Everything about the outdoor unit of the air conditioner. External unit of the air conditioner: size, installation, maintenance Schematic diagram of the air conditioner

Air conditioners have long been a common household appliance. Of all the variety of devices for air cooling, the most popular are split systems, consisting of two unit-blocks, one of which is installed outside the room, and the other is inside. The indoor unit of an air conditioner is a complex device that takes warm air from the room and sends it back cooled down.

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

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

Regardless of the design and dimensions, the internal block of the split system necessarily has the following components in the design:

• Compressor. Responsible for the compression of the refrigerant and its circulation in a closed loop.
• Evaporator (heat exchanger). In this radiator, freon is converted from liquid to gas.
• Fan. Forces the air flow to the evaporator.
• Thermostatic expansion valve. Helps to reduce refrigerant pressure in front of the evaporator. As a rule, it is a thin copper tube curved with a spiral.
• A set of filters. Retains dust and larger fractions of debris inevitably contained in room air.
• Air distribution system.
• Louvers responsible for the direction of the air flow.
• Temperature sensors.
• LED indicators.
• Information table.

Indoor unit design

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

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

The introduction of new technological solutions into household equipment often runs counter to practical feasibility. The example of climatic technology is most indicative in this sense. So, recently, the market has been actively filled which are intended for indoor use. The features of such systems include the complete elimination of dirty installation operations, which attracts a large audience of consumers. But with all the convenience of installation and further maintenance, such models are not able to approach the performance characteristics that are provided by an external air conditioner unit as part of a split system. Another thing is that the owners of outdoor installations have to face troublesome tasks, but of a different kind.

What is an external unit?

The outdoor segment, which is part of the split-system complex, includes a condenser, valve decouples, pipes, filter driers and a fan. The internal "filling" may vary depending on the modification and constructional design, but a traditional set of an air conditioner with a remote block has just such a set of elements. By the way, the most noticeable differences are observed in the so-called winter systems, which provide for the presence of special controllers to control the fan. Modern air conditioners also use multifunctional power switching relays. Such devices are designed for non-standard compressor operation at high or low temperatures. Unlike the indoor segment, the outdoor unit does not have electronic modules - its operation is completely subordinated to the mechanical function.

Block dimensions

The outdoor unit is available on the market in various configurations and shapes. And although manufacturers in order to simplify segmentation are trying to unify model lines, the choice of standard sizes is still quite wide. If we talk about average parameters, it is 770 mm wide, 450 mm high and 245 mm thick. At the same time, the fan radius on average varies from 200 to 250 mm. Of course, there are also aggregates whose dimensions deviate from these indicators. So, in the Mitsubishi lineup, an external air conditioner unit is presented with an almost square shape, which is 880 mm in width and 840 mm in height. As for the parameters of the inner segment, they are not so impressive. Usually these are long narrow modules of medium size - 700 x 200 x 200 mm.

Choosing a place to install the unit

Usually, when choosing the optimal point for installing air conditioners outside, users are faced with the problems of combining ease of use and protection of the module. For example, placing the unit at a height is the best option from the point of view of its safety, but in this case it becomes more difficult to access the air conditioner for maintenance purposes. A good solution might be to place the module on the wall near a window opening or loggia. At the same time, other nuances must be taken into account, including the absence of direct rays of the sun and permission for installation from the neighbors, since a noisy unit can cause inconvenience to people living at the same level of the building.

In addition, it generates condensation, which will drip downward. Accordingly, you will have to negotiate with the neighbors on the lower floors. In case of successful coordination of the installation site of the unit with other residents, you can proceed to direct installation operations. By the way, another condition for the installation of the outdoor unit is the possibility of laying communications in the wall.

Installation of the outdoor unit of the air conditioner

When installing air conditioners, special mounting kits are used, which include pipes with flex, brackets with sets of fixing hardware, drainage communications, etc. The physical installation of the segment is carried out using load-bearing components that are embedded in the walls using anchor elements. At the same stage, brackets are used, the power potential of which is focused on the mass of a particular module. Also, the installation of the external unit of the air conditioner provides for its communication connection with the internal segment. To do this, a hole of the required diameter is made in the wall, which will allow organizing, in addition to the main wiring, also the laying of the vacuum pump and gauge manifold. At the final stage, the communications are directly connected between the two blocks.

Features of installing the indoor unit

When installing the evaporative, that is, the indoor module of the air conditioning system, it is especially important to maintain the correct position of the unit. Usually this unit is mounted directly under the ceiling surface with a slight indentation. Mechanical fixation is also done with suitable brackets. True, in this case, the mass of equipment is not so great, which simplifies the workflow. After marking, the master installs the anchoring elements and, if necessary, fixes the supporting profiles. Next, the indoor unit of the air conditioner is installed in strict compliance with the horizontal position. Also, some models of such segments, according to the instructions, should have a slight slope towards the drainage passage.

