Overall dimensions of the split system 7 indoor unit. All about the outdoor unit of the air conditioner. Finished Size Examples

Korean company Samsung produces air conditioners various types. A significant part of the production is occupied by split systems, also on the market under this brand there are both monoblock window models and multi-split systems.

All modern systems this brand's air conditioners are distinguished by:

• multifunctionality;
• energy efficiency;
• low noise level;
• stylish design;
• efficient system air filtration.

The multi-stage cleaning system not only cleans the air stream from contaminants, but also disinfects it, killing bacteria and microorganisms.

Compact windows

The smallest ducts have a block height of 199 mm. These are the so-called low-profile channel-type units, which are produced to work in powerful multi-zone systems.

Ordinary duct air conditioner designed to work in a room of 40 sq. m, like the ADH1800E model, has the corresponding power (5 kW) dimensions 1340x260x600 mm.

During operation household split-systems you can feel bad smell rot along with air currents from the device. It indicates the need for preventive cleaning of the unit. In addition to repulsive amber, clogging of nodes can cause rapid wear of the power unit, increased power consumption and the occurrence of allergic reactions in a person.

This procedure can be entrusted to an employee service center. But if you have been using a split system for a long time, you can handle the work yourself, saving money. It is only necessary to familiarize yourself with the procedure for disassembly and preventive cleaning.

Indoor unit dimensions

Before installing the indoor unit of the air conditioner, you should take an interest in its dimensions. This is especially important when renovating modern technologies quite often provide for the installation of suspended ceiling systems, which can affect the height of the ceiling, as well as the parameters of the described device.

On sale you can find non-standard models that have unique sizes. The length of the block usually varies from 700 to 800 mm. Products up to 900 mm are somewhat less common. Experts recommend taking into account an average length of 770 mm.

As for the height, it is usually equal to 250-290 mm. The average value is 270 mm. Depth is not of great interest to consumers, but it reaches 240 mm. Minimum value equivalent to 170 mm. From this we can conclude that the average dimensions of the indoor unit of the air conditioner are 770 x 270 mm.

Knowing these parameters allows you to determine at what distance from the ceiling and walls to hang equipment. Controversy over this issue great multitude. In some instructions, the minimum distance is 50 mm, while in others it goes up to 300 mm. The optimal value is equal to a figure from 60 to 150 mm.

Specialists usually install air conditioning with a distance of 100 mm. Before installing the indoor unit of the air conditioner, it is important to consider whether there will be curtains in the room. The step between them and the split system is usually 150 mm. You can increase this value up to 250 mm. The average distance from the block to the wall is 400 mm.

Classification of indoor units

In order to carry out disassembly, it is necessary to determine the type of the indoor unit of the air conditioner, which can be represented:

• wall split system;
• channel air conditioner;
• cassette device.

The most common are wall-mounted models, which are more affordable and are sometimes also called household ones. Their installation can be carried out in a room for any purpose, and the power within 7 kW allows you to cool up to 70 m2 of area. Such blocks are usually installed in the upper part of the wall, not far from the window, since the design provides for the presence of an outdoor unit, and the nodes must be interconnected.

Wall-mounted air conditioners are not capable of supplying fresh air to the premises, as this requires separate system ventilation. If you wondered how to disassemble the indoor unit of the air conditioner, you can read this information below. It is for such a device that the recommendations in the article are given.

In addition to household air conditioners, some manufacturers supply semi-industrial devices to the market, the power of which reaches 10 kW. Outwardly, they look like traditional split systems, but in terms of parameters they are semi-industrial equipment.

Ducted air conditioners are installed with suspended ceilings that hide them completely. The distribution of cooled air is provided by heat-insulated air ducts, which are located in the interceiling space. Such structures can cool several rooms at once. The power of the equipment reaches 25 kW, which makes it possible to provide cooling for a cottage or several rooms of an apartment. As a main feature channel systems the possibility of filing fresh air in the volume that is guaranteed by the functioning of full ventilation.

Cassette air conditioners require a false ceiling during installation. When compared to duct designs, cassettes distribute cooled air through the bottom of the unit. She closes decorative grille and usually has the following dimensions: 600 x 600 and 1200 x 600 mm.

Dismantling and cleaning the air conditioner

To clean the indoor unit of the air conditioner, it is necessary to disassemble it. For this, screwdrivers are prepared different configuration and sizes. You should take care of the presence of a box for collecting fasteners. Requires electrical and functional diagram device. On some models, they are printed on inside top cover.

