The appearance of condensation on the back wall or a complete lack of cold often makes owners of household appliances think about a lack of refrigerant. Many people mistakenly believe that the problem can be solved by simply “pumping” gas, similar to refilling a car air conditioner. However, refrigeration circuit is a closed, sealed system, where a leak of the working fluid indicates a violation of the integrity of the pipelines.
Before looking for a gas cylinder, you must clearly understand: it is impossible to simply add a substance inside the system without breaking the seal. The process of restoring the functionality of the unit Indesit, Atlant or Bosch requires not only the presence of specific equipment, but also strict adherence to technological safety standards. Ignoring these rules can lead to compressor failure or even fire.
In this article we will analyze in detail the physical aspects of the operation of the cooling system, the stages of leak detection and the refueling procedure itself, which is almost impossible to perform at home without a professional set of tools. Understanding these processes will help you make an informed decision about calling a technician or doing the repair yourself.
Operating principle and types of refrigerants
The functioning of any household refrigerator, be it an old Soviet one ZIL or a modern one LG with the No Frost system, is based on cyclic change in the aggregate state of the working substance. The gas circulating inside the copper tubes, when compressed by the compressor, heats up and passes into the liquid phase in the condenser, releasing heat to the environment. Then, passing through capillary tube, the liquid expands sharply in the evaporator, taking heat from the refrigerator chambers.
In modern models, the following types of gases are most often used:
- 🧊 R134a —the most the widespread safe freon, which replaced the ozone-active R12, does not burn and is not toxic under normal conditions.
- ❄️ R600a (isobutane) is an environmentally friendly hydrocarbon that is highly efficient, but is explosive when mixed with air.
- 🔥 R12 —obsolete a refrigerant found in technology before the 2000s, the production of which is prohibited due to harm to the ozone layer.
⚠️ Attention: Using the wrong type of freon (for example, charging R134a instead of R600a) will lead to immediate failure of the compressor and may cause an explosion due to differences in operating pressure and types used oils.
It is critical to understand that each type of gas requires a different type of compressor oil and has unique pressure characteristics. Mixing different brands of refrigerants is unacceptable, as this changes the thermodynamic properties of the mixture and can lead to blockage of the system or destruction of the rubbing pairs of the compressor.
Diagnostics: is there really a leak?
Before embarking on complex manipulations with gas, you need to make sure that the problem lies precisely in a leak and not in a malfunction thermostat, start relay or clogged capillary system. If the compressor runs continuously, but there is no cold, or it turns on for short periods of time with a characteristic click, this may indicate various breakdowns. Primary diagnosis begins with a visual inspection.
Pay attention to the following signs:
- 👀 The presence of oily spots on the rear grille or inside the freezer, which indicates a place of depressurization.
- 🌡️ Uneven cooling: one part of the evaporator is covered with frost, while the other remains warm.
- 🔊 Change in the sound of the motor: the appearance of hissing or gurgling, which was not there before.
To accurately confirm a leak, technicians use an electronic leak detector or a soap solution. At home, you can apply soap foam to suspicious areas of the pipeline while the compressor is running. The appearance of bubbles will indicate where the gas is escaping. However, microcracks in the foamed part of the case (where the evaporator is located) cannot be detected using this method; disassembling the case or using nitrogen under pressure is required.
Required equipment for refilling
Performing work to restore the refrigerant level requires a specialized tool, which is rarely found in the arsenal of a home craftsman. The standard kit includes not only a gas cylinder, but also means for creating a vacuum, which is a mandatory step. Without removing moisture and air from the circuit, the refrigerator will not work.
The basic set of equipment is as follows:
- 🛠️ Vacuum pump —a device for pumping air and water vapor from the system, creating a deep vacuum.
- 📊 Gauge station —allows you to control the pressure when refueling and evacuation.
- ⚖️ Electronic scales —necessary for accurate dosing of gas, since filling is carried out by mass and not by pressure.
- 🔥 Burner and solder - for sealing the service fitting and eliminating any leaks found.
⚠️ Attention: An attempt to fill “by eye” or by pressure without evacuation will lead to the formation of an ice plug in the capillary tube and a water hammer in the compressor.
You will also need a service valve (fitting), which cuts into the process tube of the compressor. The use of homemade adapters or nipples from car tires is unacceptable due to the risk of depressurization of connections under high pressure. All components must be designed to work with a specific type of freon and oil.
Step-by-step instructions for restoring the circuit
The refilling process is a continuation of repair work to eliminate leaks. If you have found the damage and soldered it, or replaced the evaporator, the next step is to prepare the system. First, nitrogen pressure testing is performed to check the reliability of soldering. Only after making sure of the tightness can you proceed to evacuation.
The sequence of actions looks like this:
- Inserting the service fitting into the process tube of the compressor.
