Many owners of household appliances don’t even think about what’s going on inside the metal grill on the back wall of their kitchen assistant. However, it is there, in the labyrinth of tubes, that the main magic happens - the birth of cold. Understanding what is in the refrigerator radiator is necessary not only for the curious, but also for those who want to properly service their unit or diagnose faults.
A special substance circulates inside a closed circuit, which constantly changes its state of aggregation. It either boils, absorbing heat from the chambers, or contracts, releasing energy into the environment. This endless cycle ensures a stable temperature for your products. Refrigerant is the lifeblood of the refrigeration system, and its properties directly affect the efficiency of the entire device.
Unlike heating systems, where water flows through pipes, here a gas under pressure circulates, which in different parts of the circuit becomes liquid. Modern industry has abandoned the hazardous substances of the past, switching to more environmentally friendly and safe analogues. Knowing the exact composition is important during repairs, since different types of gases are required various equipment for refilling.
Main component: types of refrigerants
The answer to the question of what is in the radiator is simple: there is refrigerant there. For a long time, the industry standard was freons containing chlorine, but due to their destructive effect on the ozone layer of the planet, their production was discontinued. Today you will find completely different substances in household appliances. Most often, modern models use isobutane (R600a) or tetrafluoroethane (R134a).
Isobutane is a hydrocarbon that has excellent cooling performance and minimal impact on the environment. It operates at lower pressure, allowing manufacturers to make tube walls thinner and compressors smaller and quieter. However, this gas has one significant caveat: it is flammable. That is why when repairing such systems, special care is required and the absence of open flame.
Tetrafluoroethane, in turn, does not burn or explode, which makes it safer to use, although slightly less effective compared to isobutane. This gas is often found in older models or in appliances that prioritize safety over energy efficiency. In both cases, the substance circulates in a sealed circuit, and in normal operation it does not disappear anywhere.
- 🧊 R600a (Isobutane): natural gas, high efficiency, low noise level, fire hazard if leaked.
- ❄️ R134a (Tetrafluoroethane): synthetic gas, does not burn, stable, but requires more powerful compressor.
- 🚫 R12 (Freon): obsolete type, prohibited for use in new models due to environmental damage.
⚠️ Attention: Never try to open a sealed circuit or drill radiator tubes yourself. If R600a is inside, contact of gas with air and spark may cause ignition. Repair of such systems is carried out only by specialists with a license and special equipment.
It is worth noting that the amount of gas in the system is strictly dosed by the manufacturer. Typically, the technical label located inside the refrigerator compartment or on the back wall indicates the exact type and grammation refrigerant. Excess or insufficient mass of the substance will lead to incorrect operation: the compressor will overheat and the cold will disappear.
Physical state of the substance in the circuit
The uniqueness of the refrigeration system lies in the fact that the same substance inside the radiator is in different physical states at the same time. The cycle begins with a compressor that compresses the refrigerant gas, turning it into a hot, high-pressure gas. In this state, it enters the condenser - that very black grille at the back.
Passing through the turns of the condenser, the hot gas gives off heat to the room and gradually cools down. When a certain temperature is reached, the condensationoccurs: the gas turns into liquid. It is in liquid form that the refrigerant moves further to the capillary tube, where the pressure drops sharply. After the filter-drier and capillary, the liquid enters the evaporator, where it boils, turning back into gas and taking heat from the products.
Why does gas become liquid?
The transformation of gas into liquid (condensation) occurs not due to cold, but due to high pressure in combined with cooling. The compressor compresses the molecules so much that they are forced to go into the liquid phase, giving off excess thermal energy through the walls of the radiator tubes.
Thus, in the upper part of the rear grille you will find superheated gas, in the middle - a mixture of gas and liquid, and in the lower part - already cooled liquid, ready to evaporate. Understanding this process helps diagnose problems: if the entire grill is hot evenly or, conversely, cold, this is a signal of malfunction.
It is important to understand that the system is under pressure even when it is turned off. The pressure may vary depending on the ambient temperature, but it is always above atmospheric pressure. This prevents air and moisture from entering the circuit, which would be detrimental to the system.
Heat removal system design
The refrigerator radiator, or condenser, is a complex coil made of a steel or aluminum tube. Metal fins or plates are often welded to this tube to increase the heat transfer area. The larger the area of contact with air, the more efficiently heat exchange occurs heat exchange.
In older models, the condenser was taken out separately and attached to the rear wall, so it could be easily cleaned with a brush. In modern built-in and many free-standing refrigerators, the radiator is often hidden. The tubes can be mounted directly into the side walls of the housing or located in the lower part of the unit, near the compressor. In such cases, heat is dissipated through the surface of the case itself.
| Condenser type | Location | Pros | Cons |
|---|---|---|---|
| Static (grid) | Back, on the outer wall | Easy to clean, good heat transfer | Takes up space, makes it difficult to move against the wall |
| Hidden (in the walls) | Inside the side panels | Aesthetic appearance, protection from damage | More difficult to repair, the sides get hot |
| Bottom (at the compressor) | In a niche under the refrigerator | Compact, hidden | Prone to dust contamination, requires blowing |
Regardless of the design, they have the same task - to cool the compressed gas as quickly as possible. To do this, air must circulate freely around the radiator. If you move the refrigerator close to the wall or force the sides with cabinets, the cooling efficiency will decrease and energy consumption increase.