To clean the internal elements you will need:

• clean rag;
• detergent;
• a vacuum cleaner.

The first step is to de-energize the air conditioner. This is in accordance with electrical safety regulations. Remove the plug from the socket. Top cover block is removed. Bolts are unscrewed, which can be two or three. Usually they are closed with decorative caps. The top cover of the indoor unit is removed. If it is covered with a layer of mold and dirt, it should be washed in the bathroom with detergents and brushes.

When disassembling the indoor unit of the air conditioner, you will need to remove air filters. They are made of plastic and are designed for rough air purification. Sometimes they are fixed on the lid or inside the air conditioner. The filters are washed under an intense stream of water. A brush will help with this.

The airflow guides should also be removed. Blinds are removed from the grooves. To facilitate the process, you need to slightly bend them. These elements direct the flow of cold air into the room and also need enhanced flushing.

Removing the bottom cover

The next step is to remove the bottom cover. Will need to extract drainage tube and power wire. In the process of this, three latches should be pressed and the drain tray together with the outlet hose should be disconnected from the unit.

Removing terminal blocks

The indoor unit of the air conditioner has terminal blocks. They are disconnected during disassembly, and then the electronic control unit and transformer are removed. In order to remove the first one, it is necessary to press side mounts, and then pull the device towards you. Before this, the ground wires are unscrewed.

Removing the fan motor

The fan motor can now be removed. To do this, the bolts are unscrewed, which are strengthened to the chassis. The evaporator is raised and the engine is pulled out along with the rotary fan. The motor must be separated from the fan, but first you have to warm up the bolt head with a soldering iron. This will unlock the thermal lock on the motor pulley. Once the fan blades can be removed, they must be washed. Assembly is carried out in the reverse order.

Cleaning the outdoor unit

Outdoor and indoor units of air conditioners are equally in need of maintenance. The frequency for the first is twice a year, which is true even with intensive use. A vacuum cleaner is required for this, but the device must be powerful enough to pull dust from external filters and heat exchange radiators.

On your own or with the help of specialists

If the unit is located at an impressive height, then you can unscrew the protective grille and vacuum it, as well as wipe the insides from dust. Otherwise, you can seek help from professionals who will remove the air conditioner using climbing equipment or a tower. Cleaning yourself can be done using compact senders, but the air conditioning system will have to be de-energized and turned on only 30 minutes after the end of the service.

Finally

During the operation of the split system, dust settles on the fan impeller, where a “fur coat” of dirt is formed. This prevents the passage of air flow when blowing the evaporator. The latter freezes over, and the user does not receive normal cold and intense air flow.

Cleaning the fan of the indoor unit of the air conditioner is also required when you see black flakes flying out of the appliance. This suggests that the amount of dirt is so large that it does not hold onto the internal nodes. As a preventive measure, from time to time you can dismantle the fan and wash it. chemicals. But not all models make it easy to extract this part of the system.

For air conditioning and administrative buildings install split systems various kinds and types. A split system is a device consisting of two blocks: outdoor and indoor. The first is taken out into the street, the second is mounted in the room. Both modules are interconnected copper pipeline through which the working gas (freon) circulates, and electrical communications.

Types of split systems and types of indoor units

View is a more general concept applicable to technical devices climate control regarding their purpose for certain buildings. The type has a narrow semantic focus, which means any feature of the design or design.

Split systems are subdivided both by type and by type. There are two types of two-component installations: domestic and commercial or semi-industrial. The former are mounted in apartments or small offices, the latter in shops, hairdressers and other similar establishments.

All split systems are divided into types regarding the design and design of the indoor unit:

• wall;
• cassette;
• columned;
• channel;
• floor and ceiling.

Each manufacturer produces split systems with different types of indoor units, completing them with certain functions and a standard set of operating modes, which include cooling and ventilation of the air in the room. It is the parameters of this part of the system that justify the choice of buyers.

Regardless of the dimensions and external design, any room unit consists of:

• heat exchanger (evaporator);
• fan;
• air distribution grille;
• input filter;
• guide blinds;
• front panel;
• LEDs;
• temperature sensors.

Fine filters, winter set and others additional elements come as an option at the request of the customer. May include a circuit board if the unit has wall-mounted. Operation parameters are set from the remote control. Some models of expensive equipment have the ability to control functionality via the Internet, from a phone or from a central controller.

