What are refrigerator compressors charged with: types of refrigerants

A modern refrigerator is a complex thermodynamic system, the core of which is compressor. It is this unit that is responsible for the circulation of the working substance in a closed circuit, ensuring heat removal from the internal chamber of the device. Many owners of household appliances mistakenly believe that there is air or some kind of universal gas inside the system, but in fact special chemical compounds are used, known as freons. refrigerants or freons.

Understanding what exactly compressors charge is critical important not only for professional craftsmen, but also for any user who wants to extend the life of their equipment. Different equipment models require strictly defined types of gases, and mixing them or replacing one type with another without reconfiguring the system often leads to breakdown. In this article we will analyze in detail what substances are used in the refrigeration industry, how they differ and why it is important to comply technical regulations during maintenance.

In addition, knowledge of the composition of the refrigerant helps to correctly assess the risks of pipeline damage or odor. Some modern gases are flammable, others are inert, and the approach to their operation is radically different. Let's dive into the technical details so that you can confidently navigate the characteristics of your refrigeration unit.

The principle of operation and the role of the refrigerant in the system

To understand why specific substances are used to charge the compressor, it is necessary to briefly consider the physics of the process. Refrigerant is a working fluid that transfers thermal energy. While in the evaporator, it boils at low temperatures, actively absorbing heat from the products. Then, in a gaseous state, the substance enters the compressor, where it is compressed and heated.

In the condenser, usually located on the rear wall, the gas releases the accumulated heat to the environment and turns into a liquid state. The cycle closes when the liquid, through capillary tube or the throttle, enters the evaporator again. The efficiency of this process directly depends on the thermodynamic properties of the selected gas, its ability to phase transitions and heat capacity.

It is important to note that the compressor does not create cold, it only pumps heat. If the system does not have enough freon or its properties do not correspond to the design parameters of the compressor, the operating efficiency will drop to zero. The motor may begin to work with overload, trying to compensate for the lack of pressure, which will ultimately lead to thermal overheating of the windings.

Main types of refrigerants: from R12 to R600a

The history of the development of refrigeration technology goes back more than a century, and during this time the chemical composition of the refilled substances has changed several times. The first models used ammonia and sulfur dioxide, which were toxic and a fire hazard. Later, the industry switched to freons, which were considered safe, but later it turned out that many of them destroy the ozone layer.

Today, three main types of refrigerants can most often be found in household refrigerators. First on the list is R134a (tetrafluoroethane). This is a colorless gas that replaced ozone that destroys ozone R12. It is non-toxic, does not burn and has excellent refrigeration properties, but requires the use of synthetic oils to lubricate the compressor.

The second, and most popular in modern models, is R600a (isobutane). It is a hydrocarbon gas that has excellent cooling performance and minimal environmental impact. However, it has one significant nuance - it flammable. That is why when repairing units using isobutane, special care and compliance with fire safety rules are required.

There is also a list of characteristics by which gas is selected for a specific model:

• 🧊 Temperature boiling point - determines how low the temperature the evaporator can produce.
• 🔥 Fire hazard —a critical parameter that affects the design of the electrical part of the refrigerator.
• 🌍 Environmental friendliness —impact on the ozone layer and global warming potential (GWP).
• 💧 Hygroscopicity —ability absorb moisture, which affects the requirements for cleanliness of the system.

Technical features of compressors for different gases

A compressor is not just a pump, it is a high-precision mechanism designed to work with a specific environment. The difference between compressors for R134a and R600a lies not only in markings, but also in design. For example, motor-compressors for isobutane often have a lower capacity in terms of the volume of pumped gas, since the specific refrigeration capacity of R600a is higher.

Another important aspect is the type of oil used. Mineral oils, which have been used for decades in older freon systems, are not suitable for new synthetic refrigerants. For R134a polyester oil (POE) is required, which is highly hygroscopic. This means that it instantly absorbs moisture from the air, so such compressors cannot be kept open even for a few minutes.

⚠️ Attention: An attempt to charge a compressor designed for R134a with R12 or R600a refrigerant without completely overhauling the system and changing the oil will lead to jamming of the piston group and combustion of the motor.

The discharge and suction pressure also differs. Compressors for hydrocarbons operate at lower pressures, which reduces noise and vibration, but requires better sealing of the engine shaft to prevent flammable gas from leaking out. The design often uses additional intrinsic safety measures for the starting relay.

For visual distinction, craftsmen often look at the tag or color marking of the tubes, although you cannot rely on color alone. The most reliable way is to check technical data sheet or the markings on the body of the unit itself. An error in choosing the type of compressor when replacing can cost the owner expensive repairs.

Comparison table of refrigerant characteristics

For a visual comparison of the properties of various substances used to charge compressors, we provide a summary table. This data will help you understand why there was a transition from one type of gas to another and what advantages each of them provides.

The table shows that R600a has a higher boiling point at atmospheric pressure, but in the system it operates under vacuum or low pressure, which makes it very efficient. However, its flammability imposes restrictions on the amount of refilled substance - usually it is only 30-60 grams, while R134a can be refilled in a volume of 100-200 grams or more.

