For normal operation of a gas boiler, soft water is needed, the supply of which is ensured by installing special filters. Today there is 3 types of devices: electromagnetic, cartridge and polyphosphate.
Why use filters for a gas heating boiler
The main purpose of the filter for purifying water entering the gas boiler in the house is uninterrupted supply of impurity-free water to the device, which will not leave scale.
In the process of passing water through the device, it is purified from salts.
If you do not use the device, then the capacity of water nodes will decrease, the automatic valve on the device will break, and gas and electricity consumption will increase over time.
Varieties
To reduce the risk of boiler breakdown, enhance the accuracy of measuring instruments and ensure long service life of equipment, it is important to understand the main types of devices and choose the right one.
Polyphosphate
Polyphosphate plants are considered budget option preliminary cleaning and softening of water entering the boiler.
The operating principle of such a device is to pass liquid through a flask filled with special crystals. They provide formation of a protective film on the inner walls of the boiler, and also slow down the formation of scale.
Photo 1. Polyphosphate filter for a gas boiler, filled with special crystals. They slow down scale formation.
The devices have a simple design:
- drain;
- flask;
- filler;
- lid.
The liquid enters the flask with filler through the lid, where it is passed through polyphosphate crystals. Next, it goes through the drain into the gas boiler tank.
Any device of this type requires periodic replacement of filler- sodium salt crystals. As a matter of fact, this is the only difficulty in servicing them. The average service life of such a treatment plant is up to one and a half years.
Electromagnetic or magnetic for softening hard water
Electromagnetic The devices are expensive, but the price is completely justified: the installation lasts a long time and allows you to get perfectly clean water at the output.
The principle of operation is that when the liquid passes through the flask, the salts in it disintegrate. Thus, scale will not settle on the walls of the boiler. Instead, the filter itself will be clogged with tiny salt particles, which is periodically washed.
Photo 2. Three magnetic filters for a heating system boiler; the scale in them breaks down into tiny particles.
Another characteristic is that under the influence of electromagnetic radiation, not only does scale disintegrate into small particles, but also a thin film is formed, which covers the boiler heat exchanger. Thanks to this, it remains protected and does not corrode for a long time.
We should not forget that electromagnetic and magnetic devices are different settings. At the heart of both is a magnet.
Attention! Electromagnetic devices more powerful, as they require connection to the electrical network. Ideal for gas boilers, as they perfectly soften water of any temperature. Magnetic installations less strong and it is not recommended to use them for gas boilers if the water hardness is too high.
Magnetic The devices consist of a metal case, inside of which there are a large number of strong magnets. Electromagnetic devices are additionally equipped with an electric drive, the operation of which allows the effect of magnets to be greatly enhanced.
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Cartridge for cleaning
Cartridge devices have low throughput. The following device types exist:
- Mechanical - traps small debris. Such devices need to be cleaned frequently, and they do not soften the water.
- Carbon - purifies water using activated carbon, acting as a filler. If you do not change it in time, the water will become even more contaminated as a result of passing through the filter.
Photo 3. Four low-flow cartridge filters are needed to purify the water.
- Ion exchange cartridge devices are considered the best because they change water hardness, entering into a chemical reaction with calcium and magnesium ions.
- Osmotic - allow molecules of water and gas to pass through them. This allows you to clean the liquid from metal impurities and harmful microorganisms, but it will not be possible to soften the water by installing such a filter.
- Membrane - purify water from debris and impurities, but do not soften it.
Important! Cartridge filters not suitable for gas boilers(except for ion exchange devices). They are more focused on purifying water that is intended to be drunk.
Before buying a filter for a gas boiler, you should consult with a specialist, who will recommend a suitable device and make recommendations.
But it should be remembered that you will have to constantly change the filler and the service life of these filters is shorter compared to electromagnetic ones.
- When choosing a device, you need to immediately decide where to install it. Sometimes installation requires a large space, which is not always possible.
- Be sure to make sure you have a warranty card. Good manufacturers of such devices never sell their product without providing a guarantee for it.
- It is preferable to purchase devices from well-known brands, since such products are more difficult to counterfeit. Often, unscrupulous sellers sell counterfeits under the guise of a well-known brand at a very low cost, so you should also pay attention to differences in prices for filters from the same manufacturer.
- If the tap water is hard, then in order to better protect the gas boiler It is recommended to buy two filters at once, focused on different degrees of water purification.
- To simultaneously soften the liquid and protect the internal parts of the boiler from possible damage, it is better use devices that soften water and have the ability to create a protective film on heating elements.
Features of installation in the house
The process of installing a water filter for a gas boiler depends on what kind of filter we are talking about. But there is general procedure.
Materials and tools
Before installation, you need to prepare everything you need so that the work does not take much time:
- brush for preliminary cleaning of pipes leading to the boiler;
- tool for carving plastic pipes;
- fum tape;
- tow;
- pliers;
- device for soldering plastic pipes.
All of the listed tools must be present in the arsenal during installation. You also need to have on hand installation instructions a specific type of device in front of the gas boiler.
Selecting and preparing a site before installation
Equipment installed directly in front of the pump, since installation in another place will be pointless. The pipes into which the filter will cut must be free of dirt and scale, so you should first clean with a brush or a special brush.
Important! The place where the device is supposed to be installed must be accessible for further maintenance of the device.
Installation
Installation involves several steps:
Each of us has a heating system at home. It is impossible to imagine any modern home without heating devices that provide full temperature conditions at any time of the year.