Maintenance and care

In normal operation, the air conditioner must be serviced every six months. Most of the work is carried out with the external unit, which is most susceptible to contamination. Specialists usually check the condition of the filters, the level of the refrigerant, the operating pressure of the module route, etc. The most difficult operation is the replacement of the working fluid. The refrigerant is a chemically unsafe substance, so it is better to rely on experienced craftsmen to recharge it. But care for the rest of the components is quite affordable for ordinary users. For example, the answer to the question of how to clean the external unit of the air conditioner is quite simple. First of all, it should be disassembled, after which, using a rag or a vacuum cleaner, rid the inner surfaces of the module from dust and dirt deposits. In the process of such maintenance, external filters and heat transfer radiators are cleaned, which prolongs the life of the air conditioner.

Outdoor unit in multi-systems

The concept of technical implementation of a split system provides for the possibility of using several indoor modules in one complex, which are served by one outdoor unit. Unlike standard configurations, the external module of such a system has engineering differences. For integration into a multi-system, it is equipped with an additional thermostat, which allows more efficient control of the fan and compressor settings. In turn, the indoor unit of the air conditioner acts as a source of information signals that determine the control of the outdoor unit. That is, the user uses the remote control to access the panel of the indoor unit, and that, in turn, through the digital channel, regulates the bypass communications system on the freon line.

Price question

In modern modifications, split-system air conditioners are not cheap, which is largely due to the complexity of the design. Even in the entry-level segment, the cost of an air conditioner with a remote unit is rarely less than 20 thousand rubles. Of course, you can find options for 15 thousand rubles. from little-known brands, but their quality raises doubts both among specialists and among users themselves, who often complain about problems.

Decent quality models are offered by Fujitsu, Daikin, Mitsubishi, etc. The average cost of an air conditioner from the range of these companies varies in the range of 30-40 thousand rubles. Moreover, the most technologically advanced and productive sets can be estimated at 70-80 thousand rubles.

Conclusion

The use of air conditioners with a design involving the installation of an external unit gives rise to many problems during installation and further maintenance. And this is without taking into account the difficulties in transporting equipment. These factors make it possible to speak of such units as morally obsolete. Especially against the background of the proliferation of mobile devices of modest size. Nevertheless, the outdoor unit of the air conditioner remains relevant in the market. This is explained by its high performance, functionality and safety during operation, since the main working units are located outside the living quarters. And if for domestic use you can find a low-power replacement for a split-system in the form of a monoblock, then in the context of servicing office premises, public buildings and institutions, multifunctional complexes are still unmatched.

Often, during renovations, many people think about installing a split system and plan to design rooms for the size of the air conditioner. The internal block of this device must be placed in such a way that it is not only correctly positioned, but also looks the most harmonious in the intended interior.

The purchase and selection of the air conditioner itself is often planned closer to the end of the repair, and you need to supply the "power" now. So this article was written for such cases. In it, we will consider in detail what distances must be taken into account for subsequent installation, and we will identify the most universal dimensions of indoor units (wall-mounted household devices).

First, we want to warn you right away that there are “non-standard” models of air conditioners that can have unique dimensions and characteristics. Therefore, this article should not be taken as 100% universal.

Air conditioner size. Internal block of a split system

Most often, living rooms have a small area (up to 25 sq. M.) For such rooms, air conditioners up to 2.7 kW are suitable (not to be confused with power consumption) - they are usually called "Sevens" or "nines"... As a rule, "sevens" and "nines" (of the same model) have the same overall dimensions, as well as the same tube diameter. Therefore, further we will take into account the same dimensions and characteristics of the considered standard sizes.

Overall dimensions of the indoor unit, which are of interest to us in the first place

• block length. The most standard length of indoor units is 700-800 mm. Slightly less common up to 900 mm. From personal experience, it is best to take into account an average length of 770 mm.
• block height. Most often, these dimensions are in the range of 250-290 mm. For planning we will take into account 270 mm.

The depth is not of much interest to us (170-240 mm). Thus, we have identified the average size of the indoor unit 770 x 270 mm.

Distances from walls and ceilings

1. On / off air conditioners. We bring out the cable in such a way that it is subsequently under the indoor unit ( to the left by 300 mm. and lower by 100 mm. from the center of the block).
2. Most

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Before considering such a seemingly simple topic as the maximum length of air conditioner pipelines (open the manufacturer's catalog and see what is the maximum length), 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 an ordinary manager can also do this, knowledge of hydraulics and thermodynamics is not needed for this. An engineer is probably a specialist who sees a little deeper than the catalog numbers. A specialist who can explain where these numbers come from.

