The situation when the refrigerator stops freezing and the compressor runs without stopping often indicates a leak in the system or a blockage. In most cases, the cause lies in a thin copper line known as capillary tube. It is this element that is responsible for creating the pressure difference necessary for effective cooling of the chambers. If you are faced with the need to replace it, it is important to understand that the process requires not only theoretical knowledge, but also specific skills in working with metal and refrigerants.
Inserting a new tube is not just a mechanical action, but a complex operation to restore the refrigeration circuit. Errors at this stage can lead to repeated equipment failure or complete destruction of the compressor. Therefore, before starting work, you need to carefully study the structure of your unit and prepare the appropriate tool. We will analyze all the nuances of the process in order to minimize risks.
It should be noted right away that self-repair requires caution. The refrigerant circulating inside the system can be dangerous if not handled correctly, and copper is a delicate material that requires care. If you are not confident in your abilities, it is better to turn to professionals. However, for those who have decided to DIY repair, this article will become a detailed guide.
Diagnostics of the fault and selection of a new tube
Before disassembling the unit, you need to make sure that the problem is in the capillary. Often the symptoms of a clogged or broken tube are confused with a freon leak or a compressor malfunction. If the filter drier is hot, but the evaporator is cold only at the inlet, or the system is completely empty, this is a sure sign of circulation problems. Capillary tube has a very small internal diameter, so even microscopic moisture or copper oxides can interfere with operation.
Choosing the right replacement - critical stage. You can't just take any copper tubing and stick it in. The parameters must strictly comply with the factory specifications. Length, inner diameter, and material are critical to the refrigerator's performance. Using the wrong size will cause the compressor to overload or fail to produce the required pressure.
⚠️ Attention: Never use aluminum or steel tubing to replace a copper capillary. Different coefficients of thermal expansion and the impossibility of high-quality soldering will lead to instant depressurization of the system after startup.
When purchasing a new element, pay attention to the packaging: it must be sealed so that moisture and dust do not get inside. The ends of the tube must be plugged. If you see oxides inside or outside, it is better not to use such an element. Standard length capillaries for household refrigerators usually vary from 2 to 4 meters, but exact data should be found in the technical documentation of the model.
Necessary tools and preparation of the workplace
High-quality installation of the tube impossible without specialized equipment. An ordinary DIY kit will not work here. You will need a gas torch with a fine flame, copper solder (usually 5-15% silver content) and flux. Also an indispensable tool will be pipe cutter, which gives an even cut without burrs, and a rolling set for preparing the ends.
- 🔧 Gas burner and gas cylinder (propane-butane or MAPP gas).
- 🔧 Pipe cutter and reamer for chamfering.
- 🔧 Solder (silver or copper-phosphorus) and flux.
- 🔧 Vacuum pump and pressure gauge station.
- 🔧 Nitrogen cylinder for purging (optional, but desirable).
Preparation of the workplace also plays an important role. Ensure good ventilation as soldering produces flux fumes. The surface must be stable and non-flammable. Check the serviceability of all tools in advance. For example, pressure gauges should show zero in a calm state, and the burner should give an even flame. Poor quality tools can ruin expensive components of the refrigerator.
Pay special attention to cleanliness. Any dust that gets inside the system will become the center of moisture crystallization and lead to a new blockage. Therefore, carry out all work on opening the circuit as quickly and carefully as possible. Before soldering, it is recommended to blow the tube with compressed air or nitrogen.
Removing the old capillary and preparing the system
The process begins by disconnecting the refrigerator from the network and completely defrosting it. After this, you need to gain access to the rear wall of the unit. Remove the compressor housing and find the place where capillary tube enters the evaporator and connects to the filter drier. It is usually taped to the refrigerant outlet tube or glued to the wall of the evaporator.
Carefully saw through the capillary near the filter drier. Do not try to pull it out by force - copper is soft and easily deformed. If the tube is mounted in a foamed casing (internal circuit), its extraction requires special care. Often, craftsmen prefer not to pull out the old capillary completely, but bite it and leave it in the body of the refrigerator, installing a new one on top or in parallel.
| Type of malfunction | Symptom | Action |
|---|---|---|
| Clogged capillary | The refrigerator hums, but does not freeze | Replacing the tube and filter |
| Breakage of the tube | You can hear gas escaping, no cold | Finding the break point, soldering |
| Mechanical damage | Dents, kinks | Complete replacement of the area |
| Ice plug | Cyclic operation, ice at the outlet | Nitrogen purging, replacing the filter |
When removing the old element, it is important not to damage the adjacent tubes and walls of the evaporator. If the capillary is glued with aluminum tape, soak the glue with a solvent or gently heat the glued area with a hairdryer. After dismantling, inspect the filter-drier: it must be changed every time the circuit is opened, since it is saturated with moisture from the air.