The principle of operation of the indoor unit of the air conditioner

In general, cooling looks like this: in order to absorb heat from the room and release coolness, the indoor unit fan draws in heated air from the room, after which the process of heat absorption by the refrigerant begins when it passes through the cold coil.

The refrigerant is a liquid gas (freon), due to which the air cools. In fact, it is a heat carrier. In the process of transferring cold to the air and taking heat from it, it changes its state, that is, it evaporates. This happens in the heat exchanger of the indoor unit. Here from liquid state freon turns into gaseous. He took away the heat, the air cooled and enters through the fan back into the room. heat dissipation process already underway through the outdoor unit.

In simpler terms, the role of the indoor module is to take in warm air, cool it and return it to the room. When the device is used for heating, on the contrary, it becomes a conductor of heat, changing its functions with the outdoor module. All types of indoor units work according to this principle.

Indoor wall-mounted units and their dimensions

wall-mounted indoor unit

Household air conditioners include wall-mounted models - the most popular among buyers. They resemble a rectangle or square in shape, like the LG ART COOL GALLERY wall-mounted appliances. They are hung on the wall in a place convenient for the user, so that the treated air does not go to the permanent residence of a person.

Pick up required size the indoor unit of the air conditioner relative to the capacity of the room. Each manufacturer has a line of large, standard and even reduced climate control devices.

The concept of the size of the indoor unit of the air conditioner includes such quantities as:

• height;
• width;
• depth.

The minimum height can be about 24-25 cm, width - 70-74 cm, and depth - 18-19 cm. For example, the company produces a series wall splits with a depth of the indoor unit of only 18 cm, which greatly expands the possibilities of installing such a device at various points in the room.

The maximum height of the wall-mounted room unit can be up to 30-32 cm, width - 110-120 cm, and depth - about 30 cm. For example, MITSUBISHI ELECTRIC produces a series inverter splits with exactly these settings.

If the indoor unit of the air conditioner has a non-standard design, for example, it is supposed to be located vertically in the room, then these parameters can vary greatly.

As a rule, air conditioners, and not only wall-mounted ones, have a direct dependence of the dimensions of the indoor unit on its internal device, or rather, on the size of the heat exchanger and the space for air blowing it. The smaller they are, the smaller the device, and the worse the performance.

Some manufacturers maintain normal performance while downsizing by increasing the fan speed, but new flaw- increased noise. This is of paramount importance when choosing an air conditioner in an apartment. You can avoid this trouble by lowering the air flow. Although in any case a very powerful split cannot have a small internal module.

Today, some manufacturers have turned their attention to the production of non-standard room modules for splits. wall type. For example, LG in the ARTCOOL series offers square devices with the ability to change the picture on the case, and surprised everyone with the release of a vertical indoor air conditioner unit with non-standard air distribution in two directions, which is more typical of floor-to-ceiling models. GREE has been offering corner appliances for several years now, but it is difficult to find them in Russia.

As a rule, both the vertical indoor unit of the air conditioner, and the corner, and the square buyers prefer either because of space savings, or purely from design preferences.

Semi-industrial air conditioners and their dimensions

The remaining types of the indoor unit of the air conditioner are classified as semi-industrial equipment, but low-power models of such devices can also be installed in ordinary apartments.

The cassette has square shapes and fits easily into a cell false ceiling. Its dimensions can be 600x600 mm or 800x800 mm, although some manufacturers produce a series of super compact cassettes with dimensions of 500x500 mm.

Along with cassette indoor modules, duct devices, which are a hybrid, are sewn into a false ceiling (or wall). air handling unit and air conditioner. They not only cool the room, but also can freely update room air by mixing the street with the help of additional equipment - a supply unit. In both types of these climate control units, only distribution grilles are visible from the outside.

The only drawback is that they require a ceiling space of at least 30 cm for installation.

Column air conditioners look like an elongated cabinet. They are placed in large rooms on the floor where a large cooling capacity is required. Their dimensions are much larger than any wall-mounted model, but this is a necessity, since it is impossible to achieve such power in another way.

Floor-ceiling splits are quite compact and at the same time quite productive for rooms up to 100-120 m². Their inner block is shaped like modern radiator. They are easy to care for and use. The main advantage is that there are two ways to mount such an indoor unit: to the wall and on the ceiling. If the module is hung on the wall just above the floor, then the airflow goes in two directions, capturing even the most difficult and hard-to-reach areas of the room. That is why floor and ceiling models like to be mounted in rooms with a complex configuration.

