How to clean the capillary tube in the refrigerator yourself

The appearance of an ice “coat” on the back wall or the complete absence of cold in the chamber often indicates a violation of the refrigerant circulation. In most cases, the culprit is capillary tube, whose diameter is less than a millimeter, which makes it extremely vulnerable to microscopic contaminants. An attempt to clean this unit yourself requires not only accuracy, but also an understanding of the physical processes occurring inside the sealed circuit.

Clogging can be caused by frozen moisture or mechanical particles remaining after poor-quality installation. Before taking active steps, it is necessary to conduct a thorough diagnosis so as not to damage the expensive compressor or not to completely break the tightness of the system. In this article we will analyze proven methods for restoring the patency of the line.

Diagnostics of the blockage and its localization

The first sign that capillary has stopped passing freon in the required volume is the abnormal behavior of the condenser. If you notice that the grill on the back wall is hot only at the very beginning or, conversely, completely cold when the engine is running, this is an alarming signal. You can often hear gurgling or whistling coming from the evaporator area, which indicates an intermittent flow of gas.

To accurately determine the location of the plug, craftsmen use the palpation method. With the unit running, walk your hand along the tube leading from the filter drier to the evaporator. In the place where the tube changes temperature sharply or where the characteristic sound of gas passing under pressure is heard, it most likely formed. If the blockage is caused by ice, the tube will be unevenly covered with frost. plug. If the clog is caused by ice, the tube will be frosted unevenly.

It is important to distinguish a capillary blockage from a freon leak or a compressor malfunction. If the motor hums, but does not start or quickly turns off due to thermal protection, the problem may be deeper. Clogging often accompanied by an increase in discharge pressure, which creates additional load on the unit.

⚠️ Attention: If you find that the tube is swollen or has visible mechanical damage, a simple blowing will not help - a section of the line needs to be replaced and soldering.

Sometimes the reason why circulation stops is not a solid particle, but a paraffin plug formed when using low-quality oil or freon. Such a blockage is often temporary: after the refrigerator is completely defrosted within 24 hours, operation can be restored by itself.

Necessary tools and preparation

To perform work to restore the system's permeability, you will need a specific set of tools. Without them, intervention refrigeration circuit is impossible, since the creation of high pressure or vacuum is required. The main tool will be a compressor from an old refrigerator or a powerful car pump capable of delivering pressure up to 10-15 atmospheres.

It is also necessary to prepare consumables and auxiliary equipment. All tools must be dry and clean to avoid introducing new dirt or moisture into the system. Pay special attention to the condition of the hoses that will be connected to the system.

• 🔧 Set of pipe cutters and rolling machine for copper pipes.
• 🔥 Gas torch and solder for sealing connections.
• 🌬️ Nitrogen cylinder with reducer (preferably) or a prepared compressor.
• 🧤 Protective gloves and goggles for eye safety.

Before starting any manipulations, the refrigerator must be completely defrosted and dried. Connecting the unit to the network during work is strictly prohibited. If you plan to use an open fire for soldering, make sure that there are no refrigerant vapors in the room, since some types of freon emit toxic substances when in contact with fire.

Purge method with nitrogen or a compressor

The most effective way to eliminate mechanical blockages is considered to be purging the system under high pressure. To do this, you need to cut off the capillary tube from the inlet side (after the filter drier) and from the outlet side (before the evaporator). This will create a directed flow of gas that will push out the foreign body.

If you have access to a nitrogen tank, this is ideal. Nitrogen is inert and does not contain moisture, which is critical for refrigeration system. The pressure during purging must be controlled, usually within 10-15 atmospheres, so as not to rupture the thin walls of the tubes. At home, a conventional air compressor is often used, but in this case there is a risk of driving moisture inside the circuit.

The purge process is as follows: the pressure supply hose is hermetically connected to the cut end of the capillary. By briefly switching on the gas supply, a pulse is created that destroys the plug. If the blockage is serious, the procedure is repeated several times, sometimes changing the direction of flow (reverse blowing), although this is more difficult to implement technically.

⚠️ Attention: When using a conventional air compressor, be sure to install an additional moisture-oil separator, otherwise moisture will settle inside the system and freeze in a short time, forming a new, more complex plug.

The success of the operation is checked by the sound of escaping air and the feeling of the flow with the palm of your hand. If air passes freely and with a characteristic whistle, it means that patency has been restored. However, this does not yet guarantee full operation of the refrigerator, since there could be debris left in the system.

Rinsing the system with a solvent

In cases where air purging does not produce results, or there is a suspicion of the presence of paraffin deposits and oxides, chemical flushing is used. For these purposes, a special solvent is used, most often Freon R11 or specialized liquids for flushing refrigeration circuits, which leave no traces and quickly evaporate.

The solvent is poured into the system under pressure, dissolving contaminants. This method requires special care, as harsh chemicals can damage rubber seals or compressor windings if released in large quantities. After flushing, the system must be thoroughly dried with a vacuum pump.

Why can’t you use acetone or gasoline?

The use of household solvents such as acetone, gasoline or alcohol is strictly prohibited. They leave an oily film that disrupts heat transfer and can react with the compressor oil, forming an acid that will corrode the system from the inside.

