How to remove a clogged capillary tube in the refrigerator yourself

A sudden stop in the operation of the refrigeration chamber while the motor is functioning is a situation that causes panic in any home cook. Products begin to deteriorate, and calling a technician often means a wait of several days and significant costs. However, in many cases, the cause of the failure is a trivial clogging of the capillary tubewhich an experienced home craftsman can eliminate with the necessary tools and a nitrogen cylinder at hand.

The capillary tube is a throttling device that separates the high and low pressure zones in the circuit. It is through this thin channel that the liquid refrigerant enters the evaporator, where it boils and cools the chambers. The diameter of the channel is only about 0.6–0.8 millimeters, which makes it extremely vulnerable to any mechanical impurities, moisture or oxidation products that have gotten inside the system.

If you notice that the refrigerator is humming, but there is no cold, or the freezer is working, but mainly removing heat, do not rush to blame the compressor. In most cases, the problem lies in a violation of the circulation of freon. A diagnostic sign of a capillary blockage is the absence of characteristic gurgling and hissing when the motor is running, as well as complete or partial defrosting of the evaporator. Understanding the physics of the process will allow you to make the right decision about repairs.

Diagnostics and signs of system blockage

Primary diagnosis requires careful monitoring of the behavior of the unit. When this happens hydraulic clog, the compressor continues to operate normally, trying to pump the refrigerant, but encounters resistance. This often leads to overheating of the motor housing and tripping of the protective relay. You may notice that the refrigerator operates in cycles: it turns on, hums for 10-15 minutes, then clicks and turns off, after which the process repeats.

Feeling the condenser grille (radiator) on the back wall also gives important clues. In normal mode, it should warm up evenly over the entire area. If you observe that only the first third of the grate is hot, and the rest remains cold, this is a sure sign that the freon is not circulating throughout the entire circuit. The high-pressure zone is limited to the area up to the point of blockage.

There is also the concept of an “ice plug,” which is formed due to excess moisture in the system. Unlike mechanical debris, such a plug can periodically thaw when the refrigerator is idle and freeze again during operation. This creates the illusion that the device is either working or faulty. To eliminate such a problem, not only purging is required, but also vacuuming systems for removing moisture.

⚠️ Attention: If the compressor operates continuously without shutdowns, and the temperatures in the chambers do not decrease, this may indicate a freon leak rather than a blockage. In this case, independent purging without detecting and soldering the leak will not produce results.

Necessary tools and preparation of the workplace

Repair of the refrigeration circuit is a high-risk job and requires specific equipment. Simply “blowing” into the tube with your mouth or a car pump is not enough, since effective cleaning requires a pressure exceeding the operating pressure in the system, as well as absolute dryness and purity of the supplied gas. The master's main tool is a cylinder with technical nitrogen and reducer.

In addition to the pressure source, you will need a burner apparatus. This can be an oxygen-propane combination or more modern gas torches with MAPP gas cylinders, which provide flame temperatures of up to 2000 ° C, necessary for brazing. Copper tubes in modern refrigerators are soldered with hard solders containing silver, as they can withstand high pressures.

For work you will also need:

• 🛠️ Pipe cutter and rolling tool for preparing connections.
• 🔥 Soldering kit (torch, solder, flux).
• 🌡️ Vacuum pump and pressure gauge station.
• 🧪 New filter-drier (mandatory replacement when opening the circuit).

Preparation of the workplace involves ensuring good ventilation. Soldering releases harmful substances, and if a large amount of refrigerant leaks in a confined space, the oxygen concentration may decrease. It is also necessary to ensure free access to the back of the refrigerator and the unit compartment.

Technology for removing blockages using nitrogen purging

The process of removing blockages begins with access to the capillary tube. Usually it is soldered into a filter drier, which, in turn, is connected to a condenser and compressor. The first step is to release the residual refrigerant pressure (if any) and carefully disconnect the filter-drier from the condenser and capillary tube.

After dismantling the filter, it is necessary to determine the direction of purge. Most often, the blockage is localized at the entrance to the capillary or in the filter itself. Blowing is carried out strictly in the direction opposite to the movement of freon, or alternately from different sides, if the design allows. Nitrogen pressure is supplied through the reducer, gradually increasing to 10–15 atmospheres.

If the blockage is caused by waxing (hardening of oil at low temperatures), then simply blowing with cold gas may not help. In such cases, the area of ​​the capillary tube coming out of the freezer is carefully heated with a hair dryer or warm water, while applying pressure. This softens the plug and allows it to be pushed out with a gas stream.

