A decrease in cooling efficiency or complete cessation of operation of the refrigeration chamber often indicates a leak. refrigerant. This is one of the most common malfunctions that home appliance owners encounter. Unlike replacing a seal or adjusting a thermostat, this process requires specific knowledge and equipment.
Many DIYers mistakenly believe that simply adding gas to the system through the valve is enough. However, R600a or R134a require compliance with precise proportions and preliminary removal of air. Violation of technology leads to rapid failure of the compressor.
Before taking active steps, you need to make sure that there is no external damage to the tubes and the integrity of the circuit. If you decide to take on the business yourself, prepare for painstaking work with a high level of responsibility. Below we will analyze all the technical nuances of the procedure.
Diagnostics of leaks and preparation of equipment
The first step is always to find the place of depressurization. Freon leak rarely occurs on its own; This is usually preceded by mechanical damage or metal corrosion. A visual inspection often reveals oily spots on the condenser or evaporator tubes, since the oil circulates along with the gas.
To accurately determine the gas exit point, professionals use leak detectors or the soap suds method. If you plan to carry out work at home, make sure the area is well ventilated. Some types of refrigerants are heavier than air and can displace oxygen in the lower part of the room.
You will need to assemble a special set of tools, without which refilling is impossible. The standard kit includes a manifold, vacuum pump, scale and refrigerant cylinder. You will also need tools for soldering copper tubes if you need to replace the filter drier.
- 🛠️ Manometric station with hoses of different colors to control pressure.
- ⚗️ Vacuum pump to remove moisture and air from the system.
- ⚖️ High-precision electronic scales for gas dosage.
- 🔥 Torch or soldering iron for working with copper connections.
⚠️ Attention: Before starting work, be sure to disconnect the refrigerator from the power supply. Working with electrical components and gas under pressure at the same time is deadly.
Do not forget that different models of equipment may require different approaches to diagnostics. For example, in systems No Frost a leak is more difficult to detect visually due to the hidden location of the evaporator.
Choosing the type of refrigerant and its features
Modern refrigerators operate on different types of working substances. The most common are isobutane (R600a) and tetrafluoroethane (R134a). Old models may contain freon R12, which is now prohibited from production, but is still found during repairs.
Isobutane is an explosive gas, which imposes special requirements for the safety of work. Even a small spark when soldering in a confined space can cause a fire. Therefore, when working with R600a maximum caution is required and the absence of open sources of fire within a radius of several meters.
Tetrafluoroethane, in turn, is safe in terms of combustion, but requires higher pressure for condensation. It is strictly forbidden to mix different types of refrigerants. This will lead to a chemical reaction, the formation of acids and rapid destruction of the compressor from the inside.
| Refrigerant type | Evaporation pressure | Safety | Application |
|---|---|---|---|
| R600a (Isobutane) | Low | Explosive | Modern models |
| R134a | Average | Safe | Technology after 2000 |
| R12 | Low | Safe | Old refrigerators |
| R404a | High | Safe | Freezers chambers |
Information about the required type of gas and its quantity can be found on the nameplate located inside the chamber or on the rear wall of the unit. The exact weight in grams is indicated there, deviation from which is unacceptable.
Why can’t you mix freon?
Mixing different refrigerants changes the thermodynamic properties of the mixture. The compressor will not be able to create the required pressure, the oil will lose its lubricating properties, and abrasive particles will form in the system, which will quickly kill the engine.
The process of vacuuming the system
Vacuuming is a critical step that is often ignored by beginners. Removing air and moisture is necessary to prevent ice plugs from forming in the system. Moisture at low temperatures freezes and blocks the capillary tube, stopping circulation.
To carry out the procedure, a vacuum pump is connected to the service fitting. The process should last at least 30-40 minutes for household models. The pressure in the system should drop to a value close to absolute vacuum, which is confirmed by the readings of the pressure gauge.
If, after closing the valve, the pressure gauge shows an increase in pressure, it means that there is still a leak in the system. In this case, it is necessary to repeat the leak search and solder the connections. Only after a successful vacuum test can you proceed to the next stage.
- 🕒 Connect the pump and open the valve for 30-40 minutes.
- 📉 Watch the pressure gauge needle - it should go into the “green” or negative zone.