Good old R12, which could be found in Soviet-made refrigerators, is completely prohibited for use in new devices due to its destructive effect on the planet’s ozone layer. Finding a new compressor for this gas is now almost impossible, and its use is considered an environmental crime in many countries.

Refilling process and necessary tools

Refilling a refrigerator compressor is a technological process that requires special equipment and skills. You cannot simply “add gas” from a cylinder, as is done with lighters. The process begins with finding and eliminating leaks, since the refrigerant is not consumed during operation, but circulates in a closed circuit.

To carry out the work, the technician will need a vacuum pump, a pressure gauge station (manifold), high-precision scales and a set of pipe cutters. First, the system is evacuated to remove air and moisture. This is a critical stage: residual moisture in the system will turn into an ice plug in the capillary or react with the oil, forming acid. R134a will turn into an ice plug in the capillary or react with the oil to form an acid.

Next, refueling is carried out. The amount of refrigerant is determined strictly by scale, accurate to the nearest gram. Overfilling or underfilling will lead to incorrect operation. Some modern models use the filling method according to pressure and current consumption of the compressor, but the weight method remains the reference.

Particular attention is paid to the filter drier. When opening the circuit to replace the compressor or eliminate a leak, this element must be replaced with a new one. The old filter is already saturated with moisture and will not be able to protect the system from the formation of ice plugs and acid deposits inside the windings.

Symptoms of freon shortage or leakage

How can an ordinary user understand that the compressor has stopped receiving the required amount of refrigerant? The system itself gives signals that should not be ignored. The first and most obvious sign is insufficient cooling. The food in the chamber begins to deteriorate, the ice in the freezer melts or does not form at all.

The second symptom is the engine operating mode. If there is a freon leak, the compressor may work without stopping, trying to reach the set temperature. This leads to strong heating of the motor housing. In other cases, with a complete leak, the refrigerator may not turn on at all if there is a thermal protection relay in the circuit, which opens the contact when overheated.

It is also worth paying attention to the following signs:

• 🔊 Strangers sounds - gurgling, hissing or whistling may indicate gas escaping through a microcrack.
• 🌡️ Condenser heating —the grill on the back wall should be warm evenly. If it is cold or only partially hot, the circulation is impaired.
• 💧 Bloating of the walls — in rare cases, when using foaming agents in the housing, a leak can lead to local swelling of the panels.

⚠️ Attention: If you smell a sweet chemical or gas smell in the kitchen, immediately ventilate the room and do not turn on electrical appliances. Although modern freons in small doses are not poisonous, they displace oxygen, and isobutane is explosive.

Is it possible to refill the refrigerator yourself?

Theoretically, it is possible if you have the equipment and soldering skills. But without vacuuming, the system will quickly fail. Moisture that gets inside will create acid that will corrode the compressor windings from the inside within a few months. Saving on a repairman will lead to the purchase of a new refrigerator.

Safety measures and environmental standards

Working with refrigerants is regulated by strict international agreements, such as the Montreal and Kyoto Protocols. Unauthorized release of freon into the atmosphere is prohibited. Therefore, when making repairs, professionals use recuperators - devices for collecting waste gas so that it does not enter the atmosphere.

For a home handyman, the main rule is safety. When working with R600a it is necessary to exclude any sources of spark. You cannot solder pipes if there is gas left in the system - it must be vented in a well-ventilated area away from open flames. Many people forget that even a spark from a start relay or static electricity can ignite a mixture of gas and air.

In addition, refrigerants are heavier than air and can accumulate in the lower part of the room, displacing oxygen. Prolonged inhalation of freon vapor causes suffocation, dizziness and heart rhythm disturbances. Therefore, any manipulations with disconnecting the circuit should be carried out only in the presence of forced ventilation.

Equipment manufacturers are switching to new, even safer mixtures. Therefore, before purchasing spare parts or attempting repairs, check the information with official sources of the manufacturer of your refrigerator model.

Frequently asked questions (FAQ)

Is it possible to fill the refrigerator with ordinary air?

Absolutely not. Air contains nitrogen, oxygen and moisture. Oxygen will oxidize the oil and metal from the inside, moisture will freeze in the capillary, blocking circulation, and nitrogen will create excess pressure. The compressor will burn out or explode.

How can I find out what kind of freon is in my refrigerator?

Look at the technical sticker. It is usually located inside the camera (on the side wall or ceiling) or on the rear wall of the case. Look for the “Refrigerant” or “Refrigerant” field, where the code will be indicated, for example, R600a.

Why can’t you mix different types of freon?

Different refrigerants have different chemical properties and require different oils. Mixing will lead to an unpredictable chemical reaction, the formation of acids, sediment and complete loss of refrigeration effect. The system will not work.

Is R600a freon dangerous for humans?

Isobutane itself is not toxic, but it displaces oxygen, which can cause suffocation in a confined space. The main danger is its explosion hazard at concentrations in air from 1.3% to 8.5%.

Is it necessary to change the compressor if a leak occurs?

Not always. If the leak occurred in the external circuit (pipes, evaporator) and the compressor did not overheat, it can be left. But if the system has been opened for a long time or moisture has gotten inside, it is better to replace the compressor and filter-drier.