However, you need to remember that it is not enough to simply install a pipeline, connect the boiler to it and put it into operation. It is also necessary to take care of the quality of the water inside the pipes. A filter for the heating system copes well with these tasks.
What is a heating filter, why is it needed and what is it like? Let's figure it out now.
Why is it needed?
Let's imagine the design of the pipelines of an ordinary private house. Its heating system in 95% of cases consists of pipes and radiators that transport hot water.
Heating a house using pipes and water is an extremely convenient and effective way. However, many people forget that, just like when working with pipe systems for water supply, heating pipes and the heaters themselves also need to be protected from working with low-quality media.
Unfortunately, we cannot guarantee the quality of the water in the pipes, even if we get the bulk of the water from a well drilled ourselves.
Tap water often contains coarse and small particles of dirt, sand, small fractions of waste, chlorine, etc. Let's not forget about small organic waste or various metal elements.
The same applies, although to a lesser extent, to the quality of water from a well. It also happens that a well was not drilled in the best area. For example, the soil on your site has too much iron. In this case, the water will gradually become saturated with small iron elements, which negatively affect the insides of the pipes in the heating system.
But this is only a superficial analysis of several reasons why you may need a water purification filter.
1.1 What happens if you don’t install a filter?
Many people will ask, why do you actually need a heating filter? What's the use of it? This is not a water supply system, the water from which we constantly use for personal needs, hygiene, food, etc.
These questions are very reasonable. We will try to answer them. The main thing you need to understand is the importance of the heating system as a structure. Few people pay attention to it, especially if there are no breakdowns inside the house. However, believe me, if the heating system of a private house fails, you will notice it immediately.
There are several vulnerable points in heating pipelines:
- Heating circuit pipes;
- Circulation pump design;
Heating pipes are no different from water supply pipes. Except perhaps for a slightly reinforced structure, because their task is to constantly transport hot water.
They also suffer from poor-quality or dirty media, rust, and become clogged with waste. Considering the need for uninterrupted pumping of large masses of hot water, the rate of sedimentation even increases.
Sooner or later, the space inside will become so clogged that the passage of liquid through it will simply become impossible. The pressure inside the system will increase, which can lead to the most unpleasant consequences (take into account the influence of hot water) up to a breakthrough or failure of heating devices.
The same applies to radiators. Although the radiator cavity still suffers less from precipitation.
The design of the circulation pump suffers in a similar way. Unlike pipes, the chamber and inlets of the circulation pump are almost not subject to the negative influence of sediment, but large particles of debris and metal elements can create problems for them.
Over time, the condition of a circulation pump operated in a poor-quality environment will greatly deteriorate to the point of complete failure. This is why many plumbers recommend installing mud filters or coarse filters in front of the inlet chamber of any pump, especially a circulation pump.
However, clogged pipes, radiators or failure of the circulation pump are not such a big problem. In any case, it can be solved by simply replacing individual components or cleaning them.
What cannot be dealt with so quickly is a boiler breakdown. It does not matter whether you use an electric or gas heater, in any case it must be limited from working with contaminated liquid.
Without complete cleaning, the water in the heating chamber and tank will gradually clog the insides of the boiler. This will lead to a deterioration in its functional characteristics, frequent overheating, and in particularly advanced cases – to breakdowns.
2 Where to install?
Let's figure out where and how the heating filter should be installed. Installing the filter depends on what device we are going to install.
The coarse filter is used the least, but you can’t do without it. Mud collectors, as they are popularly called, must be installed so that they sift out large waste from all the liquid that enters the heating system.
It is advisable to install a coarse filter at the inlet of the system or at the inlet to the pump structure. If the pipeline is large, with a huge number of radiators, then it is recommended to install mudguards at all forks, especially between floors.
Fine filters perform more specific tasks and more of them are needed per pipeline as a percentage. They work best in tandem with mud collectors, but only if they are installed after the first ones.
A magnetic filter, which performs rather specific tasks of removing metal particles from the flow, should be mounted at the entrances to the system, and also for safety, in front of the heater inlet pipe.
2.1 Types and differences
When choosing a filter for a boiler, you need to pay attention to its types. We have already partially noted several of the most popular types of filters.
There are filters:
- Rough cleaning;
- Fine cleaning;
- Magnetic.
Let's look at each option separately. Let's start with samples for rough cleaning, since not a single heating circuit of any private home can do without them.
Coarse filters or mud filters are simple fittings that filter out excess particles from the flow inside the circuit.
Screening is carried out by a mesh element. The filter itself is a coupling with an oblique design. Inside the coupling there is a mesh filter, and also, if you have a modern model, a small outlet for waste accumulation.
The mesh element does not interfere with the movement of the flow in any way and does not slow it down in any way. Its task is to remove large foreign particles, that’s all.
The fitting for fine cleaning is usually installed after the mud trap. A mesh or membrane filter with small pores is already installed on it. The average pore diameter is 100 µm.
Thus, the device manages to filter out most of the waste that can then turn into sludge. These include various magnesium salts, particles of chlorine, rust, etc.
It has been proven that the presence of coarse and fine filters has a positive effect on the condition of pipes and radiators in heating systems.
It remains to consider the magnetic sample. The magnetic filter is somewhat different from those we discussed above. In it, the main work, as is probably clear from the name, is carried out by a magnetic mechanism.
The magnetic sample performs a simple and very useful task - it removes all remaining particles of iron and rust. Moreover, it does this thanks to two or four magnets located inside the coupling.