Air Conditioner Specifications

Not only design, but also specifications the indoor unit of the air conditioner determine the purchase of a particular system. Indeed, depending on how correctly they were selected, the device will either work properly or quickly use up the inherent potential.

What are the main technical characteristics that are important when choosing the indoor unit of an air conditioner in a room? We look at the example of the LG air conditioner series ART COOL GALLERY.

For each manufacturer, these data can be supplemented with other parameters, so the technical characteristics of the indoor unit of the air conditioner are usually looked at either on the nameplate or in the user manual.

Conclusion: any room unit is endowed with cooling and heating power (kW), power consumption of electricity (kW), air flow (m³ / h), as well as certain dimensions and weight.

With the power consumption, the issue is a little complicated by the fact that it may not be indicated specifically for the indoor unit. More often in the characteristics they write consumption parameters in general for a split system, while it consumes much less than an outdoor device - an average of 100-200 watts.

Features of installing an air conditioner

Mounting a wall-mounted room module can be very diverse. Most often, the block is fixed to the right or left of the window and as close to the outside as possible so that the length of the route does not exceed the recommended length of 5 meters. If, if necessary, these values ​​are increased, then the line is sewn into a strobe in the wall or neatly placed in a decorative plastic box along with the rest of the connecting communications.

Other types of indoor units are mounted in the places provided for them:

• channel- in suspended structure the ceiling of the room or, to avoid noise, in non-residential premises - in the pantry, corridor, restroom;
• cassette- in the suspended ceiling structure so that the airflow from the grate does not go to the places where people stay, but to the unused area;
• floor-ceiling- on a wall 15-20 cm from the floor or on the ceiling in a place where air will diverge over the entire surface;
• columnar- on a flat solid floor.

The indoor unit should not be exposed to direct sunlight, and any exposure to heat sources is also excluded.

The indoor unit of the air conditioner on the loggia

Sometimes a customer may require the installation of an indoor unit of an air conditioner on a loggia, explaining this by the fear of catching a cold, limited space in the room, unwillingness to ditch the wall or have a long track packed in a box. Another reason for such a request may be the inability to find an area in the room that the residents would not use. This happens when there is a large crowd of people in one room.

Is it possible to install an indoor unit of an air conditioner on a loggia, if so, what requirements should be taken into account?

• The ingress of warm air through the window and cracks under it is excluded. Glass curtains thick curtains, and the walls provide tightness;
• It is necessary to take out the door and window openings between the living area and the loggia so that the treated air circulates freely throughout the territory;
• They prefer inverter models so that under heavy load (and it will be necessary with this arrangement of the device), the compressor does not work in a constant start-stop mode;
• The cold power is taken with a good margin, since in order to reach 22 ° C in the room, it will be necessary to set 18 ° C on the loggia.

Even when the required conditions are met, problems occur regularly. Firstly, the temperature difference will still be felt. Simply put, there will be a north pole on the loggia, while the room will only get a little cooler. Secondly, the potential of even an inverter will still be used up much faster.

Competent experts will never advise installing an indoor unit from an air conditioner on a loggia, based on all of the above points.

Ways to fix the air conditioner to the wall or ceiling

Depending on the type of indoor unit, there are two types of mounting it to the wall or ceiling. Household split systems are hung on mounting plates. This happens according to the following scheme:

• holes are drilled in the wall;
• dowels are inserted into them;
• the mounting plate is screwed;
• air conditioner is hung on it.

Thus, the indoor unit is fixed to the wall only at wall models. Commercial modules are fixed with special studs according to a different scheme:

• mark the places of fastenings on the ceiling;
• drill holes;
• insert collet fasteners;
• studs are screwed into them;
• a block is hung on the studs;
• tighten nuts.

It is worth remembering that the installation of channel systems with air ducts is carried out at the stage of construction and repair work. Other splits can be installed at any time.

Schematic diagrams of the air conditioner

For the correct installation of the internal module, use the fundamental electrical circuits air conditioner, on which all interconnections and their connection points are indicated. It is impossible to carry out installation without them, since there is no single scheme, and for different types modules are completely different. The same goes for on/off and inverter splits.

