A sudden stop in the operation of a refrigeration unit often takes you by surprise, especially when there are perishable products inside. If the compressor is humming, but there is no cold, or it turns off quickly, and the condenser is barely warm, there is a high probability that something has happened. This thin part is a throttling device, and even a microscopic particle of oxide or moisture can disrupt the circulation of refrigerant throughout the system. clogged capillary tube. This thin part is a throttling device, and even a microscopic particle of oxide or moisture can disrupt the circulation of refrigerant throughout the system.
Diagnosis of such a malfunction requires care and compliance with safety precautions, since the work is carried out with a sealed circuit under pressure. Unlike simple mechanical breakdowns, this often requires not only physical removal of the plug, but also a complete refilling of the system with freon. Service center masters they call this one of the most common reasons for the failure of old and new alike models.
Before taking active steps, you need to clearly understand the structure of the circuit. The capillary connects the condenser and the evaporator, creating the necessary resistance for proper boiling of the refrigerant. If you notice that the filter drier is covered with frost or, conversely, heats up unevenly, this is a sure sign of a problem. Next, we will look at how to act in such a situation and whether it is possible to save the unit without calling an expensive team.
Signs and diagnosis of system blockage
The first symptom that is worth paying attention to is the nature of the operation of the motor-compressor. It can work continuously, trying to gain temperature, or it can turn on for a few seconds and immediately stall due to overload. Visual inspection also gives many clues: if condenser grid on the back wall remains cold or heats up only at the beginning of the cycle, gas circulation is impaired.
Particular attention should be paid to the filter-drier. Under normal conditions, it is at ambient temperature or slightly warm. When clogged, this element is often covered with a dense layer of frost or, conversely, becomes hot due to increased pressure in front of the plug. Sometimes a characteristic hissing or gurgling sound is heard, which stops after disconnecting the device from the network.
⚠️ Attention: If you hear a whistle or sudden changes in pressure when the refrigerator is operating, immediately disconnect the device from the power supply. Further operation may lead to depressurization of the circuit or failure of the compressor.
For accurate diagnostics, professionals use a pressure gauge manifold. When connected to the service pipe in vacuum mode, the arrow may show the deepest vacuum, but when the compressor starts, the pressure will not drop as expected, or will begin to rise too slowly. This indicates that capillary tube does not allow gas to pass through in the required volume.
Necessary tools and workplace preparation
High-quality repairs are impossible without specialized equipment. You will need not only a basic set of plumbing tools, but also instruments for working with refrigeration circuits. The main tool will be vacuum pumpwhich is necessary to remove moisture and air from the system before refueling. Without deep evacuation, any repair attempt is doomed to failure due to the formation of ice plugs.
Also indispensably the presence of a torch (gas or oxy-acetylene) for soldering copper tubes. It is important to use the correct solder and flux to ensure tight connections. To purge the system, a cylinder of dry nitrogen is often used, the pressure in which is regulated by a reducer. Nitrogen allows you to blow out contaminants and oxides that could have formed inside copper lines.
List of necessary equipment for the successful completion of the operation:
- 🔧 A set of pipe cutters and rollers for working with copper of different diameters.
- 🔥 Gas burner with fuel reserve and silver solder for soldering.
- 💨 Cylinder with dry nitrogen and a reducer for purging and crimping.
- ❄️ Vacuum pump and pressure gauge station for pressure control.
Don't forget to prepare new consumables: filter-drier, piece of copper tubes for replacing the capillary (if necessary) and, of course, the refrigerant itself. The brand of freon can be found on the compressor nameplate or in the technical documentation of the model Indesit, Atlant or any other brand. Using the wrong gas will lead to incorrect operation of the entire system.
☑️ Preparation for repair
Methods for removing blockages: from simple to complex
There are several ways to deal with blockages, and the choice depends on the type of blockage. If an ice plug has formed in the system due to moisture, prolonged drying with a vacuum pump sometimes helps. However, if the cause is solid debris or oxides, more aggressive intervention will be required. The method often used is hydraulic hammer or blowing with nitrogen under high pressure.
One of the effective methods is annealing the site of the suspected blockage. Copper expands when heated, which can destroy the structure of the cork. However, this method is risky and requires experience as it is easy to burn through the pipe. A safer option is to dismantle the capillary tube and replace it with a new one. The standard length and diameter are selected strictly according to the power of the compressor.
⚠️ Attention: Blowing by mouth is strictly prohibited! The exhaled air contains moisture, which will instantly freeze in the system and create a new, even more complex blockage. Use only technically dry gases.
If the blockage is localized in the filter drier, replacing it often solves the problem completely. This item is designed to trap moisture and debris. In some cases, craftsmen practice flushing the system with a special solvent, but this requires complete disassembly of the circuit and subsequent thorough drying. For the home craftsman, the most realistic option is to replace the capillary and filter with subsequent evacuation.
Why can’t you just blow it out with a compressor?
Using a conventional air compressor for a garage will not provide the necessary pressure and, most importantly, will not ensure dry air. The moisture contained in the compressed air will settle in the narrowest places of the system, turning into ice when the refrigerator is first started.