The benefits that a magnetic cleaning device brings to the heating circuit and boiler can hardly be overestimated.
2.2 Using coarse cleaning filters for heating (video)
2.3 Installation and maintenance
We will give some tips on how best to use a combination of cleaning devices to maximize the service life of heating systems in a private home.
From our point of view, it would be correct to use all types of filters. Don't skimp. The cost of a filter is slightly more than the cost of a regular fitting, but repairing or cleaning pipes will cost you much more.
We recommend installing a coarse filter at the system entrances. If the flow is small and goes through a single pipe, then one sample is enough. Otherwise, it would be correct to install one filter in the liquid pumping station directly next to the pump, and the second at the inlet to the heating circuit.
Magnetic filters are mounted directly in front of the entrance to the heating circuit pipes and additionally on the inlet pipe to the heater.
The cleaning elements must be cleaned from time to time, and if they are too clogged, they must be completely replaced.
It is advisable to remove the parts once a season, preferably in the summer, wash them under running water and change the cassettes if necessary.
Monitor the condition of the membranes and meshes inside the couplings. Loss of ductility and excessive convexity indicate excessive wear of the membrane. In this case, it needs to be changed.
The dirt trap in a home heating system is as small as it is important. An inexperienced viewer, contemplating the intricacies of pipes in a home boiler room, may think that such a small piptik - a coarse filter for the heating system - is just an unnecessary worry, you can do without it, because clean water was poured in... from the tap... Not suspecting that the mud trap is actually In fact, this is the boss of the heating system in his house. Next, let's look at where the dirt comes from, how to deal with it, how to install a filter in the system and how to clean it - why is the system clogged?
Where does dirt come from in heating, why is there no fluid movement?
Where does scale come from in a kettle, since clean water was poured in? But there are 50 kettles of water in the heating system - you can imagine how much sediment accumulates from it. And if the water changes, due to a leak, during the repair process, an additive will come accordingly. Also, a huge number of pieces of metal, enamel, thread, and something else “without a name” will be torn off from the entire internal surface of the system. But this is all child's play, compared to what happens if a corroded part is discovered, the whole mass gradually turning into sediment. And steel pipes can become sources of just mountains of rust.
What filters are used in home heating systems
In most cases, brass strainers are installed in the home heating system. They are simple, but they get the job done. All particles carried by the flow with a size of more than 0.5 mm are retained by a metal mesh and settle in the settling tank. The filter is extremely cheap, easy to install and maintain.
The most common thread diameter - 3/4 or 1 inch - is selected in accordance with the diameter of the main pipeline at the installation site.
Below are the characteristics in the photo of mesh brass dirt filters depending on the diameter.
Design options for rough cleaning of the heating system
Mud collectors of other designs are less common. The increased price of some does not provide benefits in most cases.
- Made from polypropylene - welded, and that's it...
- With additional magnetic catcher in the sump.
- With flush tap.
- On flanges, with pipe diameters greater than 2 inches.
- The body is made of cast iron, it can also be transparent...
How to maintain a dirt filter
If the system stops working normally, you need to inspect the dirt filter - tighten the sump cover nut. This is done carefully with the appropriate key. The seal under the nut is a copper washer, so a significant moment of force is needed to break the nut out of place, after which the rotation is already easy. A tray is placed to collect a small amount of coolant, which is inevitably lost when the sump lid is opened. Then the metal mesh is removed and cleaned.
But first you need to close the shut-off valves, which should be installed near the sludge filter on both sides. Otherwise, all the coolant from the system can be released through it, and the first portion will also flow under pressure...
The main rule for installing a mud pan
If you do not install the coarse filter correctly in the heating system, it will not work as expected, and blockages will occur without the ability to properly clean it.
The rule is simple - the sump must be facing downwards. It is under the influence of gravity that all trapped particles settle in the settling tank.
It is allowed, if the filter is positioned horizontally, to be turned with a sump closer to the horizontal position for ease of maintenance, for example, if equipment is in the way from below. But in any case, the sump should be turned slightly downward.
How to install a cleaning filter in a heating system, diagram
The filter is installed on the return line in front of the main equipment that it protects, as a rule, in front of the pump in a given branch or in the entire system.
With an automated boiler, the filter is installed on the return line before entering the boiler - between the shut-off valve and the boiler shut-off valve.
If the pump is remote, then a typical example of installing a filter in front of the pump is shown in the diagram; taps are also required to be able to service the filter, the service life of which is 1 year.
The expert advised: don’t get confused. Carelessness in installing the filter will cost the system a stop and possible equipment failure. An arrow on the body of the mud pan indicates the direction of fluid flow. Only install the filter correctly in relation to the direction of flow.
Filters for heating systems ensure the quality of the coolant inside the circuit.
This prevents the formation of rust on steel structural elements, which extends its service life.
They are divided into coarse filters, fine filters and magnetic devices.
What are filters for home heating systems?
Such devices have another name - mud collectors. Externally, they represent a pipeline expansion unit with a change in the direction of fluid flow and with a special mesh.
She prevents further movement of suspended particles through the pipeline. The devices are installed in such a way that maintenance is easy.
Types of devices
According to the degree of cleaning of mud collectors classified into several types.
Rough cleaning. What is a sediment filter?
The coarse cleaning device is an angular mesh filter with mesh up to 300 µm-micron. The device is also equipped with a drain in which dirt accumulates. This product is designed to clean coolant from large and small fractions.
Design
Depending on the design there are several types coarse mud collectors:
- By connection method devices with a pipe. There are flanged, welded and threaded devices.