Technology for inserting and soldering connections
The most crucial moment is how to insert the tube into the refrigerator correctly. The new capillary must be prepared: chamfer the ends, degrease the surface. Insertion into a compressor or filter fitting requires precision. The gap between the walls should be minimal (tension), but without deformation. The seating depth is usually 15-20 mm.
The soldering process requires fast and uniform heating. The burner flame is directed at the connection, heating both parts. When the copper reaches the desired temperature, solder is added. It should flow into the gap under the action of capillary forces, and not just flatter from above. High-quality seam looks smooth and shiny, without sagging or cavities.
⚠️ Attention: When soldering, do not overheat the joint for more than 10-15 seconds. Excessive heat can burn the insulation of the compressor windings or melt solder in other components of the system, creating new problems.
☑️ Soldering control
After soldering all connections, it is necessary to allow the system to cool naturally. Do not cool the seams with water or compressed air - a sharp temperature change will create microcracks in the metal, which will appear later under pressure. Visually inspect the seams: they should be airtight. Any porosity is unacceptable.
Evacuation and refrigerant charging
Just inserting the tube is not enough - the system must be freed of air and moisture. A vacuum pump is used for this. Connect it to the service connection and turn it on for 20-30 minutes. Evacuation removes water vapor, which at low temperatures would turn into ice and clog the new capillary. Residual pressure must be close to absolute zero.
After evacuation, the system is charged with refrigerant. The type of freon (R134a, R600a) and its quantity are indicated on the refrigerator tag. Refueling is carried out strictly by scale, using electronic precision scales. Overfilling or underfilling freon will critically affect the operation of the refrigerator. The compressor can burn out due to water hammer or overheating.
Why can’t you refill “by eye”?
The amount of refrigerant is calculated by engineers with an accuracy of up to a gram. Excess freon will increase the pressure in the condenser, the compressor will work without stopping, and a “fur coat” may form inside the chambers. A lack of freon will lead to poor cooling and overheating of the motor due to insufficient gas cooling of the windings.
After refueling, start the refrigerator and check its operation. The condenser (grid at the back) should be heated evenly, starting from the compressor. The evaporator inside the chamber should be covered with frost evenly. If gurgling sounds are heard or one part of the tubes is hot and the other cold, there may be air left in the system or the amount of freon is incorrect.
Common mistakes and precautions
Beginners often make mistakes that negate all the work. One of the most common is poor cleaning of pipes before soldering. The oxide film on the copper prevents the solder from spreading, forming “pockets” through which gas then escapes. Always use fine sandpaper or a special brush to clean the copper to a shine.
Another mistake is ignoring the replacement of the filter drier. An old filter that has been exposed to air for more than 15-20 minutes is no longer able to effectively absorb moisture. As a result, after a few months of operation, the refrigerator will stop freezing again due to an ice plug in the capillary. Filter drier is a consumable item, it is always changed.
- ❌ Using an open flame near plastic parts of the refrigerator.
- ❌ Soldering under pressure (residual freon).
- ❌ Bend the capillary at an angle of less than 45 degrees (it may collapse).
- ❌ Lack of nitrogen purging if possible (to blow out scale).
It is also worth remembering about security. Freon R600a (isobutane), which is used in many modern models, is explosive when concentrated in air. Therefore, work with it should be carried out in a well-ventilated area, away from sparks and open flames (except for the burner at the time of soldering, when the system is sealed).
FAQ: Answers to frequently asked questions
Is it possible to insert a tube without welding, using only threaded connections?
Theoretically, there are couplings, but they are practically not used in domestic refrigerators due to the risk of leakage. The system operates under pressure and vibration. The only reliable method is soldering with hard or soft solder using flux. Threaded connections in a vibrating environment quickly lose their tightness.
What is the difference between replacing a tube in a No Frost refrigerator and a regular one?
In No Frost systems, the capillary is often built into a foamed circuit or attached to the evaporator, which is difficult to access. Sometimes complete disassembly of the interior or the use of an external line is required. Also in No Frost, the length of the capillary is critical for the operation of the defrost timer and sensors.
How long does it take to cool the soldered seam?
The natural cooling of copper takes several minutes. However, do not try to speed up the process with water. Allow the metal to cool on its own to relieve internal stress. You can check the seam for tightness only after it has completely cooled, otherwise the hot metal may crack from contact with cold gas or water.
Is it necessary to flush the compressor system when replacing the tube?
If the compressor burns out (there was a short circuit), the system must be flushed with nitrogen or a special solvent, since it could get into the tubes acid and combustion products of insulation. If the compressor is working properly and just stood without gas, flushing is not required, vacuuming is sufficient.