Technology for replacing the capillary tube and filter
The replacement process begins with carefully unsoldering the old tube from the condenser and evaporator. It is important not to damage adjacent elements and not to overheat the soldering areas. After dismantling, the old capillary is cleaned or disposed of, and a new section is installed in its place. The length of the new tube must be identical to the original, since the system directly depends on this parameter. performance systems.
The filter-drier must be changed along with the capillary. The old element cannot be restored or purged; its internal structure is already saturated with moisture and contaminants. When soldering a new filter, it is important not to overheat the housing by keeping the flame at a distance and using a damp rag to cool it. Soldering time should be minimal so as not to disturb the properties of the adsorbent inside.
Parameter correspondence table for different types of refrigerants:
| Refrigerant type | Tube diameter (mm) | Length (m) | Features |
|---|---|---|---|
| R134a | 0.66 - 0.71 | 2.0 - 4.5 | Sensitive to moisture, requires careful vacuuming |
| R600a | 0.66 - 0.80 | 1.5 - 3.0 | Explosive, requires work in a ventilated area |
| R12 (obsolete) | 0.66 - 0.71 | 2.5 - 5.0 | Prohibited for use, replaced by analogues |
| R404a | 0.80 - 1.00 | 1.0 - 2.5 | Used in low-temperature chambers |
After installing all elements, nitrogen pressure testing is performed to check the tightness. The pressure rises to 10-15 atmospheres, and the pressure gauge is left for several hours. If the arrow does not move, it means the soldering was done efficiently. Only after this can you proceed to evacuation and charging.
Evacuation and charging with refrigerant
Vacuuming is a critical step that should not be skipped. The remaining air and moisture vapor in the system will lead to an increase in condensation pressure and the formation of ice plugs. The process should last at least 30-40 minutes until the pressure gauge shows a deep vacuum (about -1 bar). Ideally, a two-stage high-performance vacuum pump is used. Charging is carried out by mass or pressure, depending on the type of refrigerant. For vacuum pump high performance.
Charging is carried out by mass or pressure, depending on the type of refrigerant. For R600a (isobutane), refilling is possible only by scale, since it is a flammable gas, and an error in dosage is dangerous. Freon R134a can be refilled by controlling the suction pressure and compressor current consumption. It is important to fill the system with the liquid phase, if the design allows it, or the steam phase, being careful.
Key points of correct filling:
- ⚖️ Using electronic scales for accurate dosing of the refrigerant.
- 🌡️ Temperature control in the refrigeration and freezers during operation.
- 🔌 Monitoring the current of the compressor windings using current clamps.
After refueling, the service pipe is sealed. Check the soldering area with soapy water for leaks. If there are no bubbles, you can plug in the refrigerator and observe its operation for several hours. Uniform cooling of the evaporator and the absence of frost on the filter drier indicate success.
Common mistakes and prevention of re-clogging
One of the most common mistakes is incomplete removal of old oil from the system. When the compressor windings burn or operate for a long time, the oil oxidizes and turns into acid, which then precipitates, clogging the capillary. Therefore, serious repairs often require flushing the circuit or replacing the compressor along with the capillary.
Also, craftsmen often neglect installing a new filter-drier, relying on "maybe". This is a serious mistake, since the filter resource is limited. The trapped moisture will instantly create a new plug. In addition, it is important to ensure cleanliness when soldering: the use of flux should be minimal, and its residues must be removed so that they do not circulate through the system.
⚠️ Attention: Technical characteristics of refrigerators, such as type of oil and brand of refrigerant, may vary even within the same model depending on the year of manufacture. Always check the nameplate on the compressor housing before starting work.
Preventing blockages involves timely repairs. If you notice that the refrigerator has begun to work worse, do not expect a complete failure. Early diagnosis allows for minimal costs. Regular defrosting (for No Frost models this is less important, but for drip systems it is important) also prolongs the life of the unit.
FAQ: Frequently asked questions
Is it possible to clean the capillary without nitrogen and a vacuum pump?
It is almost impossible to clean the capillary without professional equipment. Using compressed air cans to clean electronics will not provide the required pressure and volume and will also introduce moisture. Without a vacuum pump, you will not be able to remove this moisture, which will lead to an ice jam after a few hours of operation.
How much does it cost to replace a capillary tube in the service?
The cost consists of the price of materials (copper, filter, freon) and the complexity of the work. On average, repairs including capillary replacement and refilling can cost from 30% to 50% of the price of a new refrigerator, so it is often more advisable to consider purchasing new equipment, especially if the unit is old.
Why does the refrigerator freeze too much after replacing the capillary?
This may indicate an incorrect selection of the length or diameter of the new tube. If the resistance is too low, excess liquid refrigerant enters the evaporator. It is also possible that there is air left in the system or the wrong type of refrigerant is selected. It is necessary to reconfigure or replace the element with a suitable one.
How to understand that it is the capillary that is clogged and not the filter?
Often these elements fail together. However, if the filter is covered with frost, and the pipe before it is warm, and after it is cold, the problem may be there. If the entire circuit after the filter does not work, and the pressure at the outlet of the compressor is high, then the blockage is most likely located deeper in capillary tube. An accurate diagnosis is made after opening the system.