For each manufacturer, the scheme of an indoor unit of the same type can vary greatly, therefore, only the one that is included in the manual by the manufacturer is used.

Service and diagnostics of malfunctions of the air conditioner

Each split system needs regular maintenance, which involves cleaning the units from external and internal contamination, as well as diagnosing malfunctions and refilling with freon if necessary.

Is it possible to somehow clean the indoor unit of the air conditioner at home? Yes, this is real, but undesirable, since an inexperienced user can damage any part of the device. If, nevertheless, it is not possible to call the master, then the person should know how to disassemble the indoor unit of the air conditioner in order to wash the filters, fan and heat exchanger.

Take off first decorative panel, to do this, press the latches on the sides, and the case cover easily moves away. Then carefully remove the filters, fan, condensate collection tray and rinse them under running water. running water. The heat exchanger is wiped with a damp cloth, as it is a stationary part. After cleaning, all elements are wiped dry and reinstalled.

At the end of the article, you can watch a video on how to disassemble the indoor unit of an air conditioner and how to clean it without the help of specialists.

To carry out these steps, you will need a soft microfiber cloth and a special foam for cleaning split systems.

Even if there are no problems with how to clean and disassemble the indoor unit of the air conditioner, the user himself will not be able to refuel and diagnose, so you will have to call specialists who have professional equipment and materials.

In what cases may you still need the help of a master? The user should be alerted to such points as:

• poor cooling;
• unusual noises and vibrations;
• block freezing;
• inability to turn on the air conditioner;
• leaving the device in the mode of fault codes.

Many users are interested in why the indoor unit of the air conditioner freezes over, and how serious it is. This sign indicates that:

• there is not enough freon in the split system;
• there was severe contamination of some working units and filters;
• the device is used at an unacceptable temperature.

By measuring the working pressure, the master will immediately determine if there is actually not enough freon in the system. polluted internal elements You can see it for yourself by removing the case cover. Also, the cause of freezing of the indoor unit of the air conditioner can be a too long route, which the installers simply did not refuel during installation.

If any deviations are noticed in the operation of a split system of any type, it is necessary to immediately invite a specialist.

Air conditioning has become a habit household appliance. Of the variety of air cooling devices, the most popular are split systems consisting of two units-blocks, one of which is installed outside the room, and the other is inside. Air conditioner indoor unit complex device, which takes warm air out of the room and sent back chilled.

Any air conditioner functions due to the properties of liquids to release thermal energy when liquid is released and absorb heat when it evaporates.

The indoor unit is always placed indoors (usually mounted on a wall or ceiling), and the outdoor unit is taken out of it. Both blocks are interconnected by electrical wiring and a copper pipeline, through which freon continuously circulates during operation.

Regardless of the design and dimensions, the indoor unit of a split system must have the following components in its design:

• Compressor. Responsible for the compression of the refrigerant and its circulation in a closed circuit.
• Evaporator (heat exchanger). Freon is converted from liquid to gas in this radiator.
• Fan. Forces the air flow going to the evaporator.
• thermostatic valve. Helps reduce refrigerant pressure before the evaporator. As a rule, it is a thin, spiral-curved copper tube.
• A set of filters. Detain dust and larger fractions of debris, inevitably contained in the room air.
• Air distribution system.
• Blinds responsible for the direction of air flow.
• Temperature sensors.
• LED indicators.
• Information table.

Indoor unit design

Note! Since the indoor unit of a split system is often located at an unattainable height, the device always includes a remote control.

The external unit is simpler, and instead of the evaporator, the device has a capacitor - a unit responsible for the phase transition of freon from a gaseous state to a liquid one.

MEL group of companies - wholesale supplier of air conditioning systemsMitsubishiHeavyIndustries.

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Before considering such a seemingly simple theme, as the maximum length of air conditioner pipelines (open the manufacturer's catalog and see what the maximum length is), I want to ask one question: what is an ENGINEER in our specialty? The one that looks into the directory and gives out what is written there? But this can be done by an ordinary manager, knowledge of hydraulics and thermodynamics is not necessary for this. Probably, an engineer is a specialist who sees a little deeper than the numbers in the catalog. A specialist who can explain where these numbers come from.

I remember there was a dispute with a respected person who, in defense of the catalogs, said the following phrase: “If I have instructions on how to build a BLUE house, then I cannot build a RED house using it, because this would be a violation of the instructions ... "

So here is an ENGINEER, this is probably a person who can build a "house" of any color: understanding what a foundation is, bearing walls, floors and roofing of the building. It does not matter what color the house will have.

