A decrease in cooling efficiency or a complete absence of cold in the refrigerator chambers often indicates a critical drop in pressure in the system. This may be due to a natural refrigerant leak or mechanical damage to the circuit. Many owners of household appliances immediately think about refueling themselves in order to save on calling a technician. However, the process refilling freon requires not only special tools, but also a deep understanding of the physics of the refrigeration cycle.
Before taking active steps, you need to make sure that there are no simpler causes of failure, such as a malfunctioning thermostat or a clogged capillary tube. If diagnostics confirm a leak, then simply pumping gas without preliminary preparation will only lead to a short-term effect. In this article we will analyze in detail the technological process of restoring the system's functionality, paying special attention to safety and technical nuances.
It is worth understanding that modern refrigerants, such as R600a (isobutane), are explosive, which imposes additional restrictions on the work. Unlike old freons, they require perfect tightness of connections. Therefore, even if you decide to act on your own, strictly follow the instructions and take the precautions described below.
Diagnostics of leaks and preparation of equipment
The first step is always to find the place of depressurization, since refueling without eliminating the leak is pointless. A visual inspection can often help locate oil stains on the pipes or compressor, as the oil comes out with the gas. For more accurate localization, craftsmen use leak detectors or the method of washing joints, but at home you can limit yourself to a careful study of the visible parts of the circuit.
To carry out the work, you will need a specific set of tools, which are rarely found in ordinary households. Without a vacuum pump and a pressure gauge station (manifold), it will not be possible to perform the task efficiently, since the system must be absolutely dry and free of air.
- 🔧 Pressure gauge station (manifold) with hoses for connection.
- 🌪 Vacuum pump to remove moisture and air from the circuit.
- ⚖️ Electronic scales for accurate weighing of refrigerant.
- 🔥 Torch or soldering iron for working with copper tubes.
- 🛡 Nitrogen cylinder (preferably) for purging and checking pressure.
⚠️ Attention: The use of open fire near an evaporator foamed with polyurethane foam is strictly prohibited without first carefully cutting the housing, since the insulating material is highly flammable.
Particular attention should be paid to choosing the correct type of freon, which is indicated on the compressor nameplate or in the technical documentation of the model Indesit, Atlant or LG. Mixing different types of refrigerants is unacceptable and can lead to compressor failure.
Evacuation technology for the refrigeration system
After eliminating the physical leak (soldering a crack or replacing a filter drier), air and moisture vapor remain in the system. The presence of moisture is especially dangerous, since at low temperatures it turns into an ice plug, blocking the circulation of refrigerant in the capillary tube. That is why the evacuation stage is critically important.
The process begins by connecting the vacuum pump to the service fitting, which is previously soldered into the compressor process tube. The pump is turned on for a long time, usually from 30 minutes to an hour, depending on the volume of the system and the residual moisture.
During pumping, the pressure in the system drops below atmospheric pressure, which causes the moisture to boil and evaporate at room temperature. The pressure gauge at the station will show a value in the minus zone (vacuum), which indicates the removal of gases.
☑️ Evacuation checklist
There is a common misconception that you can simply purge the system with freon, displacing the air. This is a gross mistake, since residual moisture will remain inside and in a short time will cause corrosion of the internal parts of the compressor or blockage of the capillary.
Table of types of refrigerants and their characteristics
Different models of refrigeration equipment require the use of strictly defined types of refrigerants. Their physical properties, such as boiling pressure and chemical reactivity, vary. Below is a comparative table of the main types of freons used in household appliances.
| Freon type | Chemical name | Danger | Pressure (atm) | Application |
|---|---|---|---|---|
| R134a | Tetrafluoroethane | Safe | Average | Modern refrigerators |
| R600a | Isobutane | Explosive | Low | Economical models |
| R12 | Dichlorodifluoromethane | Safe | High | Old Soviet models |
| R404A | Freon mixture | Safe | High | Industrial chambers |
It is important to note that for R600a freon, special spark-proof equipment is required, since the slightest spark during a leak can lead to an explosion. If your refrigerator runs on isobutane, it is better to carry out work outdoors or in a well-ventilated area.
