Many owners of household appliances wonder: what exactly is inside sealed circuit of their refrigerator and why is this substance so important for the operation of the unit? Refrigerant, or, as it is often called in everyday life, “gas”, is a working fluid that circulates through a system of tubes, taking heat from the chamber and releasing it into the environment. Without this substance, the operation of the compressor would be meaningless, since it is the phase transitions of the refrigerant that provide cooling of the products.
Modern models can be charged with different substances depending on the year of manufacture and environmental standards. R134a, R600a and other markings are found in device passports, but not all know how they differ from each other. Understanding the type of gas used is critical when diagnosing problems, as repair and refill methods vary dramatically.
In this article, we will take a detailed look at the chemical composition of refrigerants, their effect on the ozone layer, and human safety in the event of a leak. You will learn why old freons are becoming a thing of the past and what precautions must be taken if you plan to service the equipment yourself.
The principle of operation of the refrigeration circuit
To understand the role of gas, you need to briefly consider the physical process occurring inside the system. The compressor compresses the refrigerant gas, turning it into a liquid under high pressure. In this state, the substance is directed to the condenser (the warm grill at the back), where it gives off heat.
Next, passing through capillary tube, the pressure drops sharply, and the refrigerant turns into gas again, actively absorbing heat from the interior of the refrigeration chamber. This cycle is repeated continuously, maintaining the set temperature.
The effectiveness of this process directly depends on the properties of the substance used. The boiling point of the refrigerant at atmospheric pressure should be significantly below zero, which allows it to evaporate even in the freezer at -18°C. If the properties of the gas change or its quantity decreases, the refrigerator will stop freezing.
⚠️ Attention: The pressure in the system of even an idle refrigerator can reach several atmospheres. Trying to open a sealed circuit without a professional tool can lead to injury or an explosive situation.
Main types of refrigerants: from Freon 12 to R600a
The history of the development of refrigeration technology is a search for a balance between efficiency, safety and environmental friendliness. In different decades, engineers used different chemical compounds.
In older models produced before the mid-90s, Freon 12 (R12)was widely used. It was a reliable and inert gas, but it was later discovered that it was destroying the Earth's ozone layer. Its production was prohibited by the Montreal Protocol.
R12 was replaced by R134a (tetrafluoroethane). It does not harm the ozone, but has a high global warming potential. This gas is still widely used in many models in the mid-price segment.
The current trend is the transition to hydrocarbon refrigerants, such as R600a (isobutane). They are completely environmentally friendly, but require special safety measures during production and repair due to their flammability.
Comparison table of characteristics of popular ones gases
For clarity, let's compare the main parameters of the most common refrigerants that can be found in household appliances of different years of production.
| Gas brand | Chemical name | Environmental friendliness | Flammability |
|---|---|---|---|
| R12 | Dichlorodifluoromethane | Destroys ozone | Non-flammable |
| R134a | Tetrafluoroethane | Safe for ozone | Non-flammable |
| R600a | Isobutane | Environmentally friendly | Explosive |
| R407C | Mixture of gases | Transition option | Non-flammable |
As can be seen from the table, modern environmentally friendly solutions often require compromises in the form of increased care during installation. Isobutane, despite the risks of ignition, it has excellent cooling performance with small filling volumes.
Danger of leakage and impact on health
The issue of refrigerant safety is often surrounded by myths. Many are afraid that a freon leak will instantly poison all residents of the apartment. The reality is more prosaic, but requires attention.
Most modern freons (R134a, R12) are odorless and colorless. In low concentrations typical of a household refrigerator (usually from 30 to 150 grams), they are not toxic to humans. However, with strong concentrations in a closed room, they displace oxygen, which can cause suffocation.
The situation with R600a other. This gas is not toxic, but it is lighter than air and is flammable. Spark from a light switch or a running electric motor can cause a bang if the gas concentration in the niche of the refrigerator reaches a critical level.
⚠️ Attention: If you smell a burning smell or a chemical taste nearby with the refrigerator running, immediately ventilate the room and unplug the appliance. Do not use open fire to find leaks!
Why did old freons smell?
Pure freon itself has no odor. The characteristic “technical” smell that owners of old refrigerators sometimes felt often came from compressor oil or products of decomposition of winding insulation during overheating, and not from the gas itself.
How to determine the type of gas in your refrigerator
If you are planning a repair or just want to know the “stuffing” of your unit, you need to look for this information in technical documents. The device passport is the first source of truth.
If the documentation is lost, pay attention to the sticker located inside the refrigerator compartment or on the back wall of the case. The type of refrigerant and its exact amount in grams will be indicated there. Look for the inscription Refrigerant or Refrigerant.
Also, the type of gas is often duplicated on the compressor nameplate. For example, the marking LBP or HBP indicates the operating mode, and the compatible type of freon is usually written next to it. It is impossible to visually identify gas by the color of the tubes or smell.
When replacing a compressor, technicians often look at the model outlets. Relatively speaking:
- 🔹 Before 1995-1998 - most likely R12.
- 🔹 From 1998 to 2010 - often R134a.
- 🔹 After 2010 - massively implemented R600a.
Features of refilling and repairing the system
Refrigerator repair associated with restoring the tightness of the circuit is a complex technical process. It requires specialized equipment: a vacuum pump, a pressure gauge station and scales.
The process begins with finding a leak. Craftsmen use leak detectors or the nitrogen pressure test method. After eliminating the fistula (usually by soldering), the system must be evacuated. This is necessary to remove moisture and air, which, when mixed with freon and oil, form aggressive acids that destroy the compressor from the inside.
Refilling is done strictly by weight. Underfilling or overfilling refrigerant will lead to incorrect operation: the refrigerator will either freeze slightly, or the compressor will work non-stop, quickly burning. For R600a, filling accuracy is critical down to the gram.
☑️ Stages of professional filling
Frequently asked questions (FAQ)
Is it possible to fill a refrigerator with freon yourself?
Theoretically, it is possible if you have the equipment and skills to solder copper pipes. However, without evacuating the system and accurately weighing the gas, you risk permanently damaging the compressor. In addition, working with flammable gases (R600a) at home is life-threatening.
Why does the refrigerator hum after refueling?
The hum can be caused by several reasons: air entering the system, the wrong amount of oil or refrigerant, or a malfunction of the compressor itself. If a new compressor is humming, it may be of the wrong power.
Is freon from an old refrigerator harmful to the environment?
Yes, old freons (R12) destroy the ozone layer when released into the atmosphere. Therefore, when disposing of old equipment, it is important to take it to specialized points where the gas is pumped out and neutralized, and not just pierced with a sledgehammer in a landfill.
How often do you need to change the gas in a refrigerator?
In a working, sealed refrigerator, the refrigerant is not consumed and does not require replacement for decades. If the gas “runs out,” it means there is a hole (leak) in the system that needs to be found and sealed. Simply “adding gas” without repair is a temporary measure that will not last long.