The appearance of extraneous sounds during compressor operation or a complete lack of cold in the chambers often indicates serious problems in the refrigeration circuit. Owners of household appliances immediately start Googling how to clean the capillary tube in the refrigerator, hoping to quickly restore the functionality of the unit. However, it is important to understand that this element is part of a sealed system, and access to it requires specific knowledge and tools.
Capillary tube is a thin copper coil that serves as a choke for the refrigerant, reducing its pressure before entering the evaporator. If a blockage occurs in this unit, the circulation of freon stops and the refrigerator stops freezing. Diagnostics such a malfunction requires a careful analysis of the symptoms, since external signs may coincide with a gas leak or a compressor breakdown.
In this material we will analyze in detail why blockages occur, what methods exist to eliminate them and whether this procedure can be performed independently. Refrigeration circuit repair is a complex technical process where the cost of an error can lead to a complete replacement of expensive equipment.
Signs and causes of blockages capillary
The main symptom of blockage is uneven cooling or its complete absence when the compressor is running. The engine may hum continuously, trying to build up pressure, but no cold is produced. Often on capillary tube you can visually notice swelling or, conversely, flattening at the site of the blockage if you remove the back panel.
The causes of plugs are divided into several categories. Most often, moisture remains in the system, which freezes at low temperatures and blocks the passage. Copper oxidation products, flux residues after soldering, or mechanical particles that got inside during poor-quality installation also become a problem.
⚠️ Attention: An attempt to clean the tube without first pumping out the freon and evacuating the system will lead to the release of refrigerant into the atmosphere and guaranteed re-clogging.
Necessary tools and preparation
To carry out work to remove the blockage, you will need specialized equipment, which is rarely found in a home craftsman’s kit. You will definitely need a vacuum pump to remove moisture and air from the circuit, as well as a pressure gauge station to control pressure.
You cannot do without a torch (gas or oxygen) for soldering copper connections and a set of pipe cutters. For the cleaning itself, nitrogen under high pressure or special chemical solvents that dissolve oily deposits are often used.
- 🔧 Vacuum pump and pressure gauges to control the pressure in the system.
- 🔥 Gas torch with solder and flux to seal joints.
- 🧪 A nitrogen cylinder with a reducer for purging the circuit under pressure.
- 🧹 A syringe with a solvent (for example, isopropyl alcohol) for chemical flushing.
Before starting any manipulations, it is necessary to completely defrost the unit and provide access to the rear technical part. Safety when working with open fire and gas under pressure should be a priority.
Mechanical method of cleaning with nitrogen
The most effective and common way to remove solid plugs is nitrogen purging. This method allows you to push a foreign body out of a narrow channel due to a sharp pressure drop. To do this, the master unsolders capillary tube from the filter-drier and compressor.
Nitrogen is supplied to the system through a special reducer, which allows you to regulate the pressure. Usually a short pulse of several atmospheres is enough for the plug to come out. It is important to control the direction of flow so as not to damage other elements of the system.
Danger of using oxygen
Never use pure oxygen to purge the refrigeration circuit. When mixed with oil in the compressor, oxygen forms an explosive mixture that can detonate from a spark or high temperature during soldering.
If simple purging does not help, use the pressure test method, leaving nitrogen in the system for a while under the control of a pressure gauge. This also allows you to check the tightness of the connections after soldering.
Chemical flushing of the system
In cases where the blockage is caused by oil oxidation or freon polymerization, mechanical cleaning may be ineffective. Then chemical washing with special liquids is used. The solvent is poured into the circuit and left for a certain time to dissolve the deposits.
After exposure, the chemicals are removed along with the dissolved dirt using a vacuum pump. This process requires care, since residues of aggressive chemicals can destroy the compressor windings or damage rubber seals.
| Method | Efficiency | Complexity | Risks |
|---|---|---|---|
| Nitrogen purge | High | Medium | Tube rupture at high pressure |
| Chemical flushing | Medium | High | Damage to insulation and seals |
| Replacement of the section | Maximum | High | Error when soldering a new unit |
After using any liquids, long-term vacuum drying of the system is necessary. Residual moisture in the circuit is unacceptable, since it will freeze again and create a new plug.
Replacing the capillary tube
If cleaning capillary tube fails, or it is damaged by corrosion, the only way out is to replace it. This is a labor-intensive process that requires accurate calculation of the length and diameter of the new tube, since the performance of the refrigerator depends on these parameters.
The new tube is soldered into the system in compliance with all technologies. Particular attention is paid to the copper-copper and copper-aluminum junction (if the evaporator is aluminum), where special adapters or a steel insert are used.
☑️ Algorithm for replacing the tube
After installing the new one element, the filter-drier must be replaced. The old filter is already saturated with moisture and decay products, and its reuse will negate all repair efforts.
Evacuation and refrigerant charging
The final and critical stage is evacuation. Vacuum pump must work long enough to remove not only air, but and water vapor, which boil at low pressure even at room temperature.
Only after creating a deep vacuum is the refrigerant charged. The amount of freon must strictly correspond to the marking on the compressor or technical documentation. Overfilling or underfilling gas will lead to incorrect operation or breakdown of the compressor.
⚠️ Attention: Technical characteristics of refrigerators, such as the type of freon and its quantity, may vary depending on the model and year of manufacture. Always check the label on the body of your device before refueling.
The refueling process is controlled by scales and pressure in the system, as well as by the current consumption of the compressor. Accuracy at this stage it determines the durability of the repair.
Frequently asked questions and answers (FAQ)
Is it possible to clean the capillary without a nitrogen cylinder?
Theoretically, you can try to use a compressor from an old refrigerator to create pressure, but its power (usually 2-4 atm) is often not enough to break through a dense blockage. A nitrogen cylinder gives a short-term impulse of up to 10-15 atm, which is much more effective.
Why did the refrigerator stop freezing again after a month after cleaning?
Most likely, there was moisture left in the system that was not removed during vacuuming. During operation, it circulated and froze again in the narrowest place - the capillary. It is also possible that the filter drier has not been replaced.
Is it dangerous to solder the refrigerator tubes yourself?
Yes, it is dangerous. Working with open flames, pressurized gas and potentially flammable refrigerants requires skill. Improper soldering can cause gas leakage or oil fire in the compressor when exposed to oxygen.
What is the diameter of a standard capillary tube?
The internal diameter usually varies from 0.6 to 0.9 mm, and the length can range from 2 to 4 meters depending on the power of the compressor and the type of refrigerant. The exact parameters are individual for each model.