- By location on the structure. This is a horizontal and vertical device.
The mudguard is made of brass, steel and plastic. The first option will withstand elevated temperatures. A steel device wears out quickly. A plastic product can only withstand relatively low temperatures up to +90 degrees Celsius.
One of the types of coarse mud filter is settling filter. This is an improved design equipped with a flask. It is located at the bottom of the device. When a large amount of dirt accumulates on the mesh, it falls down under gravity. Thanks to this, such debris accumulates in the flask and does not end up in the radiators.
Photo 1. Coarse settling filter for heating systems. Contaminants from the pipes fall into a special flask.
The design is also being improved separator. Air accumulates in it and enters the circuit. When its level reaches the limit, a valve opens on top of the device. After this, the air leaves the system, which prevents the formation of air locks.
Operating principle
There is a mesh inside the filter. This the element blocks the inlet, along which the coolant moves. During the passage of liquid through the mud filter, medium and large sized fractions are cut off. After this they move to the outlet. Thanks to this, relatively clean coolant flows to the radiators.
Advantages
Improved designs have the following advantages:
- Thanks to the flask, there is no need to remove the device to assess its degree of fullness. The assessment is carried out visually.
- A tap is fixed at the bottom of the device. Dirty water is drained through it.
- The filter removes air from the system, which prevents rust from occurring. This extends the life of the circuit.
Installation location and features
The installation location of the device depends on what heating system is it used for? For autonomous circuits, it is mounted at branch points, on the return before connecting to the boiler and on the bypasses.
Normal operation of the device guarantees correct installation. Before installing any device, the circuit is cleaned of dirt and rust.
There are special symbols on the mud pan that indicate the movement of liquid through the pipes.
The product is installed only in accordance with this guide.
If the mechanism is not fixed correctly, hydraulic resistance will arise inside the structure.
Attention! The mudguard provides the circular pump with protection against debris from penetrating the blades. If you refuse to use it or install it incorrectly, then the likelihood of engine and impeller failure will increase.
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Fine purification for water
Fine mud filter is additional filter, designed to remove small fractions.
Design
There are several designs of such a device:
- with metal mesh up to 5 microns-microns;
- with a cartridge made of fabric folded in several layers;
- with polymer porous filler;
- with mineral sorbent backfill.
Operating principle
The operating principle of such filters: water passes through the cassette and small fractions settle on its surface.
After this, the coolant moves through the pipeline without contamination. A fine mud filter cannot cope with large fractions, so it is not used as an independent filter. It's just the last stage of the cleaning system heating circuit.
Advantages
The main advantage of the filter is that it cleans the coolant from small particles of dirt. This increases the service life of the circuit, since the risk of corrosion is reduced.
Where and how is it installed?
Such a mud man installed on horizontal pipes. It is located between the taps to block the flow of water during maintenance.
Important! If the heating system does not use water, but antifreeze, then a fine filter cannot be installed, since such liquid does not pass through this device well.
The mud trap for fine cleaning is mounted on the pipe in the direction of water flow. There is no other way to install the filter.
Fine cleaning devices reduce the risk of an emergency.
Magnetic models of mud collectors
A magnetic filter for a heating system is a device made of two magnets with polar poles that are placed opposite each other. This device cleans the coolant not from pollution, but from metals.
Photo 2. Magnetic filter for cleaning heating systems from metals. Installed on a pipe.
Design
By design there are two types magnetic filters:
- Removable model. This device consists of two plates that are fixed on the pipe. The advantages of the device are that it is quickly replaced and easy to install.
- Non-removable mudguard. It is a pipe made from ferromagnetic alloys.
Operating principle
Opposite poles of a magnet attract metals present in the coolant. Once within the filter's coverage area, they settle on its surface.
Advantages
Advantages of a magnetic filter:
- the device slowly becomes dirty, so it is not cleaned for several years;
- prevents the formation of scale on pipes and radiators;
- increases the service life of the heating circuit by freeing the coolant from metals.
Installation rules
Device mounted only in front of the circulation pump. A place with the same cross-section of pipe and sump is selected.
Any heating system, no matter whether central or completely autonomous, is a rather complex “organism” that includes many elements, each of which fulfills one purpose or another. And in this list of components there must be a place for filtration and coolant purification devices. This function is assumed by mud collectors.
When designing central heating systems, such filters are mandatory, both in boiler houses or at thermal stations, and on collectors and elevator units directly in buildings connected to heating networks. But in individual construction, no, no, and there are situations when inexperienced home owners do not fully understand how important mud collectors are for heating systems, and do not include them in a independently developed scheme. And it’s completely in vain - these very inexpensive, easy-to-install and maintain devices can significantly improve the operation of the entire system, significantly extend the trouble-free period of its operation, relieve owners from the rather labor-intensive and dirty work of periodically cleaning pipes and radiators, and significantly reduce operating costs for heating housing.
Purpose of mud filters and advantages of their use
The carrier of thermal energy from the boiler or central line to the radiators is the coolant liquid. Most often, this role is played by water, pure or with some chemical additives. In certain conditions, for example, in private houses where the owners do not live all year round, special liquids that are resistant to negative temperatures are often used - antifreeze, but even in them water takes up a significant part of the total volume.