⚠️ Attention: It is strictly forbidden to use open fire to warm up tubes under pressure or with freon residues. This can lead to an explosive reaction and fire due to the formation of phosgene when freon comes into contact with an open flame.

Replacing the filter-drier and vacuuming

Any opening of the refrigerator circuit requires mandatory replacement filter-drier. This element contains zeolite, a substance that absorbs moisture. Upon contact with atmospheric air, zeolite is instantly saturated with moisture and loses its properties. Installing an old filter or a new one, but left unpacked for more than 15 minutes, will negate all repair efforts.

The replacement process is as follows: after successfully purging the capillary tube and condenser, a new filter is soldered to the system. It is important to work quickly to minimize exposure of the internal cavities to air. Soldering must be done efficiently, without overheating the filter housing, since high temperature can damage the internal structure of the zeolite.

After installing all elements, the system is performed. This is a critical step that allows you to remove not only air, but also moisture vapor that may have gotten inside during repairs. The vacuum pump should run for at least 30-40 minutes. Stopping ahead of time will leave microscopic drops of water in the system, which during operation will turn into an ice plug. vacuum systems. This is a critical step that allows you to remove not only air, but also moisture vapor that may have gotten inside during repairs. The vacuum pump should run for at least 30-40 minutes. Stopping ahead of time will leave microscopic drops of water in the system, which will turn into an ice plug during operation.

Recharging with refrigerant and checking for leaks

The final stage is filling the refrigerator with freon. The amount of refrigerant is strictly regulated by the manufacturer and is indicated on the nameplate located on the housing. Overfilling or underfilling will lead to incorrect operation: in the first case, the condensation pressure and load on the compressor will increase, in the second, the required temperature will not be achieved.

Refilling is best done in the liquid phase through a filter drier (if there is an appropriate valve) or in the gas phase through the service pipe, weighing the freon cylinder on an accurate scale. After refueling, it is necessary to check the tightness of all soldered joints using a soap solution. The appearance of bubbles will indicate a soldering defect that needs to be eliminated.

Why can’t you refill “by eye”?

The amount of freon is calculated by engineers with an accuracy of up to a gram. Excess freon can lead to water hammer in the compressor, since the liquid refrigerant does not have time to completely evaporate in the evaporator and enters the cylinder, which is fatal for the piston group.

After successful startup and entry into operating mode (usually this takes several hours), the temperature in the chambers should be checked. A working refrigerator should gain temperature according to the passport, and the compressor operating cycle should be approximately 30-40% of the total time (for example, it works for 10 minutes, it stops for 20).

Typical mistakes during self-repair

Independent repair of refrigeration systems is full of nuances, ignoring which leads to repeated breakdowns. One of the most common mistakes is neglecting to replace the filter drier. Amateur DIYers often simply blow out the system, solder it, and hope for the best. The result is predictable: after a week or a month, a new ice plug forms, and the repair has to be started all over again.

The second common mistake is the use of inappropriate materials for soldering. Tin-lead soft solders used in plumbing are not suitable for high-temperature areas of the refrigeration circuit and may leak under vibration or heat. It is necessary to use hard copper-phosphorus or silver solders.

• ❌ No vacuuming of the system after soldering.
• ❌ Use of oxygen instead of nitrogen for purging (risk of oil fire).
• ❌ Attempting to clear the blockage with chemical solvents that can damage insulation of the compressor windings.

It is also worth mentioning the erroneous opinion that frequently turning the refrigerator on and off from the outlet helps to “defrost” the plug. This is not only ineffective, but also harmful to the starting relay and motor windings, which are not designed for frequent starts under load.

Is it possible to clean a capillary tube without nitrogen?

Theoretically, you can use compressed air, but this is highly not recommended. The air contains moisture which will cause corrosion and ice blockage. Nitrogen is an inert and dry gas. The use of other gases may lead to a chemical reaction with the compressor oil.

How much does it cost to replace a capillary tube during service?

The cost of work varies depending on the refrigerator model and region, but usually includes the cost of soldering, vacuuming, refilling and materials. This can be a significant part of the cost of a new budget refrigerator.

Why does the refrigerator freeze less quickly after repair?

The reason may be underweight of freon, the presence of an air lock in the system (poor vacuum) or partial residual blockage. It is also possible that during soldering the compressor was overheated or the internal structure of the capillary was damaged.

How often do you need to change the filter-drier?

The filter-drier is a consumable item, but in a closed, working system it lasts the entire service life of the refrigerator (10-15 years). Its replacement is required only when the circuit is opened for repair or when moisture is detected in the system.