- Connecting the hoses of the pressure gauge station to the fitting and the vacuum pump.
- Turning on the pump for 20-30 minutes to remove moisture and air.
- Closing the valve and turning off the pump to control vacuum stability.
- Filling the calculated mass of refrigerant through the liquid phase.
☑️ Checklist before startup
The most important point is to control the amount of substance added. The exact weight is always indicated on the compressor nameplate or in the technical documentation, for example 130 g ± 5 g. Exceeding the norm will lead to increased pressure and overload of the motor, and a deficiency will lead to insufficient cooling. Refueling is done with the unit running in small portions at intervals to stabilize the pressure.
Table of parameters and types of oils
For correct operation of the system, it is necessary not only to know the type of gas, but also compatibility with the oil in the compressor. Different refrigerants require different lubricants. Below is background information on the main types of freons.
| Freon type | Oil type | Boiling pressure (atm) | Features |
|---|---|---|---|
| R12 | Mineral | 1.0 | Toxic upon combustion, prohibited |
| R134a | Synthetic (POE) | 1.6 | Hygroscopic, afraid of moisture |
| R600a | Mineral/Alkylbenzene | 0.8 | Explosive, small filling |
| R404a | Synthetic (POE) | 4.5 | Used in freezers |
Please note that synthetic oils used with freon R134a, are highly hygroscopic, that is, they actively absorb moisture from the air. Therefore, the contact time of an open system with the atmosphere should be minimal. R600a is characterized by a low filling weight (only 50-70 grams), which requires the use of high-precision scales.
What will happen if the technology is violated?
If you do not create a vacuum, the remaining moisture will freeze in the capillary tube, blocking the freon flow. The compressor will run idle, overheat and burn out. Moisture also reacts with oil, forming acid, which corrodes the motor windings from the inside.
Typical errors and safety precautions
Independent repair of refrigeration equipment involves serious risks. One of the most common mistakes is ignoring fire safety rules when working with freon R600a. This gas is heavier than air and, if leaked, accumulates in the lower part of the room, forming an explosive mixture. Any spark from a relay or socket can cause a pop.
The main risks during unprofessional refueling:
- 🔥 Air entering the system, which causes oil oxidation and the formation of acids.
- ❄️ Formation of an ice plug that blocks circulation refrigerant.
- 💥 Depressurization of solder joints due to incorrect selection of solder or temperature.
⚠️ Attention: By opening the foamed part of the housing to look for a leak in the evaporator, you are breaking the thermal insulation. It is impossible to restore the factory properties of polyurethane foam at home, which will lead to constant excessive energy consumption.
The error of incorrectly selecting a compressor during replacement is also common. The power of the new engine must match the volume of the evaporator and condenser. Installing a more powerful motor “by eye” will lead to the fact that it will often turn off the thermostat without having time to freeze the food, or, conversely, work without stopping.
When you need to call a specialist
Despite the theoretical knowledge, in practice most users are faced with the impossibility of performing high-quality repairs with their own hands. The specifics of the work require not only tools, but also experience in reading the “behavior” of the refrigerator in terms of current consumption and temperature in different parts of the circuit.
Contacting a professional is necessary in the following cases:
- 📉 A leak has occurred in the foamed part (inside the case), which requires complex diagnostics.
- 🔧 Required replacing the compressor or filter-drier.
- ⚡ There is no certainty about the type of refrigerant or oil used.
The technician has equipment for vacuuming and filling on scales, as well as a guarantee for the work performed. The cost of calling a specialist is often lower than purchasing expensive equipment for a one-time refill and subsequent repair of a damaged compressor.
Is it possible to refill a refrigerator with ordinary automobile freon?
No, you can’t. Car air conditioners operate on R134a freon, but the oils and pressures in the systems may differ. Moreover, household refrigerators often use R600a, which absolutely cannot be mixed with automotive analogues. Using the wrong gas will cause damage.
Why did the refrigerator begin to work worse after refueling?
Most likely, the vacuum technology was broken, and air or moisture remained in the system. It is also possible that the amount of refrigerant was incorrectly selected (overdosing or underfilling). The exact dose is indicated on the compressor nameplate and must be observed to the nearest gram.
How often should freon be added to a working refrigerator?
In a working, sealed refrigerator, freon is not consumed and circulates in a closed circuit for decades. If the gas goes somewhere, then there is a leak in the system that needs to be found and fixed. Simply “topping up” gas once a year is the wrong approach, leading to breakdown.
Is it dangerous to breathe freon vapors?
Yes, it is dangerous. Although many modern freons are considered non-toxic, in a confined space they displace oxygen, causing asphyxiation. When heated with an open flame, freons can decompose into phosgene, a chemical warfare agent. You only need to work in a well-ventilated area.