Water is always a very active oxidizing agent, causing corrosion of metal parts of heating routes, in-house wiring, radiators, shut-off and control valves. The resulting rust particles peel off from the walls over time and are picked up by the flow. However, if certain conditions are created in a pipe, on a tap, in a radiator, at a welded or threaded joint, in a tee or at a bend (narrow passage, unevenness, overflow from a weld, change in flow direction, etc.), then this the place with a high degree of probability becomes vulnerable to the formation of a plug - small particles of scale settle, accumulate, layer, narrowing, and sometimes completely blocking the passage of the coolant.
Many people are probably familiar with the situation when heating radiators heat up unevenly, not over their entire area. It also happens that several sections of the battery generally remain cold - the coolant clearly does not circulate through them.
If the check shows that there is no air in the radiator, then such a picture can only be caused by the accumulation of dirt.
Sometimes when opening the battery you can see a similar “sad” picture Such radiators will not be able to provide the required heat transfer, and you will have to resort to emergency measures - remove them and thoroughly wash them. And this, believe me, is a very complex and time-consuming process.
How are heating radiators flushed?
There are several technologies for cleaning pipes and radiators from accumulations of dirt and scale deposits. Details about how it is performed, the idea and its verification method are described in a special publication on our portal.
Not only radiators become overgrown with dirt - it also clogs pipe channels, taps, air valves, expansion tank pipes, etc. As a result, the operation of the heating system begins to completely go out of balance.
Clogged pipes are an additional, completely unnecessary load on the pump and boiler, unnecessary energy costs Thus, narrowed passages do not provide the required volume of coolant circulation, and in order to achieve the desired temperature it is necessary to increase the current power of the boiler. Moreover, the layer of plaque on the walls of pipes and radiators becomes a “thermal insulating gasket”, that is, heat transfer is sharply reduced. And this is another reason for increasing heating costs.
This “migrating” dirt and solid particles can lead to additional load on the circulation pump, damage to its turbine and complete failure. Well, the saddest thing will be if blockages form in the boiler heat exchanger - this in most cases leads to burnout of the heat exchanger, often leading to the replacement of all expensive equipment as a whole.
An increased concentration of solid inclusions can seriously change the electrolytic characteristics of the coolant, which is extremely undesirable for heating systems operating from an electrode (ion) boiler.
Electrode boilers require special coolant properties
The operating principle of electrode boilers is fundamentally different from other heaters. More details about the device and characteristics can be found in a special publication on our portal.
Unfortunately, it is not possible to completely eliminate the formation of solid suspensions in the circuits and heat exchange devices of the heating system. This means that it is necessary to organize a “collection point” in which debris and dirt will be retained, filtered out of the liquid, and then regularly removed, using very accessible methods that do not require dismantling any components of the heating system. This is precisely the main function of mud filters.
Equipping the system with such filtering devices immediately provides a number of advantages:
- The most complex and expensive components of the system - the pump and the boiler - receive reliable protection from contamination, channel clogging and damage. Consequently, their service life increases significantly.
- There is no need to frequently drain the coolant to replace it with a new, clean one - it will already be maintained in a condition satisfactory for use. Considering that some coolants cost quite a lot, this is another significant saving.
- The use of filters and high-quality, correctly selected coolant will free owners for a long time from the procedure of cleaning and flushing all heating systems.
Much depends on the quality of the coolant
Of course, maximum efficiency and operational safety of a heating system can only be achieved by using high-quality coolant. A special publication on our portal is entirely devoted to varieties and characteristics.
- Heating radiators that are free from dirt and solid deposits provide maximum heat transfer, and free channels of pipes, fittings, connecting units and control valves provide minimal hydraulic resistance to the coolant. Both allow the boiler and pump to operate optimally with minimal consumption of the corresponding energy carriers. Moreover, it is estimated that in general the saving effect of operating a “clean” system, compared to one with mud deposits, can reach even 40%.
In a word, there is something to think about - installing a relatively inexpensive and easy-to-use device immediately gives owners a lot of preferences.
Main types of mud filters and their design
General classification of mechanical cleaning filters
Filters for rough mechanical purification of water from solid impurities (which deserve the name mud filters) use three basic principles for separating suspended matter:
- Settling filters use gravitational forces - due to a sharp increase in volume and, accordingly, a drop in flow rate, solid particles settle to the bottom under the influence of gravity. Often this is complemented by a sharp change in the direction of movement - then turbulent and centrifugal forces are also included in the “work”, carrying more inert heavy particles to the periphery of the flow, where they settle, thereby releasing water.
A typical structure of such a mud trap is shown in the diagram below:
Usually this is a vertically located cylindrical body (item 1), into which two pipes with flange connections are welded: inlet (item 2) and outlet (item 3). The bottom of the body is closed with a flange plug (item 4), the top is welded tightly. The bottom plug usually has a pipe (item 5) for installing a tap to it for carrying out maintenance work - draining sludge and washing the filter. There is also a pipe on top (item 6) - a valve is installed here to release air when the system is filled with coolant.
In the cavity of the central cylinder there may be one or more jumpers (item 7) that sharply change the direction of the flow of water passing through the filter (shown by blue arrows). Solid inclusions (pos. 8) settle down, where a layer of sludge is formed (pos. 9), which is regularly cleaned during maintenance.
Such filters are usually installed on large pipelines, for example, in industrial plants. In a home heating system, their use is not very rational. However, the principle of gravitational water purification is successfully used in other filter models.
- Mesh filters - in them, the water flow is passed through a mesh structure with cells of a certain size. All particles whose diameter exceeds the mesh size remain in the filter.