Split air conditioning systems have one important characteristic– the maximum distance from the outdoor unit to the indoor unit. Moreover, on real objects, this parameter often becomes decisive when choosing an air conditioner. The greater the cooling capacity of the air conditioner, the greater the length of the air conditioner route is allowed by the manufacturer (Table 1 for example Mitsubishi Heavy industries).

Table 1.

For models of 2 kW of cold, the maximum length of the route for the air conditioner is, as a rule, 15 meters, and for semi-industrial models of 7 kW and above - up to 50 meters. For some models, the length of the pipelines can reach 100 meters.

But one important detail is often forgotten - the performance of the air conditioner in the catalogs is indicated with a standard length of pipelines of 7.5 meters, and with a maximum length, the performance of the air conditioner will be less. How much less - look at these tables:

Table 2.

Equivalent length - the length of a straight pipeline, the pressure loss in which is the same as the real one (with local resistances).

In principle, the power losses are not large - for the 50th model with a length of 30 meters (equivalent length), the losses during cold operation are only 3.4% of the power. On the other hand, for the 140th model, the losses for 50 meters of length are already 17%.

Now we need to turn our attention to theory.

On fig. 1 shows a classic freon cycle in an air conditioner circuit. And please note that this is a cycle for ANY systems based on R410A freon, the cycle does not depend on the performance of the air conditioner or brand. Let's start from point D, with the parameters at which (temperature 75C, pressure 27.2 bar) freon enters the condenser of the outdoor unit. Freon in this moment- this is a superheated gas, which first cools to the saturation temperature (about 45 ° C), then begins to condense and at point A, completely passes from gas to liquid. Then the liquid is supercooled to point A' (temperature 40C). It is believed that the optimal value of supercooling is 5C. After the heat exchanger of the outdoor unit, the refrigerant enters the throttling device (TRV or capillary) and its parameters change to point B (temperature 5C, pressure 9.3 bar). Moreover, it is important that after throttling, it is precisely the mixture of liquid and gas that enters the liquid pipeline. The greater the amount of supercooling of freon in the condenser, the more share liquid freon enters the indoor unit, the higher the efficiency of the air conditioner.

B-C - the process of freon boiling in the indoor unit with a constant temperature of about 5C, C-C '- freon overheating up to + 10C.

C ' - L - the process of freon suction into the compressor and pressure loss at the same time. A similar process is D' - M.

L - M - the process of compressing gaseous freon in a compressor with an increase in pressure and temperature.

Rice. 1. Freon cycle refrigeration machine on the I-lgP diagram

Freon R410A parameters at the key points of the refrigeration cycle

The pressure loss in the system depends on the freon velocity V and the hydraulic characteristics of the network:

Liquid pipeline - 0.3-1.2 m / s

Gas pipeline - 6-12 m/s

What will happen to the air conditioner with an increase in the hydraulic characteristics of the network (due to increased length or a large number local resistance)? Increased pressure losses in the gas pipeline will lead to a pressure drop at the compressor inlet. The compressor will capture refrigerant of lower pressure and therefore lower density. The refrigerant consumption will drop. At the outlet, the compressor will produce less pressure and the condensing temperature will drop. A lower condensing temperature will result in low temperature evaporation and freezing of the gas pipeline.

If increased pressure losses occur in the liquid pipeline, then the process is even more interesting: Since we found out that freon is in a saturated state in the liquid pipeline, or rather, even a mixture of liquid and gas bubbles, then any pressure loss will lead to a slight boiling of the refrigerant and an increase in the share of gas. An increase in the proportion of gas will lead to a sharp increase in the volume of the gas-vapor mixture and an increase in the speed of movement through the liquid pipeline. Increased speed movement will again cause increased pressure losses and the process will be "avalanche". Here is a conditional graph of specific pressure losses depending on the speed of freon in the pipeline:

Rice. 2. Freon pressure loss along the length of pipelines.

It can also be viewed as a graph of pressure loss along the length. If, for example, the pressure loss with a pipeline length of 15 meters is 400 Pa, then if the pipeline length is doubled to 30 meters, the losses increase not twice to 800 Pa, but 7 times to 2800 Pa. Therefore, a simple increase in the length of pipelines by a factor of two relative to its standard lengths fatal for the air conditioner.

