The question of what exactly modern and classic Biryusa refrigerators are filled with often arises among owners who are faced with loss of cold. Refrigerant It is the “lifeblood” of the refrigeration machine, and its correct choice is critical for the durability of the compressor and the efficiency of freezing. Unlike old Soviet models, modern units use gases with minimal impact on the ozone layer, which imposes its own limitations on maintenance.
Production in Krasnoyarsk uses different types of substances depending on the year of manufacture and the specific series of the unit. Isobutane i tetrafluoroethane is two main players on the market, and they absolutely cannot be confused due to differences in chemical activity and operating pressures. An error in choosing a substance can lead to failure of an expensive motor-compressor or even to an emergency.
In this article we will analyze in detail the technical characteristics of the gases used, pressure tables for different temperature conditions and nuances that must be taken into account before starting work. Understanding the physics of the process will help you make an informed decision about repairing yourself or calling a specialist with the right equipment.
Main types of refrigerants in Biryusa technology
Historically, the Biryusa plant switched to new environmental standards in stages. For a long time, it was considered the de facto standard R134a, which replaced the aggressive R12. This substance has excellent thermophysical properties, but requires the use of synthetic oils and careful evacuation of the system.
In newer models, especially in the "New Biryusa" series and budget lines of recent years, it dominates R600a. This is isobutane, a natural hydrocarbon gas. It is cheaper, more efficient and more environmentally friendly, but has one critical drawback - high flammability. That is why the operating instructions always contain warnings about not damaging the evaporator tubes.
There is a misconception that you can mix freons or replace one with another simply by changing the pressure. This is not so. Oil, circulating in the system along with the gas, has a different chemical basis: mineral for old types and polyester (POE) for new ones. Mixing oils leads to the formation of an emulsion, which clogs the capillary tube.
⚠️ Attention: Isobutane (R600a) is heavier than air and, if leaked, accumulates at the bottom of the room. If there is a spark, a bang may occur. Working with this gas requires forced ventilation and the absence of open sources of fire.
How to determine the type of freon in your refrigerator
The most reliable way to find out what your refrigerator is filled with is a visual inspection of the technical label. It is usually located on the inside wall of the refrigerator compartment, on the door or on the rear metal panel. Look for the column "Refrigerant" or "Refrigerant".
If the sticker is not readable or is lost, you can determine the type of gas by indirect signs, although this method is less accurate. Models with the system No Frost most often use R134a or mixtures based on it, as they work better in a wide temperature range. Units with a drip defrosting system and one compressor are charged with isobutane in 80% of cases.
- 🔍 Color markings: Tubes for R600a are often yellow or marked, indicating flammability, while R134a is usually marked light blue.
- 📏 Tube diameter: Capillary tubes for isobutane are usually longer and thinner than for tetrafluoroethane due to differences in operating pressure.
- 🔊 Compressor noise: Refrigerators using R600a operate noticeably quieter, since this gas requires less pressure to condensation.
It is also worth paying attention to the type of compressor. If the unit is marked Secop (Danfoss) series NL or similar, it is almost guaranteed to be isobutane. Compressors running on R134a often have a more massive appearance and can be equipped with a forced cooling fan, although not always.
Technical characteristics and pressure tables
For high-quality refueling, it is not enough to know only the type of gas. A critical parameter is pressure in the system, which depends on the ambient temperature and the boiling point of the refrigerant. Incorrect pressure will either lead to underfreezing or to freezing of the suction tube and liquid freon entering the compressor.
Below is a table of comparative characteristics of the two main types of freons used in the Biryusa technique. The data is valid at an ambient temperature of +25°C.
| Parameter | R134a (Tetrafluoroethane) | R600a (Isobutane) |
|---|---|---|
| Boiling point | -26.1°C | -11.5°C |
| Working pressure (low) | 0.6 - 0.8 bar | 0.4 - 0.6 bar |
| Working pressure (high) | 8 - 12 bar | 4 - 7 bar |
| Oil type | Polyester (POE) | Mineral / Alkylbenzene |
| Critical filling mass | High (100-150 g) | Low (30-60 g) |
As can be seen from the table, R600a operates at significantly lower pressures. This means that refilling it requires a more accurate scale, rather than a gauge manifold, since an error of 5-10 grams for isobutane is fatal, while for R134a the tolerances are wider.
When evacuating the system, Water in a system with polyester oil (R134a) leads to the formation of acids that corrode the motor windings. For isobutane, water is dangerous due to the formation of ice plugs in the capillary tube.
Why can’t you fill by pressure?
Filling “by eye” using a pressure gauge is possible only for R12 and then with reservations. For R134a and especially R600a, the pressure is strongly dependent on the condensation temperature. The only accurate method is refueling by weight on a scale with an accuracy of 1 gram.