- Magnetic filters, as the name suggests, contain permanent magnets that attract small particles of metal and metal scale. It is recognized that installing a magnetic filter, in addition, sharply reduces the likelihood of scale formation on the walls of pipes and in the heat exchangers of heating devices.
As already mentioned, very often in modern mud filters used for heating systems, two, and sometimes all three, principles of mechanical water purification are combined.
Depending on the type of installation in the system, mud filters can be of three different designs:
- On pipes of small and medium diameter, typical for autonomous heating systems, sleeve filters are often installed.
On both sides of such a product for connection to pipes there are couplings with internal (there are models with external) threads. Accordingly, hexagons are provided on the filter housing for inserting an open-end, adjustable or gas wrench during installation or dismantling. Such filters are usually immediately “packed” into the system when it is assembled.
- It is extremely difficult to work with threaded connections on medium- and large-diameter pipes (over 2 inches), so filters with flange connections are most often installed in such areas.
A flange connection involves installing an O-ring, and then tightening it with bolts. When initially installing such a filter, there are somewhat more concerns, since it is necessary to weld the counter flanges onto the pipe in a strictly established position while maintaining the installation length of the product. But if you need to remove the filter, this will be quite simple to do, without resorting to dismantling an entire section of wiring.
- There are filters that are mounted “tightly” to the pipes - such devices have pipes on both sides, along the edge of which there is a chamfer - for the weld.
Probably the only advantage of such filters is their lower cost. But in case of an accident or the need for replacement, you will have to cut out a section of the pipe.
Non-removable, welded mud traps also include filters in a polypropylene casing - specially designed for small-diameter pipes of similar design.
They are also welded immediately during installation of the pipework, and to replace them, if necessary, you will have to cut out an entire section. Therefore, they are probably not particularly popular - usually most craftsmen prefer to install metal couplings, and only then switch from them to polypropylene.
According to the method of maintenance, filters also have their own gradation:
- Self-flushing - in such mud tanks there is a tap in the lower part, when opened, the accumulated dirt (sludge) is washed out with a stream of water. At the same time, the filter mesh is cleaned.
For better cleaning of the mesh, a bypass filter with a valve is often provided when installing the filter. This makes it possible to redirect the flow of water from the reverse side during maintenance - even solid inclusions tightly stuck in the cells are washed out very well and drained into the drain tap.
- Wash filters. They do not require dismantling the entire product - after disconnecting a section of the system from the coolant supply, it is enough to unscrew the plug or remove the flange plug, remove the filter element and clean and rinse it (if necessary, or in models with cartridge inserts, replace it with a new one). Then the filter is assembled in the reverse order - and it is ready for use again.
- There is also a category of non-washable mud filters. To service them, you have to completely dismantle the entire device from the system. Of course, this is very inconvenient, and such products are not in demand and are practically not installed in autonomous heating systems.
And finally, mechanical filtration devices can be divided into two categories according to the degree of purification of the liquid passing through them:
- , which, in principle, are called “mud collectors”, have meshes capable of retaining solid inclusions larger than 300 microns (0.3 mm).
- Fine cleaning devices are designed to filter out suspended matter ranging in size from 5 to 300 microns. They are usually used in post-treatment systems for tap water for domestic and food needs. Such filters are not used in a heating system - such high cleaning is not required here, and the filter elements themselves will quickly become clogged and require replacement or washing.
Now let's look at the most common types of mud filters that are installed in heating systems.
Brass mesh “oblique” filters
This is perhaps the most common category of mud filters used in local home heating systems. They have a coupling threaded connection in a fairly wide range of sizes - from ½ to 2 inches, which is quite sufficient for installation on any autonomous heating pipeline.
The design of the filter is quite simple:
The device of a brass “oblique” mud filter The cast brass body (item 1) is a monolithic pairing of two cylinders, straight and inclined (item 3). On both sides of the straight cylinder there are threaded couplings for mounting the filter (item 2). The “oblique” cylinder ends with a brass plug (item 4) with a hex key. A sealing gasket is placed between the plug and the body, usually Teflon (item 5). In the most inclined part there is a filter element - a stainless steel mesh (item 6) with cells of a certain size.
An arrow on the housing must indicate the correct direction of flow of the filtered liquid. The beveled part always faces forward in the direction of flow.