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

So an ENGINEER is probably a person who can build a “house” of any color: understanding what the foundation, load-bearing walls, floors and roof of a building are. It doesn't 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 higher the cold performance of the air conditioner, the longer the length of the air conditioner route is allowed by the manufacturer (Table 1 for Mitsubishi Heavy Industries as an example).

Table 1.

For models of 2 kW of cold, the maximum length of the line for an 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, piping lengths can be up to 100 meters.

But they often forget about one important detail - the performance of the air conditioner in the catalogs is indicated with a standard pipe length of 7.5 meters, and with the maximum length, the air conditioner performance will be less. How much less - let's 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 loss for 50 meters of length is already 17%.

Now we need to pay attention to the theory.

In fig. 1 shows the classic freon cycle in the air conditioner circuit. Moreover, please note that this is a cycle for ANY systems 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 in which (temperature 75C, pressure 27.2 bar) freon enters the condenser of the outdoor unit. Freon at the moment is a superheated gas, which first cools down to saturation temperature (about 45C), 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 subcooling is 5C. After the heat exchanger of the outdoor unit, the refrigerant enters the throttling device (expansion valve or capillary) and its parameters change to point B (temperature 5C, pressure 9.3 bar). Moreover, it is important that after throttling, it is the mixture of liquid and gas that enters the liquid pipeline. The greater the amount of freon supercooling in the condenser, the more the proportion of liquid freon enters the indoor unit, the higher the efficiency of the air conditioner.

В-С - the process of freon boiling in the internal block with a constant temperature of about 5С, С-С '- freon overheating up to + 10С.

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

L - M - the process of compression of gaseous freon in a compressor with increasing pressure and temperature.

Figure: 1. Freon cycle in the refrigeration machine on the I-lgP diagram

Freon R410A parameters at the nodal points of the refrigeration cycle

The pressure loss in the system depends on the freon speed 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 if the hydraulic characteristic of the network increases (due to increased length or a large number of local resistances)? Increased pressure losses in the gas line will lead to a pressure drop at the compressor inlet. The compressor will pick up refrigerant with a lower pressure and therefore a lower density. The refrigerant flow will drop. At the outlet, the compressor will deliver less pressure and the condensing temperature will drop. A lower condensing temperature will result in a lower evaporating temperature and freezing of the gas line.

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, 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 vapor-gas mixture and an increase in the speed of movement along the liquid pipeline. Increased travel speed will again cause increased pressure loss and the process will be "avalanche". Here is a conditional graph of specific pressure losses depending on the speed of movement of freon in the pipeline:

Figure: 2. Loss of freon pressure along the length of the pipelines.

It can also be viewed as a graph of pressure loss along the length. If, for example, the pressure loss with a pipe length of 15 meters is 400 Pa, then when the length of the pipelines is doubled - up to 30 meters, the losses increase not twice to 800 Pa, but 7 times to 2800 Pa. Therefore, simply doubling the length of the piping in relation to its standard length is fatal for an air conditioner.

What is the correct way to increase the length of traces beyond the standard permissible values?

This requires solving two problems:

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 seizure or burning of the motor windings. To prevent this from happening, we must reduce the specific pressure loss by reducing the speed of movement in the pipelines. Those. just increase the diameters of the pipelines. Reducing the speed of the freon movement by half reduces the pressure loss by 4 times (formula 1) and, accordingly, by the same number of times allows to increase the length of the pipelines.

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

The 71st model has a correction factor of 0.94. Loss 6%

140th model correction factor 0.829. Loss 17.1%

This means that the pressure loss decreased 17.1 / 6 \u003d 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 movement of freon is exactly two times less. The pressure loss, which obeys a quadratic dependence of the speed, should be about 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 two times (in practice, more than two times).

Now let's take another look at Table 1:

Liquid line diameter of 6.35 mm works on both a 2.0 kW system and a 7.1 kW system. On a 7 kW model, the length of pipes can reach 30 meters, which means that there are no critical pressure losses with this length. The available compressor pressure, as we have already found out, does not depend on the capacity of the air conditioner. Therefore, the same liquid lines 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 was chosen closer to the real values, therefore its cross-section changes from 9.52 mm to 15.88 mm.

Considering all of the above, the following table can be drawn up:

Table 3. Increase in the permissible length of pipelines when changing their diameter.

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

Problem 2 - Oil return to compressor.

By increasing the diameter of the gas pipeline, we reduce the speed of movement of the refrigerant, which means that the effect of oil separation and stagnation in pipelines and "oil traps" can occur. To prevent this from happening, some MHI outdoor units are equipped with special devices - oil separators.