Signs of a leak and the need for refueling
Before you think about buying a gas cylinder, you need to make sure that the problem is a leak, and not a malfunction of the thermostat or start relay. The sealed circuit of the refrigerator does not require scheduled replacement or addition of freon. If the gas has escaped, it means that a hole has formed somewhere.
Symptoms of a lack of refrigerant usually develop gradually. First, the operating time of the compressor increases, then it starts to turn on more often. At the final stage, the motor is humming, but there is no cold at all, or the freezer is working, but the refrigerator compartment is warm.
- ❄️ Weak cooling: The food in the refrigerator is warm, although the thermostat is turned up to maximum.
- 🔥 Hot condenser: The side walls or rear radiator are barely warm, although must be hot.
- 💧 Lack of cold in the evaporator: When defrosting and turning on, the freezer is not covered with frost evenly.
Often a leak occurs in the foamed part of the housing (internal evaporator) or at the solder points on the rear grille. If you find an oily stain on the tubes, this is a sure sign of depressurization, since freon leaves the system along with the oil.
⚠️ Attention: If, after replacing the compressor or filter-drier, the refrigerator stopped freezing after 2-3 months, most likely an error was made during soldering or vacuuming, and a microcrack formed.
Instructions for safe refilling
The process of refilling the Biryusa refrigerator is a technologically complex operation that requires special tools. You will need: a vacuum pump, a manifold, a scale, a burner (for R134a) or special clamps (for R600a), as well as a new filter drier.
The first step is always to remove any remaining old gas and oil. You can’t just vent freon into the atmosphere, especially R600a. After this, the system is carried out with nitrogen under a pressure of 10-12 bar to search for leaks. Only after making sure of the tightness can you proceed to vacuuming. pressure testing nitrogen systems under pressure of 10-12 bar to search for leaks. Only after making sure of the tightness can you proceed to vacuuming.
☑️ Checklist before refueling
Refill produced strictly by weight. The freon cylinder is placed on the scale, and you monitor the amount of substance pumped. For R600a, the process often occurs through the liquid phase (with an inverted cylinder), but in small portions to prevent water hammer. For R134a, it is also preferable to refill in the liquid phase through a filter-drier or service nozzle.
After refilling, it is necessary to solder the service nozzle (for R134a) or clamp and seal the tube (for R600a). Turn on the refrigerator and check the suction pressure and condensing temperature. The tube leaving the freezer should be slightly cooled, but not covered with frost.
Frequent maintenance errors and their consequences
The most common mistake is trying to fill the refrigerator “by eye” or by analogy with a car air conditioner. The pressure in the refrigeration circuit is low, and pressure gauges often lie. The result is overheating of the compressor and its imminent death.
The second critical point is ignoring replacement filter-drier. This item is inexpensive, but its function is vital. The old filter is already saturated with moisture and will not be able to protect the system from acid and ice plugs. Saving on the filter leads to repeated repairs after six months.
Also, amateur craftsmen often forget about cleanliness. If dust or metal shavings get inside the copper tubes during soldering, it is guaranteed to damage the system. The capillary tube has a microscopic diameter, and any speck will clog it.
Cost of work and feasibility of repairs
If you do not have the skills to solder copper pipes and work with high voltage, self-repair may cost more than a professional one. The cost of freon is low, but the work of the master includes diagnostics, leak detection, soldering, evacuation and warranty.
For old Biryusa models that are more than 15-20 years old, repairs may not be economically feasible if the internal evaporator is broken. In this case, it is easier to consider purchasing a new unit, since modern models are much more economical.
However, if we are talking about a high-quality model with a working compressor, where the leak occurred in an accessible place (for example, a lockring or a tube on the grill has burst), then professional refilling will extend the life of the refrigerator for another 5-7 years.
Is it possible to refill Biryusa refrigerator on your own without equipment?
Absolutely not. Without a vacuum pump, you will not remove moisture and air, which will lead to acid formation and compressor failure. Without scales, you will not get to the filling rate, especially for R600a.
Which freon is better: R600a or R134a?
Both gases are effective. R600a is more economical and quiet, but is a fire hazard. R134a is safer, but requires higher pressure and expensive synthetic oils. The choice depends on the design of the particular refrigerator.
Why does the refrigerator freeze after refueling, but does not turn off?
This is a sign of either underfilling of freon, or (more often) a clogged capillary or filter-drier. It is also possible that air gets into the system due to poor evacuation.
How much does it cost to refill a Biryusa refrigerator at a service?
The price depends on the region and type of refrigerant. On average, work with replacing the filter and refilling R600a costs less than servicing a system with R134a, due to lower gas consumption and simplicity of the process, but requires more qualified technicians.