The situation when the refrigerator stops freezing, and the compressor works without interruption or, conversely, is silent, often leaves the owner with a choice: call a repairman or try to fix the problem himself. One of the most common causes of loss of cold is a leak of refrigerant, commonly called freon. Many people immediately imagine a complex and dangerous process that requires expensive equipment, but a technically competent approach allows you to perform this operation in a garage with a minimum set of tools.
Before taking active steps, you need to clearly understand that simply “refueling” the refrigerator, as is done with cars, is impossible here. The refrigerant circulation system is sealed, and if the gas has escaped, it means that a fistula has formed in the pipes. An attempt to simply add gas without searching for leaks and evacuating the system will only lead to a short-term effect and subsequent failure of the compressor. Therefore, the entire process is divided into troubleshooting, soldering, evacuation and charging. microcrack or fistula in the tubes. An attempt to simply add gas without searching for leaks and evacuating the system will only lead to a short-term effect and subsequent failure of the compressor. Therefore, the entire process is divided into troubleshooting, soldering, vacuuming and refilling.
It is also important to understand the difference between types of refrigerants. Old models used R-12which is now practically not used due to its environmental hazards, while modern units run on R-134a or isobutane R-600a. The latter is especially demanding on the cleanliness of the system and the quality of soldering, since it is a flammable substance. That is why the use of open flame when working with isobutane is strictly prohibitedthat requires the use of alternative soldering methods or special care.
Diagnostics of leaks and preparation of the workplace
The first step is always confirmation of the diagnosis. If the refrigerator is humming, but there is no cold, and there are no hot spots on the rear grille (condenser) or it is only partially warmed up, this is a sure sign of a lack of freon. Sometimes you can hear hissing or see oily spots under the unit - these are places where gas escapes, as freon circulates in the system along with oil. To accurately detect a fistula, professionals use leak detectors, but at home you can use a soap solution, applying it liberally to suspicious joints and pipes.
After localizing the leak site, it is necessary to prepare the work space. You will need easy access to the back of the refrigerator and, in some cases, to the sealed compressor compartment. Before starting work, the unit must be completely defrosted and dried, since the presence of moisture in the system at low temperatures will lead to the formation of ice plugs that will block the capillary tube. It is also necessary to drain the old oil from the compressor if you plan to replace it or if it is heavily contaminated with decay products.
⚠️ Attention: Before starting any work on the pipes and compressor, make sure that the refrigerator is unplugged from the power supply for at least 30 minutes. This is necessary to equalize the pressure in the system and safety in case of depressurization of the circuit.
Preparation of the workplace also includes the organization of good ventilation. Although modern refrigerants are less toxic than their predecessors, their displacement of air in a confined space can cause suffocation. In addition, during soldering, harmful substances will be released, so working in a garage with the door open or on the street is the best option.
Necessary tools and materials for refilling
The quality of the work directly depends on the equipment used. The basic set of a refrigerator repairman includes not only the refrigerant itself, but also tools for working with metal and creating a vacuum. Without vacuum pump it is impossible to refill the refrigerator efficiently, since any moisture or air remaining in the system will lead to an increase in condensation pressure and overload of the compressor.
A collector station (manometric station) is used to connect the cylinder with freon and the vacuum pump. It allows you to control the pressure in the system and see the process of pumping out air. You will also need a pipe cutter, a rolling machine (if you have to change sections of pipes), a set of solder and flux. Modern refrigerators with aluminum tubes may require a special torch or low-temperature solder, since classic brazing can melt thin walls.
The table below shows the main components required for successful refilling:
| Tool/Material | Purpose | Importance |
|---|---|---|
| Vacuum pump | Removing air and moisture from the circuit | Critical importance |
| Gauge station | Pressure control during pumping and filling | High |
| Cylinder with freon | Source of refrigerant of the required brand | Critical important |
| Filter drier | Cleaning freon from moisture and acids | Required upon opening |
| Leak detector | Search for leaks after repair | Recommended |
Special attention should be paid to the choice of flux for soldering. The use of aggressive acid fluxes is unacceptable, since their residues can destroy the tubes from the inside or clog the capillary. It is best to use specialized fluxes for refrigeration equipment or pure borax when working with copper. If you use R-600a, make sure that all connections are tight before turning on the compressor to avoid an explosion of the gas mixture.
The process of evacuation of the refrigeration system
Evacuating is the most important step that beginners often ignore when trying to save time. The essence of the process is to create a deep vacuum inside the refrigerator circuit. This is necessary in order to remove not only air, but also, more importantly, water vapor. Water in the system is deadly: when passing through a capillary tube, where the temperature drops sharply, the moisture turns into ice and completely blocks the circulation of freon.
Technically, the process is as follows: a hose from the vacuum pump is connected to the service fitting (which often has to be welded into the process tube of the compressor) through a pressure gauge station. After turning on the pump, the pressure gauge needle should go into the negative zone (usually -1 Bar or lower). The operating time of the pump depends on the volume of the system and the degree of its contamination, but the minimum time is 30–40 minutes.