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

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

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

In any case, an increase in the diameter of gas pipelines is allowed ON HORIZONTAL AREAS. Those. in vertical sections of the pipeline, it is necessary to use the standard (catalog) diameter, and in 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, special rooms are allocated for outdoor units of air conditioners. But the length of the pipelines, which arises in this case, reaches 40 meters. The maximum length of the route of 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 mounted. The section near the outdoor unit is made in a standard way (1/4, 3/8), then at a distance of about 1 meter, the gas pipe transition is made to a diameter of ½ by soldering, and then near the indoor unit, the reverse transition is 3/8. Liquid pipe unchanged.

More than 10 air conditioners have been installed according to this scheme. The very first one more than 2 years ago. All air conditioners are working properly.

Conclusions.

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

At the same time, it is necessary to carry out an additional charge of refrigerant for an increased length of the liquid line in accordance with table 4.

During the operation of the household split system, you can feel an unpleasant smell of rot along with the air flow from the device. It indicates the need for preventive cleaning of the unit. In addition to the repulsive amber, clogging of units can cause rapid wear of the power unit, increased power consumption and the occurrence of allergic reactions in humans.

This procedure can be entrusted to an employee of the service center. But if you have been using the split system for a long time, then you can cope with the work yourself, saving money. You just need to familiarize yourself with the disassembly procedure and preventive cleaning.

Indoor unit dimensions

Before installing the indoor unit of the air conditioner, you should inquire about its dimensions. This is especially important during repairs, because modern technologies quite often provide for the installation of suspended ceiling systems that 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 dimensions. Block lengths usually range from 700 to 800 mm. Somewhat less common are products up to 900 mm. Experts recommend taking into account an average length of 770 mm.

As for the height, it is usually 250-290 mm. The average value is 270 mm. The depth is of little interest to consumers, but it reaches 240 mm. The minimum value is 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. There are many contradictions on this issue. In some instructions the minimum distance is 50 mm, while in others it is 300 mm. The optimal value is equal to a figure from 60 to 150 mm.

Specialists usually install an air conditioner 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 pitch between them and the split system is usually 150 mm. This value can be increased up to 250 mm. The average distance from the block to the wall is 400 mm.

Indoor unit classification

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

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

The most common are wall-mounted models, which are more affordable and are sometimes also called household. Their installation can be carried out in a room for any purpose, and a power within 7 kW allows you to cool up to 70 m 2 of the area. Such blocks are usually installed in the upper part of the wall, close to the window, since the design provides for the presence of an outdoor block, and the nodes must be interconnected.

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

In addition to household air conditioners, some manufacturers supply semi-industrial appliances to the market with a capacity of up to 10 kW. Outwardly, they resemble traditional split systems, but in terms of their parameters they are semi-industrial equipment.

Ducted air conditioners are installed with false ceilings that completely hide them. The distribution of cooled air is provided by means of heat-insulated air ducts, which are located in the space between the ceiling. Such structures can cool several rooms at once. The power of the equipment reaches 25 kW, which allows for cooling a cottage or several rooms of an apartment. The main feature of duct systems is the ability to supply fresh air in the volume that is guaranteed by the functioning of full ventilation.

Cassette A / C units require a false ceiling during installation. When compared to ducted designs, cassette units distribute cooled air through the bottom of the unit. It is covered with a decorative grille and usually has the following dimensions: 600 x 600 and 1200 x 600 mm.

Disassembling and cleaning the air conditioner

To clean the indoor unit of the air conditioner, it is necessary to disassemble it. For this, screwdrivers of various configurations and sizes are prepared. Care should be taken to provide a collection box for the fasteners. You will need an electrical and functional diagram of the device. In some models, they are printed on the inside of the top cover.

To clean the internal elements you will need:

• clean rags;
• detergent;
• vacuum cleaner.

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

When disassembling the indoor unit of the air conditioner, you will need to remove the 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. The brush will help with this.

The air flow guides must also be removed. The blinds are removed from the grooves. To facilitate the process, you need to bend them slightly. 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 detach the bottom cover. You will need to remove the drain tube and power cord. In the process, press out the three latches and disconnect the drain tray from the unit together with the outlet hose.

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 the transformer are removed. In order to take out the first one, it is necessary to squeeze out the 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, unscrew the bolts that are attached to the chassis. The evaporator is lifted and the motor is pulled outwards together 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 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 must be used for this, but the device must be powerful enough to extract dust from external filters and heat transfer radiators.

Independently or with the help of specialists

If the unit is located at an impressive height, then you can unscrew the protective grill and vacuum it, as well as wipe the inside of the dust. If not, you can seek the help of a professional who will remove the air conditioner using climbing equipment or a tower. Cleaning yourself can be done with the help of 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 "coat" of dirt is formed. This impedes the flow of air when blowing through 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 required even if you see black flakes flying out of the device. This suggests that the amount of dirt is so large that it does not hold on to the internal nodes. As a preventive measure, from time to time you can dismantle the fan and wash it with chemicals. But not all models make it easy to remove this part of the system.