Problems and malfunctions of the radiator
The most common problem that users encounter is contamination. Dust, mixed with grease and pet hair, forms a dense felt on the radiator fins. This “fur coat” works as a heat insulator, preventing the gas from cooling. The compressor is forced to work non-stop, trying to gain temperature, which leads to its burnout.
The second problem is mechanical damage. Thin condenser tubes are easy to break when not in use or when cleaning. If you heard a hissing sound and smelled a specific smell of oil or chemicals, it means that something has happened depressurization. In this case, the gas comes out, and air with moisture is sucked into the system.
- 🔥 Overheating: the radiator is too hot to the touch, the refrigerator hums continuously.
- 💧 Corrosion: rusty smudges on pipes, especially in places of welding or connections.
- ❄️ Ice coat: if part of the radiator is covered with frost and part is dry, the capillary tube may be clogged.
⚠️ Attention: If you notice oily spots on the back wall or floor under the refrigerator, this is a sure sign of a freon leak along with compressor oil. You cannot operate such a device - the compressor will burn out in a matter of hours due to lack of lubrication and cooling.
Sometimes users confuse normal operation with a malfunction. For example, hot sides or a warm jumper between the doors is not a defect, but a feature of the operation of a hidden capacitor. Heat is also removed in these places, and they must be warm while the engine is running.
The process of replacing and refilling the refrigerant
If a leak occurs, simply “topping up” gas, as in a car air conditioner, will not work. The refrigerator system requires a complete vacuum. The technician must first find and eliminate the leak, then connect a vacuum pump to pump out all the air and moisture from the circuit.
Only after creating a deep vacuum is refueling done. The amount of refrigerant is measured to the nearest gram on an electronic scale. Overfilling the gas will cause liquid refrigerant to enter the compressor, causing destruction of the valves. Underfilling will not allow you to reach the desired temperature in the chambers. hydraulic shock and valve destruction. Underfilling will not allow you to reach the desired temperature in the chambers.
Typical filling process:1. Finding and soldering leaks.
2. Installation of the Schrader valve.
3. Vacuuming (minimum 20-30 minutes).
4. Refueling by weight (for example, 65 grams of R600a).
5. Sealing the capillary and checking the tightness.
☑️ Signs of high-quality filling
Modern refrigerants, especially isobutane, require the use of tools with protection (spark-proof). Conventional pressure gauge stations for R12 or R134a may not be suitable for R600a due to the difference in operating pressures and types of oils in the compressor.
Prevention and care of the heat exchanger
For the radiator to serve for a long time, it does not require complex maintenance, but basic hygiene is necessary. Once every six months, it is recommended to move the refrigerator aside and inspect the back wall. If dust has accumulated there, it must be carefully removed with a vacuum cleaner with a soft attachment or a dry brush.
Under no circumstances use sharp objects, scrapers or wet rags to clean metal tubes. Aluminum and thin steel are easily damaged, and moisture can cause corrosion or a short circuit in electrical components located nearby. Dry cleaning is the golden rule of caring for a capacitor.
Also monitor the room temperature. If the refrigerator is located next to a stove, radiator, or in direct sun, the load on the radiator increases many times over. In such conditions, even a working system may not be able to cope with heat removal, and food will begin to deteriorate.
The influence of the type of gas on the environment and safety
Choosing what is located in a radiator, today is dictated not only by physics, but also by ecology. The transition to hydrocarbons (isobutane) was a revolution. These gases have zero ozone depletion potential and minimal global warming potential. However, their natural origin makes them flammable.
Manufacturers compensate for this risk by reducing the amount of gas in the system. If in old refrigerators there could be 200-300 grams of freon, then in modern models with isobutane it is only 40-60 grams. This amount is safe even in the event of complete depressurization in a closed room of a standard kitchen.
Nevertheless, the disposal of old refrigerators must be done correctly. You can't just throw equipment into a landfill and hope that the gas will disappear. Specialized collection points extract the refrigerant and send it for recycling or safe destruction, preventing the release of greenhouse gases into the atmosphere.
Is it possible to refill the refrigerator yourself?
Theoretically, it is possible if you have equipment, but in practice it is extremely difficult and dangerous. You will need a vacuum pump, a scale, a gas cylinder and a soldering torch. An error in dosage or the presence of moisture in the system will lead to compressor failure. Saving on a technician can result in the purchase of a new refrigerator.
Why did the refrigerator stop cooling after defrosting?
Most often the problem is not the gas, but that you turned on the appliance too early. If you start the compressor immediately after defrosting, residual moisture may freeze in the capillary tube, creating an ice block. You need to let the refrigerator stand turned off for at least 4-6 hours.
Is gas from the refrigerator dangerous for people?
Modern gases (R600a, R134a) in low concentrations are not toxic to humans. However, they displace oxygen. In the event of a large leak in a very small, unventilated room, suffocation is theoretically possible, but the volume of gas in a domestic refrigerator is too small for this. The main danger of isobutane is a fire hazard due to a spark.
How to understand that the gas has escaped?
Main signs: the compressor works constantly or does not turn on at all, the condenser (grid at the back) is cold or warm only at the entrance, there is no cold in the chambers, and there may not be uniform frost on the evaporator inside. Only a technician with a leak detector can make an accurate diagnosis.
Is it necessary to change the gas when moving?
No, the refrigeration system is sealed and does not require replacement of the refrigerant during its entire service life, unless there have been breakdowns. Moving, transportation and restarting do not require refueling if the circuit has not been damaged.