs to be repaired.

A water appliance usually seems more reliable than an electric one. However, this is not at all the case, because some breakdowns are very difficult to fix. This is due to the inconvenience when working with such a device.

There are not many main reasons why the device stopped working. Some of them are trifling, while others require special attention and assistance from a qualified professional.

Causes indicating a malfunction of the device:

• Clogged suitable pipes;
• Malfunction of cranes;
• Lack of water circulation;
• The contamination of the device itself.

To determine some malfunctions of an electric heated towel rail (the device stops heating or cools quickly), you will need special device and indicator screwdriver. And also check the mains voltage using an ohmmeter. If after that it is still not possible to turn on the device, then the problem lies in the device itself. Carrying out all work with electrical appliance safety rules must be strictly observed, all tools must be insulated.

No circulation in the heated towel rail: reasons

Having done all the procedures to eliminate blockages and pollution, and the device is still cold. Then everything indicates the absence of coolant circulation inside the device. This problem is the most difficult, as it requires turning off the entire heating system and removing the appliance.

A special pump, which is designed specifically for these purposes, will also help to cope with the circulation in the device. Also, the reason for the lack of circulation is not correct connection or simply lack of water in the system.

Each breakdown has its own characteristics, so the repair is carried out individually. If there is no circulation in the device, then this may be due to several reasons.

Reasons for the lack of circulation in the device:

• The device was installed on hot pipe not correct, namely there is no return;
• The heated towel rail was installed on the hot return pipeline;
• The return line was placed above the level of the device itself.

If the failure is inherent in at least one of these reasons, then you need to make some changes to the installation, and this will cost you a significant amount. The easiest way is to simply change the water appliance to an electric one.