How to increase the length of the traces more than the standard allowable values?

To do this, two problems need to be solved:

Problem 1 - the problem of increased pressure losses along the length in pipelines.

As we found out, increased pressure losses lead to a sharp decrease in the cold power of the air conditioner, a decrease in freon consumption and overheating of the compressor. Which in turn will lead to jamming or burning of the motor windings. To avoid this, we must reduce specific losses pressure by reducing the speed of movement in pipelines. Those. simply increase the diameters of the pipelines. Reducing the speed of freon by half reduces the pressure loss by 4 times (formula 1) and, accordingly, by the same amount allows you to increase the length of the pipelines.

To test this on real equipment, let's look again at Table 2: cold power losses for the 71st and 140th models at a length of 50 meters.

71st model correction factor 0.94. Losses 6%

140th model correction factor 0.829. Losses 17.1%

This means that the pressure loss decreased 17.1/6=2.85 times

The 140th model is exactly twice as powerful as the 71st, and the pipelines there are the same (3/8 and 5/8). Therefore, the speed of freon movement is exactly two times less. The pressure loss, which is quadratic with speed, should be around 36%. In fact, less, because the reference point is not from 0 meters, but from 7.5 meters.

That is, when the freon speed is halved, the pressure loss also decreases at least twice (in practice, more than twice).

Now let's look again at table 1:

The 6.35mm liquid line diameter works on both the 2.0kW system and the 7.1kW system. On the 7 kW model, the length of the pipes can reach 30 meters, which means that there are no critical pressure losses with such a length. The available pressure of the compressor, as we have already found out, does not depend on the power of the air conditioner. Therefore, the same liquid pipelines for models from 2 to 7 kW are explained by the absence of pipes of a smaller diameter. For models from 2 to 5 kW, the liquid pipeline is taken “with a margin”.

But the diameter of the gas pipeline is chosen closer to real values, so its cross section varies from 9.52 mm to 15.88 mm.

Given all of the above, we can make the following table:

Table 3. Magnification allowable length pipelines when changing their diameter.

Power loss at the specified maximum length will be from 10% to 15%. As shown in Table 2, MHI power losses are allowed up to 20%.

Problem 2 - oil return to the compressor.

By increasing the diameter of the gas pipeline, we reduce the speed of the refrigerant, which means that the effect of oil separation and stagnation in pipelines and “oil traps” may occur. To prevent this from happening, some MHI outdoor units have special devices - oil separators.

Rice. 3. Scheme of the freon circuit of the outdoor units FDC200 (250)VS

Table 5. Power loss of outdoor units 200 and 250 index at different diameters gas pipeline.

But most outdoors do not have oil separators. On the other hand, the problem of oil separation was more typical for R22 freon. First, because the viscosity mineral oil, used with R22 freon, more than polyester for R410A freon. Secondly, the density of R410A is higher, the available pressure is higher, so the pipeline diameters are 1-2 sizes smaller.

In any case, an increase in the diameter of gas pipelines is allowed ON HORIZONTAL AREAS. Those. on vertical sections of the pipeline, it is necessary to use a standard (catalogue) diameter, and on horizontal sections, you can switch to a diameter of a larger section.

Example:

In the residential complex of Perm, on each floor of the building there are special rooms for outdoor units of air conditioners. But the length of the pipelines that arises in this case reaches 40 meters. The maximum length of the route for a household split system of any manufacturer is a maximum of 25 meters. However, if the diameter of the gas pipeline is increased to 1/2, the length of the air conditioner pipeline can reach 40 meters. Household model SRK35ZJ-S installed. The area near the outdoor unit is performed as standard (1/4, 3/8), then a transition is made approximately at a distance of 1 meter gas pipe to the diameter of ½ on the solder, and then near the indoor unit, the reverse transition to 3/8. Liquid pipe unchanged.

More than 10 air conditioners have already been installed according to this scheme. The first one was over 2 years ago. All air conditioners are working fine.

Conclusions.

1. Increase maximum length routes of air conditioners are possible with an increase in the diameter of pipelines. Recommendations for the Mitsubishi Heavy Industries brand are shown in Table 3.
2. An increase in the diameter of the gas pipeline is possible only in horizontal sections.

At the same time, it is necessary to carry out additional charging of refrigerant for an increased length of the liquid pipeline according to table 4.