Flushing technology involves cyclic supply of solvent. The liquid, passing through capillary, washes away dirt, which is then removed along with the flow. It is important to collect the used solvent in a separate container to assess the degree of contamination. If the liquid comes out cloudy with a suspension, the procedure is repeated until it becomes transparent.

After chemical treatment, long-term vacuumization is required. Remaining solvent must be completely removed, otherwise oil foaming and water hammer will occur when the compressor starts. This is one of the most risky stages, requiring a vacuum gauge to control the quality of drying.

Replacing the filter-drier: a mandatory step

Any intervention in a sealed circuit, especially related to cleaning the capillary, requires a mandatory replacement of the filter-drier. This small cylinder, installed in front of the capillary tube, contains zeolite or silica gel, which absorb moisture and trap mechanical particles. When the capillary is clogged, the filter, as a rule, is also clogged or saturated with moisture to the limit.

If you leave the old filter, it will quickly release the accumulated moisture back into the system when the temperature changes, and the clog will form again, but in the narrowest place - inside the new capillary or choke. Therefore, replacing the filter is not a recommendation, but a technical necessity. The replacement process is simple: the old filter is cut off, and a new one of the appropriate size is soldered in its place. It is important not to leave the new filter open in the air for more than 10-15 minutes, as it instantly begins to absorb atmospheric moisture, losing its properties. Soldering should be done quickly and efficiently, avoiding overheating of the filter housing. technical necessity.

The replacement process is simple: the old filter is cut off and a new one of the appropriate size is soldered in its place. It is important not to leave the new filter open in the air for more than 10-15 minutes, as it instantly begins to absorb atmospheric moisture, losing its properties. Soldering should be done quickly and efficiently, avoiding overheating of the filter housing.

When selecting a new filter, focus not only on the brand of the refrigerator, but also on the type of refrigerant used. Filters for R134a and R600a may have different adsorbents and throughput. Installing an unsuitable filter will lead to rapid failure of the entire system.

Evacuation and refrigerant charging

After successfully cleaning the capillary, washing and replacing the filter, it is necessary to remove air and remaining moisture from the system. A vacuum pump is used for this. The vacuuming process creates a vacuum at which water boils at room temperature and evaporates, leaving the circuit along with the air.

The duration of vacuuming depends on the power of the pump and the volume of the system, but usually ranges from 30 minutes to an hour. It is best to control the process using a vacuum gauge: the needle should go into the green zone and stay there steadily. If the arrow creeps back, it means there is a leak in the system.

Only after high-quality vacuumization is the refrigerator filled with freon. The amount of refrigerant must strictly correspond to the norm indicated on the unit nameplate (usually in grams). Underfilling will lead to poor cold, and overfilling will lead to increased energy consumption and possible water hammer in the compressor.

⚠️ Attention: Refilling must be done only in the liquid phase (by turning the cylinder over), if one type of freon is used, or strictly according to the instructions for mixtures. The use of scales is mandatory; refueling by eye is unacceptable.

After refueling, turn on the refrigerator and check its operation for several hours. The uniformity of cooling of the evaporator, the temperature of the condenser and the absence of extraneous noise are assessed. If all parameters are normal, the tubes are finally sealed.

Typical mistakes and safety measures

Independent repair of refrigerators is fraught with risks, and beginners often make critical mistakes. One of the most common is an attempt to clean the capillary without first removing all the freon from the system. This is not only dangerous for the environment, but can also lead to an explosion during soldering.

Another common mistake is using an open flame near plastic elements or insulation without proper protection. Copper has high thermal conductivity, and the flame can easily spread to adjacent parts. Always use a heat shield (metal plate) when soldering in hard-to-reach places.

• ❌ Never pinch copper tubes with pliers - this will deform the capillary.
• ❌ Do not ignore the burning smell - it may indicate overheating of the wiring or winding.
• ❌ Do not leave the system open longer than necessary to avoid moisture penetration.

It is also worth remembering electrical safety. Work is often carried out in humid conditions (after defrosting), so the use of working tools and grounded sockets is mandatory. If you feel unsure of your abilities at any stage, it is better to stop and call a professional.

Remember that modern refrigerators are becoming more and more complex, and in some models the capillary tube is soldered directly into the evaporator body or foamed into closet walls. In such cases, cleaning is impossible without destroying the structure, and it is necessary to replace the entire evaporator or re-hang the system onto an external circuit.

Is it possible to clean the capillary without unsoldering it from the system?

Theoretically, there are methods of chemical washing without opening the circuit, but their effectiveness is extremely low. Without creating a directed high pressure flow and replacing the filter drier, the result will be temporary or negative. A full repair requires depressurization.

How much does it cost to clean the capillary at the service?

The cost depends on the region and model of the refrigerator, but usually consists of the price for the work, the cost of a new filter, freon and consumables. On average, this is cheaper than replacing the compressor, but more expensive than attempting to repair it yourself.

Why did the refrigerator start to freeze worse after cleaning?

This may indicate incomplete removal of moisture (residual moisture froze in the capillary), incorrect dosage of freon, or damage to the capillary tube during cleaning (the cross-section has changed). It is also possible that the blockage has not been completely removed.

What is the danger of moisture getting into the system?

Moisture in the refrigerator system is the main enemy. At low temperatures it turns into ice crystals, which clog the capillary. In addition, water reacts with freon and oil, forming an acid that corrodes the metal from the inside, leading to through corrosion holes.