When switching from one type of freon to another (which is sometimes done during deep modernization), a complete flushing of the system and an oil change in the compressor is required, since different refrigerants require different lubricants (mineral or synthetic).
The process of charging refrigerant by weight
The most accurate and professional charging method is dosage by weight. The amount of freon required for a particular model is always indicated by the manufacturer on a technical sticker, usually located inside the refrigerator compartment or on the back wall.
To perform the operation, a cylinder with freon is installed on an electronic scale. The hose from the pressure gauge station is connected to the cylinder, having first purged the connection with a small amount of gas to displace the air from the hose. Then the valve on the cylinder opens and gas is slowly introduced into the system.
The injection process is controlled by the readings of the scales. As soon as the mass has decreased by the value indicated in the passport (for example, 130 grams), the gas supply stops. An excessive amount of refrigerant is just as harmful as an insufficient amount: it leads to compressor overload and poor heat transfer.
What to do if there are no scales?
If there are no electronic scales, experienced craftsmen can navigate by the pressure and current consumption of the compressor, but this method is less accurate and requires a lot of practical experience. The pressure must correspond to the boiling point of freon at a given ambient temperature.
After filling the required volume, it is necessary to let the system operate for 10-15 minutes so that the pressure stabilizes and check the operation of the unit. If necessary, the amount of refrigerant is (adjusted).
Control of pressure and temperature
In parallel with weight control, it is necessary to monitor the readings of the low pressure gauge. For different freons these values will differ. For example, for R134a during normal operation, the suction pressure may be about 0.8-1.2 bar, while for R600a it will be negative or close to zero depending on the temperature of the evaporator.
Also an important indicator of correct charging is the temperature of the compressor housing and condenser (rear gratings). The condenser should be uniformly warm over the entire area, and the compressor should be hot, but not overheating to the point where it cannot be touched.
- 🌡 Checking the temperature of the evaporator: it should be evenly overgrown with frost.
- ⚡ Current control: use an ammeter to check the current of the compressor windings (should not exceed the nominal value).
- 👂 Acoustic control: absence of gurgling and extraneous noise in the tubes.
If after refueling the refrigerator began to freeze, but after a while it stopped again, an ice plug may have formed. This indicates that the evacuation stage was carried out poorly and moisture remained in the system.
Completing work and sealing
When the optimal amount freon is charged and the operation of the system is checked, it is necessary to hermetically seal the process fitting. This is done using a gas torch or a powerful soldering iron. The copper tube is pinched with pliers a few millimeters from the compressor, and the pinched area is sealed.
After soldering, be sure to check the connection for leaks using a soap solution. The appearance of bubbles will indicate a soldering defect, which must be eliminated immediately. Then the tube is cut off, leaving a small stump.
⚠️ Attention: Soldering must be done quickly so as not to overheat the compressor windings, since high temperature can damage the varnish insulation of the wires inside the motor.
The final stage is to clean the back wall of the refrigerator from traces of soldering and install the unit in its original place. It is recommended to let the refrigerator stand turned off for 2-3 hours after transportation if it was tilted so that the oil flows into the compressor crankcase.
Frequently asked questions (FAQ)
Is it possible to fill a refrigerator with freon without a vacuum pump?
Theoretically, you can try to purge the system with freon itself, displacing the air, but this is highly not recommended. Moisture will remain in the system, which will quickly lead to the formation of an ice plug in the capillary tube and failure of the compressor. Evacuation is a mandatory step.
How often do you need to change freon in the refrigerator?
Freon is not a consumable item and does not require scheduled replacement. If there are no leaks in the system, one filled volume is enough for the entire service life of the refrigerator (10-15 years or more). Refilling is required only when repairing after a leak.
Why does the refrigerator freeze after refueling, but does not turn off?
This may indicate several problems: a lack of freon, a blockage in the system, a malfunction of the thermostat or defrost sensor. Also, the reason may be a violation of the tightness of the door seal, due to which heat constantly enters the chamber.
Is it dangerous to breathe freon vapors?
In high concentrations, most freons can cause suffocation, as they displace oxygen. Some species release toxic substances (phosgene) when heated. Therefore, work should be carried out in a ventilated area, avoiding direct inhalation of the gas stream.