Faced with a situation where your Atlant refrigerator stopped freezing, but the compressor is working properly, many owners They immediately suspect a freon leak. However, one of the common reasons for the lack of cold is a banal blockage capillary tube. In this narrow line, the diameter of which is a fraction of a millimeter, even a microscopic particle of oxide or a frozen paraffin plug can completely stop the circulation of the refrigerant.
The problem can be solved, but requires accuracy and understanding of the physics of the processes. An attempt to remove the blockage “blindly” can lead to depressurization of the system or damage to the compressor. Cleaning the capillary tube is a procedure available to a technician with a certain set of tools, but requires strict adherence to technology.
In this article we will look at what methods exist to free the line from plugs, how you can bleed the system and why some methods are categorically not suitable for modern models Atlant. You will learn how to diagnose a blockage, and not another malfunction, and what tools are needed for successful repair.
⚠️ Attention: All work related to depressurization of the refrigeration circuit must be carried out in compliance with safety precautions. The refrigerant is under pressure, and an open flame when soldering requires caution.
Diagnostics of a clogged capillary system
Before looking for how to clean the system, you need to make sure that the problem lies there. capillary tube. The symptoms of a blockage are often disguised as other problems. The first sign is a working compressor that hums continuously or works in cycles, but there is no cold in the chambers at all, or it is very weak.
If you touch the condenser (the grille at the back or the side walls), it will be cold or barely warm, although the motor-compressor is hot. Frost may form at the point where the capillary tube enters the evaporator or on the filter drier, or, conversely, this area remains at room temperature, while the rest of the circuit behaves differently. Diagnostics blockage also includes listening to the operation of the unit: sometimes gurgling or whistling is heard, followed by silence.
For an accurate check, technicians often use the heating method. If you heat up the filter drier, but the pressure in the system does not change or the pressure gauge shows a vacuum where there should be pressure, this is a sure sign clogged capillary. It is also worth inspecting the oil leaking during depressurization: the presence of acid or strong dirt will confirm the need for serious flushing of the entire system.
Preparation of equipment and tools
For high-quality cleaning you will need a specialized tool. Simply “blowing” with your mouth or a household pump is not enough, since you need to create high pressure or vacuum. The main tool will be nitrogen cylinder with a reducer that allows you to regulate the pressure up to 10-15 atmospheres. Nitrogen is inert and does not oxidize the inner walls of the tubes, unlike oxygen or air.
A vacuum pump is also needed to help draw out any remaining moisture and debris after purging. To connect the nodes you will need a torch (gas or oxy-acetylene), solder and flux. Do not forget about a new filter drier, since the old one must be replaced after the circuit is opened and moisture enters.
The flushing liquid is most often used specialized solvents or purified freon R12/R134a in the liquid phase, but nitrogen purge is considered more reliable for removing solid particles. It is important to prepare a container for collecting old oil and a rag for wiping connections.
☑️ Cleaning tools
Purge method with nitrogen under pressure
The most effective The way to clean capillary tubeis considered to be blowing with dry nitrogen. This method allows you to mechanically dislodge the plug using a high-pressure gas stream. The process begins by disconnecting the refrigerator from the network and accessing the technical area, usually located at the back of the unit.
It is necessary to cut the filling tube and the process pipe of the compressor. Then a nitrogen cylinder is connected to the system through a reducer. The pressure should be increased gradually, starting from 5 atmospheres, and monitor the system’s reaction. If the blockage is not critical, a stream of nitrogen can push particles of oxides or paraffin through the filter into the condenser.
Blowing is best done in both directions if it is technically possible to disconnect the capillary from the condenser. Often a plug forms at the entrance to the capillary or in the filter itself. If, when 10-12 atmospheres are supplied, the gas does not pass, but only a whistle or hissing is heard, it means the blockage is solid and requires the use of other methods or replacement of the unit.
Why nitrogen?
Nitrogen does not react with oil and metal at high temperatures, as opposed to oxygen, which can cause an explosive mixture with oil vapor, or air containing moisture, which will lead to the formation of acid inside the system.
Use of a hydraulic press and flushing
In cases where gas purge does not help, the hydraulic pressing method is used. The essence of the method is to create high pressure of a liquid (oil or special solvent) in a closed circuit. For this, a manual hydraulic press is used, capable of developing a force of several tons.
