If your refrigerator Biryusa stopped freezing or the compressor works continuously without cooling the chamber, most likely the problem lies in the refrigerant circulation system. One of the most common causes of such symptoms is a clogged or damaged capillary tube. This thin copper element plays the role of a choke, creating the necessary pressure for the evaporation of freon, and its dimensions are critical for the proper operation of the entire system.
Many amateur craftsmen and even novice specialists often make the mistake of believing that the length of the tube is a secondary parameter. In fact, hydraulic resistance the system directly depends on the length and internal diameter of the capillary. If you install a tube of the wrong size, the refrigerator will work inefficiently, consume more electricity, or the compressor will completely fail due to overload.
In this article we will look in detail at how to determine the required dimensions for various models of refrigerators Biryusa, consider the table of length and diameter correspondence, and also describe the process step by step replacements. You will learn why you can’t just “cut with a margin” and how to correctly calculate the length for refrigerants R134a and R600a.
There is a common misconception that all capillaries are the same. In reality, even for the same refrigerator model, the plant may use different tubes depending on the batch or modification of the compressor. Therefore accurate diagnosis measuring the old part before replacing is a mandatory step in quality repairs.
⚠️ Attention: An incorrectly selected capillary tube length can lead to water hammer in the compressor or its overheating. Always check the markings on the old part.
The role of the capillary tube in the refrigeration circuit
The capillary tube in the refrigerator Biryusa performs the function of a thermostatic valve, but without moving parts. It connects the condenser (where the freon is under high pressure) and the evaporator (where the pressure is low). Passing through a narrow channel, the refrigerant expands sharply and cools, which allows heat to be removed from the products in the chamber.
The length and internal diameter of this tube are selected in such a way as to create the optimal throttling. If the tube is too short, liquid freon may not have time to completely evaporate and will enter the compressor, causing it to break down. If it is too long, the system performance will drop and the refrigerator will not be able to reach the desired temperature.
It is important to consider that modern models Biryusa often use environmentally friendly refrigerants such as isobutane (R600a). They require capillaries with a smaller diameter and longer length compared to older R12 or R134a freons. This is due to differences in the physical properties of gases and the required condensation pressure.
It is also worth noting that the capillary tube is often integrated into the system defrost or heat exchanger. In such designs, it can be soldered to the return line or run inside the housing to prevent condensation from forming outside. Violation of the geometry during replacement can worsen heat transfer.
Factors influencing the choice of size tubes
When selecting a capillary tube for a refrigerator Biryusa you cannot rely only on visual similarity. There are several key factors that determine the technical characteristics of a part. The first and main parameter is compressor power. A more powerful motor requires a larger flow of refrigerant, which dictates the use of a tube with a larger cross-section or shorter length.
The second factor is the type of refrigerant used. As mentioned earlier, freon R600a, popular in new models Biryusahas different flow characteristics than R134a. For R600a, tubes with an internal diameter of 0.5 to 0.7 mm are usually used, while for R134a the diameter can reach 0.8–0.9 mm with a comparable length.
The third factor is the volume of the refrigerator and freezer compartments. Two-chamber models require more careful balancing of the system, since the evaporators can be located at a considerable distance from each other. In such cases, the length of the capillary can vary widely, and an error in calculations will lead to uneven cooling.
Table of capillary tube sizes for Biryusa models
Below is a reference table that will help you navigate the approximate sizes capillary tubes for various series of refrigerators Biryusa. Remember that these values are averaged, and for an accurate repair it is necessary to measure the dismantled part or check the technical documentation of a specific model.
| Model / Series Biryusa | Refrigerant type | Inner diameter (mm) | Recommended length (cm) |
|---|---|---|---|
| Biryusa 6, 8, 10 (old) | R12 / R134a | 0,8 - 0,9 | 250 - 300 |
| Biryusa 11, 14, 16 | R134a | 0,7 - 0,8 | 280 - 340 |
| Biryusa 131, 132, 133 | R600a | 0,5 - 0,6 | 350 - 420 |
| Turk 355, 455 (Side-by-Side) | R600a / R134a | 0,6 - 0,7 | 400 - 480 |
Please note that the length in the table is indicated for standard conditions. If you change the compressor to one of a different capacity, the length of the capillary may have to be adjusted. R600a is characterized by the use of longer and thinner tubes due to the high flammability and low operating pressure of the gas.
In some cases, especially in models with the No Frostsystem, the capillary tube may be part of a complex heat exchange assembly. In such situations, replacing only the straight part of the tube without taking into account the heat exchange coil can disrupt the defrost operation of the evaporator.
Why is length so important for R600a?
Isobutane (R600a) has a higher operating pressure in certain phases of the cycle and a lower vapor density. A tube that is too short will not create a sufficient pressure drop, and the freon will boil ahead of time, without reaching the far corners of the evaporator.