☑️ Evacuation checklist
There is a common misconception that vacuuming is only needed to remove air. In fact, at low pressure, water boils at room temperature and evaporates, after which it is pumped out. If you skip this step or perform it poorly, hydraulic hammer or an ice jam will only be a matter of time. Some craftsmen practice the “pushing” method: after vacuuming, they let in a little freon to wash out the remaining contaminants, and vacuum again.
⚠️ Attention: If after 40 minutes of operation of the vacuum pump the pressure gauge needle does not hold and creeps up, then there is a leak in the system. Repeat checking the joints with a soapy solution before continuing work.
Freon charging technology and pressure control
After the system has been prepared and evacuated, the moment of charging comes. The freon cylinder is connected to the central port of the pressure gauge station. Overfilling freon is just as dangerous as underfilling: in the first case, liquid freon can get into the compressor and cause water hammer, in the second, the unit will work with overload without creating cold.
Refilling is done in small portions. The valve on the cylinder opens, and gas under its own pressure begins to flow into the system. At the initial stage, while the compressor is turned off, you can charge about 60-70% of the norm. The remaining amount must be added while the engine is running, monitoring the pressure on the pressure gauge and the temperature of the tubes. The suction pressure must correspond to the boiling point of freon (for R-134a this is approximately 0.1–0.2 bar during normal operation).
Why can’t you fill the refrigerator “by eye”?
The amount of freon is calculated by engineers to the nearest gram. Excess gas leads to the fact that the refrigerant does not boil completely in the evaporator, and the liquid phase enters the compressor. This causes destruction of the valves and jamming of the piston group. Lack of gas leads to overheating of the compressor, as the returning gas cools the motor windings. Therefore, using electronic scales when refueling is the only correct way.
During operation, it is necessary to constantly monitor the current consumption of the compressor using current clamps. If the current exceeds the rated current indicated on the motor tag, the system is overloaded or there are other problems (for example, a dirty capacitor). If the current is below nominal and there is no cold, it is possible that there is not enough freon or the capillary tube is clogged.
Replacing the filter-drier and soldering connections
Any opening of the refrigerator circuit, even short-term, requires a mandatory replacement of the filter-drier. This element is a copper cylinder containing zeolite, a substance that absorbs moisture. Upon contact with atmospheric air, zeolite is instantly saturated with moisture and loses its properties. If you leave the old filter, it will no longer retain water, and after a short time the system will fail.
The process of replacing the filter requires soldering skills. The old filter is cut off or soldered off, and a new one is installed in its place. It is important not to overexpose the burner to the new filter housing, as high temperature can damage the internal sorbent. The direction of flow in the filter is indicated by an arrow and must not be disturbed. After installing the new element, all connections are soldered with hard solder using flux.
When soldering steel tubes, which are often found in the evaporators of modern refrigerators, special solders containing silver or copper-phosphorus solders should be used, if the melting temperature of the base allows. The quality of the seam is checked visually: it must be smooth, without cavities or sagging. Any roughness can become a site for future corrosion or leakage.
Checking the tightness and final startup
After completing all installation work and filling, it is necessary to carry out a final tightness check. Even if everything looks perfect visually, microscopic fistulas can only appear under pressure. To do this, the entire system is pressed with nitrogen or freon itself to operating pressure, and all joints are generously lubricated with soap solution. The appearance of at least one bubble means that the work needs to be redone.
The final launch is carried out with connected instrumentation. The refrigerator is left to work for 2–3 hours. At this time, check the uniformity of heating of the condenser (rear grill), the temperature in the freezer and refrigerator compartments, as well as the cyclical operation of the compressor. The normal mode is when the refrigerator gains temperature and turns off (or goes into standby mode), and then turns on again after a certain period of time.
If the refrigerator is operating in normal mode, the tubes are carefully sealed. The service fitting is cut through at the soldering point, and the cut point is immediately sealed so as not to release the gas. After this, the unit can be installed at a permanent place of operation.
How much freon is needed to refuel a regular refrigerator?
The exact amount is indicated on the technical sticker inside the refrigerator or on the compressor. Typically this value ranges from 30 to 150 grams. The filling accuracy should be ±5 grams, so the use of scales is mandatory.
Is it possible to use car freon for a refrigerator?
Absolutely not. Automotive freons (often with oil additives for air conditioning compressors) have a different chemical composition and properties. Their use will lead to destruction of the seals and failure of the refrigerator compressor.
Why does the refrigerator freeze after refueling, but does not turn off?
This may indicate a freon leak (the fistula has not been completely eliminated), a blockage in the system, or a malfunction of the thermostat. It is also possible that there is too much moisture left in the system, which periodically blocks the capillary.
Is it dangerous to breathe freon vapors?
Freons are heavier than air and displace oxygen. In high concentrations they cause suffocation. In addition, when exposed to an open flame, some types of freons can decompose to form toxic phosgene. You only need to work in a ventilated area.