The system is filled with flushing liquid, and pressure is created that softens paraffin deposits and washes out small fractions of dirt. This method is more gentle on the tubes than impact methods, but requires more time. After flushing, the system must be dried with a vacuum pump for a long time to remove residual solvent.
Sometimes craftsmen use the method of “pressure testing” with the refrigerant itself, but this requires a large amount of freon and special equipment to collect it. Flushing is effective when the system is contaminated with oil breakdown products, which form a viscous coating on the walls capillary tube.
⚠️ Attention: When using the hydraulic method, monitor the integrity of the solder joints. A sharp increase in pressure can rupture the thin walls of the condenser tubes, which will require not cleaning, but complex repairs with replacement of components.
Replacing the filter-drier and capillary tube
Often the question “how to clean it” transforms into the need for replacement. A capillary tube is a product with a very thin channel, and if the blockage is not caused by a one-time particle, but by systemic contamination or “collapse” of the tube, cleaning will not have a long-term effect. In such cases, replacing the capillary tube is the only correct solution.
The replacement process is labor-intensive: it is necessary to dismantle the old tube, unwinding it from the evaporator body (if it is foamed), or solder it off. The new tube must have a strictly defined length and diameter specified in the technical documentation for your model Atlant. Any deviation will change the boiling pressure and the operation of the entire refrigerator.
A new one is always installed simultaneously with replacing the tube. filter drier. This element is responsible for trapping moisture and microscopic debris. An old filter, once exposed to air, instantly absorbs moisture from the atmosphere and loses its properties, becoming a source of future problems.
Table: Comparison of methods for eliminating blockages
For the convenience of choosing a method for eliminating a malfunction, we will consider the main characteristics of each approach in the comparative table. This will help estimate labor costs and required resources.
| Method | Efficiency | Complexity | Required equipment |
|---|---|---|---|
| Nitrogen purging | High | Medium | Nitrogen cylinder, reducer |
| Hydraulic flushing | Medium/High | High | Hydraulic press, solvent |
| Replacement of capillary | Maximum | Very high | Turn, solder, new tube |
| Vacuum | Low (as a separate method) | Low | Vacuum pump |
As can be seen from the table, replacing the element is the most radical, but also the most reliable way. However, if the blockage is caused by an accidental particle that entered during assembly or due to the destruction of the filter, then purging with nitrogen often allows you to restore functionality without completely overhauling the system.
It is important to understand that after any intervention in a sealed circuit, high-quality evacuation is required. Residual moisture in the system during operation of the compressor will turn into an ice plug, which will block the capillary again, and the entire repair will have to be repeated again.
Prevention of repeated blockages
To ensure that the question “how to clean the capillary tube” no longer arises, it is important to follow the operating rules. The main enemy of the system is moisture and overheating. Do not allow the refrigerator to operate for long periods of time with the door open and keep the condenser at the back of the unit clean.
Regular defrosting (for No Frost models this is not required, but drainage control is important) and timely replacement of door seals will help avoid unnecessary load on the compressor. You should also avoid frequent power surges in the network, which can cause overheating of the oil and its decomposition.
Frequently asked questions (FAQ)
Is it possible clean the capillary tube with a syringe?
Theoretically, by creating high pressure with liquid in a medical syringe, you can try to break through a slight blockage. However, the force of a human finger rarely exceeds several atmospheres, while 10-15 atmospheres are needed for effective cleaning. This method can only work with very light contamination and is more often used to diagnose patency rather than for full repairs.
Why can’t you use oxygen for purging?
The use of oxygen is strictly prohibited. When mixed with compressor oil vapor and in the presence of a spark (for example, from static electricity or a nearby burner), a powerful explosion can occur. In addition, oxygen causes oxidation of the inner walls of the tubes, creating new contaminants.
How long does it take to vacuum the system after cleaning?
The minimum operating time of the vacuum pump should be 30-40 minutes for small systems. However, professionals recommend holding the vacuum for at least 1 hour to ensure that there are no micro-leaks and to ensure that all moisture that could have entered the system during repairs is removed.
Is it possible to restore an old filter drier?
No, the filter drier is a disposable element. Inside it is zeolite or silica gel, which, after being saturated with moisture, lose their properties. Heating or drying at home will not restore their effectiveness, but will only damage the structure of the sorbent. Always install a new part.