Instructions for replacing a capillary tube
Replacing a capillary tube in a refrigerator Biryusa is a complex process that requires a specialized equipment: vacuum pump, pressure gauge station, torch and tools for copper rolling. Without these tools, high-quality repairs are impossible, since the system must be absolutely sealed and dry.
The first step is to dismantle the old tube. Carefully unsolder the connections at the filter drier and the evaporator inlet. Try not to damage the evaporator itself, as replacing it will cost much more. After dismantling, thoroughly clean the ends of the lines from oxides and old solder.
The next step is to prepare a new tube. Measure the required length, focusing on the measurements of the old part or data from the table. It is important to use oxygen-free copper tubing designed specifically for refrigeration applications. Regular plumbing copper may contain impurities that will quickly lead to a clog.
⚠️ Attention: Before soldering, be sure to blow the tube with nitrogen to remove copper shavings and dust. If debris gets into a thin capillary, it will instantly damage the system.
The soldering process requires skill. Use a minimally aggressive flux and silver solder. The connection of the capillary to the filter drier must be made with special care, since this place is subject to the greatest vibrations. After assembling the circuit, be sure to evacuate the system for 15–20 minutes.
☑️ Checklist for replacing the capillary
Installation errors and their consequences
One of the most common mistakes is ignoring the replacement of the filter drier. When replacing the capillary tube in the refrigerator Biryusa the filter required is replaced with a new one. The old sorbent is already saturated with moisture and will not be able to protect the thin channel of the capillary from the ice plug.
Another mistake is the incorrect depth of the capillary in the evaporator. If the tube enters the evaporator channel too deeply, it may hit a wall or bend, cutting off the freon flow. If it is too small, heat transfer will be disrupted. The optimal depth is usually 20–30 mm, but depends on the design of the specific model.
Often craftsmen forget about the soldering temperature range. Overheating of the junction of the capillary and the filter can lead to burnout of the internal mesh element of the filter or deformation of the capillary itself. Use heat-protective paste or a damp rag to cool adjacent areas when soldering.
Incorrect refrigerant charging after replacement is also fatal. If you replace the capillary with a longer one, the amount of freon may need to be increased, and vice versa. The pressure in the system is not the only indicator; it is important to monitor the compressor current and the temperature of the condenser.
Diagnostics of capillary system faults
How to understand that the problem is in capillary tube, and not in the compressor or freon leak? A characteristic sign of a clogged capillary in the refrigerator Biryusa is the operation of the compressor "pull-in" with overheating, while the condenser (grid at the back) remains cold or warm only at the outlet of the compressor.
In case of partial blockage (for example, ice jam due to moisture) cyclic operation may occur: the refrigerator freezes, then stops, then starts again. This occurs due to the freezing of moisture in a narrow area of the capillary and subsequent thawing when the compressor stops.
For accurate diagnosis, use a pressure gauge manifold. When the compressor is running, the suction pressure will be significantly lower than normal (vacuum), and the discharge pressure will be higher than normal if the capillary is clogged. If the tube is pinched or has a factory defective narrowing, the picture will be similar.
It is also worth checking the filter drier. If it is cold or covered with frost from the entrance to the capillary, this is a sure sign of an obstruction to the freon flow. Visually, the tube may look intact, but inside there may be an oxide film or an oil breakdown product.
What is the length of the capillary tube for Biryusa 133?
For the Biryusa 133 model, operating on R600a freon, the standard length of the capillary tube is usually from 360 to 420 cm (3.6–4.2 meters). The internal diameter is most often 0.5–0.6 mm. The exact value depends on the year of manufacture and the installed compressor.
Can a capillary from another refrigerator be used?
Can only be used if the internal diameter and length match. Capillaries may differ from refrigerators of other brands. It is best to install original tubes Biryusa or universal capillaries with an adjustable length (with a margin), selecting experimentally by pressure and current.
Why does the refrigerator not freeze after replacing the capillary?
There may be reasons several: the length or diameter of the tube was incorrectly selected, the filter-drier was not replaced, moisture or air remained in the system (poor evacuation), or freon leaked during soldering. It is also possible that the problem was not in the capillary, but in the compressor.
How to measure the length of the capillary tube?
The length is measured from the entry point into the condenser (or filter) to the entry point into the evaporator. The tube should not be stretched. If the new tube is longer, the excess is carefully rolled into a ring with a radius of at least 50 mm and secured with a clamp so as not to disrupt the freon flow.
Does the system need to be flushed when replacing the capillary?
Yes, if the reason for the replacement was a burnt out compressor or a serious blockage. Flushing is performed with nitrogen or a special solvent (for example, R141b) to remove oil combustion products and acid from the circuit. Without flushing, the new capillary will clog very quickly.