The tables below present the main operational and installation parameters of brass “oblique” filters:
Main performance characteristics of brass “oblique” filters:
| Product parameters | Pipe diameter | |||||
|---|---|---|---|---|---|---|
| G½ | G¾ | G 1 | G 1¼ | G 1½ | G 2 | |
| Nominal pressure in the system, bar | 20 | 20 | 20 | 16 | 16 | 16 |
| Crimping pressure, bar | 30 | 30 | 30 | 24 | 24 | 24 |
| Mesh cell size, microns | 500 | 500 | 500 | 800 | 800 | 1000 |
| Distance between the centers of grid cells, mm | 1,1 | 1,1 | 1,1 | 1,4 | 1,4 | 1,6 |
| Density of mesh cells per 1 cm², pcs. | 156 | 156 | 156 | 83 | 83 | 59 |
| Maximum permissible coolant temperature, °C | +150 | |||||
| Degree of transparency (“transparency”) of the filter, % | 39 | 39 | 39 | 53 | 53 | 59 |
| Total filtration surface area with clean mesh, cm² | 17,9 | 32,6 | 44,8 | 55,7 | 77,1 | 111,0 |
| Average throughput of the device with a clean filter element, m³/hour | 3,15 | 5,0 | 9,9 | 15,5 | 24,0 | 28,5 |
| Nominal coolant flow with a clean filter, m³/hour | 1,41 | 2,24 | 4,43 | 6,93 | 10,7 | 12,7 |
| Average filter life | up to 30 years old | |||||
Installation characteristics of filters:
| Conditional bore, DN, mm | Pipe thread diameter | Construction dimensions | Empty weight, kg | |
|---|---|---|---|---|
| height H, mm | length L, mm | |||
| 15 | G½ | 40.5 | 51 | 0.132 |
| 20 | G¾ | 47.5 | 63.5 | 0.213 |
| 25 | G 1 | 53 | 68 | 0.285 |
| 32 | G 1¼ | 65 | 91.5 | 0.573 |
| 40 | G 1½ | 73 | 102.5 | 0.750 |
| 50 | G 2 | 88 | 126 | 1.160 |
Installation of such filters is not particularly difficult for those who are familiar with the basics of plumbing techniques. Typically, a shut-off valve is installed in front of the filter - it allows you to shut off the coolant supply to carry out preventive work to clean the device from accumulated dirt. But the main thing that is important to consider is the correct orientation of the filter in space:
| Correct installation | Incorrect installation | ||
|---|---|---|---|
 | Correct installation on a horizontal area. The beveled cylinder is located at the bottom. |  | Quite often, would-be “masters” install the filter with the plug facing up, apparently for reasons that it is easier to get to it during maintenance. However, such placement leads to a very rapid contamination of the passage into the filter chamber with dirt, reducing the throughput of the device |
| Correct installation in a vertical area. The coolant flow is organized from top to bottom. | Such an arrangement in a vertical section with coolant flows upward does not allow filtered sludge to concentrate in the cleaning chamber for preventive maintenance. The cleaning capabilities of the device are sharply reduced, and dirt can accumulate on the walls of pipes or on shut-off valves. | ||
The filter is usually installed on the return pipe in front of the circulation pump or boiler, if the pump is structurally part of the boiler. Thus, all possible contaminants collected along the heating circuit are removed from the coolant, which has described the full circulation cycle.
Regular cleaning of the “oblique” filter is not particularly difficult. You just need to turn off the coolant supply taps on both sides (if a check valve is installed behind the filter along the flow of liquid, then you can only close it from the inlet side). Then a container is supplied from below to collect the leaking liquid and accumulated sludge. The plug is unscrewed with a wrench and the mesh is removed.
The mesh of the “oblique” mud collector, tightly clogged with sludge The mesh should be cleaned with a polymer brush and then rinsed thoroughly with strong water pressure. The glass of the “oblique” cylinder itself is checked - there should also be no deposits left there. Then reassembly is performed by tightening the plug. At the same time, you can evaluate the condition of the sealing gasket, since over time it may require replacement.
Video: device and cleaning process of the “oblique” filter
You should be careful when purchasing such a filter. All the advantages mentioned in the table are valid only for high-quality brass products (some may have an external shiny nickel-plated or oxidized coating). Unfortunately, there are a lot of cheap fakes on the market made from silumin alloys, and no one can guarantee the long-term operation of such a filter.
Cast iron “oblique” magnetic filters
Externally, such filters are very similar to the brass filters discussed above and, in general, are similar to their design. The difference is in the material of manufacture: the body and plug are cast from cast iron. The filter element is the same cylindrical mesh made of stainless steel. The gasket between the plug and the body is usually paronite.
Cast iron “oblique” mud pan with a magnetic block However, the filtering unit is supplemented with one more element. A stand is rigidly mounted along the axis of the plug, on which disk-shaped permanent magnets made of corrosion-resistant material are located at certain intervals. Thus, filtration takes place in two directions - the mesh catches mechanical impurities, and the magnetic block catches metal particles and scale. The quality of coolant cleaning only benefits from this.
Main characteristics of manufactured cast iron “oblique” magnetic filters:
| Conditional bore, DN, mm | Pipe thread diameter | Construction height, mm | Construction length, mm | Socket wrench size, S, mm | Metal mesh cell size, mm | ||
|---|---|---|---|---|---|---|---|
| N | H1 | L | L1 | ||||
| 25 | G 1 | 80 | 140 | 120 | 200 | 32 | 1.2x1.2 |
| 32 | G 1¼ | 100 | 155 | 140 | 220 | 46 | 1.4x1.4 |
| 40 | G 1½ | 110 | 180 | 160 | 280 | 46 | |
Please note that in the mounting dimensions columns two values of length and height are indicated. L and H are the usual installation values, and L1 and H1 - taking into account the mandatory leaving of the necessary space for free removal of the plug with stand and magnets during maintenance work.
Otherwise, the procedure for installing such filters in the system and the cleaning process do not differ from similar operations with “oblique” brass ones. In this case, the rack with magnetic disks is also cleaned and washed.
Flanged magnetic dirt filters
Such filters almost completely repeat the principle of operation of cast iron “oblique” filters - the only difference is in size. On pipes from G 2 and above, flanged devices are usually installed.
Instead of a threaded plug, there is also a flange type plug. There is often a place for a drain hole, closed with a plug, which allows you to drain the sludge and flush it from time to time without having to remove the entire plug.
Characteristics of flange magnetic filters
| Conditional bore, DN, mm | Construction dimensions of products | Flange bolt hole diameter, d, mm | Number of bolt holes on the flange, n, pcs. | Mesh cell size, mm | |||
|---|---|---|---|---|---|---|---|
| height, mm | length, mm | ||||||
| N | H1 | L | L1 | ||||
| 50 | 140 | 200 | 230 | 280 | 18 | 4 | 1.4x1.4 |
| 65 | 165 | 250 | 290 | 355 | 18 | 4 | |
| 80 | 195 | 275 | 310 | 385 | 18 | 8 | |
| 100 | 215 | 315 | 350 | 425 | 18 | 8 | |
| 150 | 320 | 490 | 480 | 645 | 22 | 8 | 2x2 |
| 200 | 415 | 630 | 650 | 890 | 22 | 12 | |
When installing such filters, the installation length and height (L and H), and operational length (L1 and H1) are also taken into account - taking into account the place for removing the plug and removing the mesh and magnetic block.
Subscriber filters, mud-settlers
Among the most common filters installed on heating mains, in particular, in areas where they are connected to intra-house networks, are the so-called subscriber filters. They can be produced in vertical or horizontal versions, but vertical is much more common. Such devices combine the functions of a sump and mesh filtering of the liquid passed through them.
Such mud filters are called “subscriber filters.” Such devices have a very long service life, are easy to maintain, and their large internal volume allows you to reduce the frequency of regular maintenance.
Structurally, they are a cylindrical body made of steel pipe (item 1). Nozzles with a flange are welded into it on both sides - inlet (item 2) and outlet (item 3). The nominal diameter of the nozzles corresponds to the pipe into which the filter fits.
The exhaust pipe has a special design. Its length reaches approximately the central axis of the cylindrical body, and is plugged from the inside. In the segment from the wall to the plug, holes with a diameter of 5 to 8 mm are drilled in its walls, so that their total area is no less than twice the cross-sectional area of the pipe. A filter mesh (item 3) with cells of the appropriate size is placed on top of these holes.
A flange is welded along the lower edge of the pipe body, to which the bottom plug is bolted (item 5). Typically, the plug provides the ability to install a drain valve (item 6) for regular cleaning of the cavity from accumulated dirt.
The filter cover is tightly welded, but it has a pipe or hole for mounting an air vent valve (item 7).
Characteristics of the line of vertical subscriber mud filters
| Conditional bore, DN, mm | Mounting dimensions | Empty weight, kg | |
|---|---|---|---|
| height H, mm | length L, mm | ||
| 40 | 217 | 308 | 16.7 |
| 50 | 240 | 359 | 22.7 |
| 65 | 369 | 419 | 45 |
| 80 | 369 | 419 | 48.9 |
| 100 | 421 | 473 | 70 |
| 125 | 421 | 473 | 73 |
| 150 | 563 | 526 | 103.3 |
| 200 | 669 | 626 | 184 |
| 250 | 785 | 730 | 269 |
The coolant, passing through such a filter, goes through two stages of cleaning. Large and medium-sized particles precipitate under the influence of gravitational and centrifugal forces, while smaller ones are already retained on the mesh.
Due to the simplicity and reliability of the design, relatively low production cost, and high operational potential, such subscriber filters are widely used in in-house wiring of heating systems. In particular, they are a mandatory element of the elevator unit.
What is an elevator unit of a heating system?
The temperature and operating pressure of the coolant coming from the heating mains must be brought to certain values that correspond to the capabilities and needs of a specific in-house heating system. One of the simplest and most reliable solutions is installation, the design and operating principle of which is described in a special publication on our portal.
Self-cleaning dirt filter with additional air vent function
And at the end of the publication - an overview of another type of filter. These are modern self-cleaning devices in a compact vertical housing that will not take up much space and will ensure high-quality cleaning of the coolant from impurities.
Moreover, some models are equipped with an additional option - they allow you to separate (separate) dissolved gases and automatically remove them, preventing the well-known “scourge” of any heating system – its “airing”, that is, the formation of air pockets.
One of these filters is shown in the diagram:
Typically, the housing of such a filter is a metal cylinder (item 1), with a coupling connection to the inlet (item 2) and outlet (item 3) pipes. A glass (pos. 6) is screwed to the bottom for collecting sludge (pos. 7) - it can also be metal or plastic, including, on some models, transparent, which allows visual monitoring of the condition of the filter. At the bottom, the glass ends with a tap (item 8) for cleaning and rinsing the device.
There are grids installed inside the central part of the body. One of them, the outer, larger one (item 4), acts as a separator of air and other gases dissolved in water. Bubbles accumulate and grow on it, which then, when they reach a certain size, independently rise upward under the influence of gravity.
An internal mesh with small cells (item 5) is used to filter solid particles from the coolant.
A block for collecting separated air (item 9) with an automatic air removal system is screwed onto the top of the housing. The valve design includes a float (item 10) connected by an actuator lever (item 11) to a needle valve (item 12). As air accumulates in the block, the float drops lower and lower, and when it reaches a certain level, it opens the needle valve through a lever. The air exits through the holes in the cover (item 13), the float rises again, and the valve closes.
The procedure for cleaning such filters from sludge has already been mentioned in the publication - just open the tap from below and wash out the dirt with a stream of water. It’s even better if it is possible to create a reverse flow of liquid for cleaning.
Some filters of this type are additionally equipped with magnetic inserts, which increases cleaning efficiency. In addition, many models have built-in pressure gauges that indicate the fluid pressure at the inlet and outlet of the filter. A simple comparison of the readings of these devices can give a very clear picture of the degree to which the filter elements are clogged with sludge (with a clean filter, the readings should be approximately equal), that is, signal the need for preventive maintenance.