- 🔒 Close the valve and turn off the pump to check the tightness.
- 👀 Make sure that the arrow does not return within 15 minutes.
Some experts recommend warming up the compressor with a hairdryer during vacuuming. This helps evaporate moisture that may have condensed inside the motor windings after contact with the atmosphere.
⚠️ Attention: Never turn on the compressor without a sufficient vacuum level or the presence of freon. The motor can burn out in a few seconds due to lack of cooling and lubrication.
☑️ Vacuum checklist
Refilling technology and gas dosage
Freon is pumped strictly according to the weight indicated by the manufacturer on the technical tag. The use of eye references or “touch” is unacceptable, as this leads to unstable operation. For accuracy, electronic scales are used on which the cylinder is installed.
The cylinder with refrigerant is turned upside down if the filling is in the liquid phase, or left vertically for the gas phase. In the case of R600a it is often recommended to fill it in the liquid phase through a scale, monitoring every gram. Excess gas increases the condensation pressure and the load on the compressor.
The process is as follows: the cylinder is placed on the scale, the readings are calibrated, then the gas supply valve is opened. As soon as the scales show the desired value minus a few grams (taking into account the gas in the hose), the supply stops. Then the hose is quickly disconnected and the soldering area is sealed.
It is important to bend and solder the service tube quickly to minimize gas escape. Sealing must be perfect, otherwise all the work will go down the drain in a couple of weeks.
Monitoring the operation and setting up the system
After refueling, you need to start the compressor and check the operation of the system. The correct amount of freon is indicated by uniform cooling of the condenser grille at the back of the refrigerator. It should be warm, but not hot to the point of burning.
Pay attention to the operation of the compressor. If it runs continuously and does not turn off, there may be insufficient freon or moisture remaining in the system. If the motor turns off quickly before reaching the set temperature, this may indicate overload or excess gas.
Suction pressure (low side of the pressure gauge) is also an important diagnostic parameter. It varies for different refrigerants. For example, for R134a a pressure of about 0.05-0.08 MPa is considered normal, depending on the ambient temperature.
- 🌡️ Check the temperature in the chambers after 2-3 hours of operation.
- 🔊 Listen to the sounds of operation - there should be no gurgling or hissing.
- ❄️ Assess the uniformity of freezing of the evaporator (if visible).
If you notice that at the outlet of the compressor the tube is too hot, and the return (suction) is cold right up to the compressor itself - this is a sure sign that liquid freon enters the compressor. This phenomenon is called “wet running” and it is detrimental to the mechanics of the motor.
⚠️ Attention: If the compressor is too loud or vibrates more than usual immediately after refueling, stop it immediately. The dosage is probably incorrect or there is air left in the system.
Frequent errors and safety measures
Independent repair of refrigerators is fraught with risks. One of the main mistakes is neglecting to replace the filter drier. The old filter is already saturated with moisture and will not be able to clean the new freon, which will lead to blockage of the capillary with ice in a short time.
Another common problem is the use of the wrong oil. Modern systems use synthetic oils (POE), which are hygroscopic. Moisture getting into such oil turns it into acid, which corrodes the motor windings.
Fire safety is also often forgotten when working with isobutane. Even if the leak seems small, gas can accumulate at the bottom of the room. Be sure to provide a draft before starting to solder any connections.
Do not try to skimp on tools. Cheap Chinese pressure gauges often lie, which leads to incorrect refueling. It’s better to buy a quality tool once or rent it from professionals.
Is it possible to refill a refrigerator without scales?
Theoretically, experienced craftsmen can navigate by the pressure and current consumption of the compressor, but for a beginner this is a recipe for failure. Without scales it is impossible to accurately measure the amount of gas, especially for small dosages of 50-100 grams. An error of 10 grams for a small refrigerator is more than 10% of the norm, which is critical.
How long does it take to completely replace freon?
Professional repairs with leak detection, soldering, vacuuming and refilling take from 1.5 to 3 hours. At home, without experience, this process can take the whole day, especially if you need to search for a hard-to-reach leak.
Why does the refrigerator not freeze after refueling?
There may be several reasons: moisture remains in the system (the capillary is clogged), the amount of freon is incorrectly selected, the filter drier is not replaced, or the compressor has lost performance. It is also possible that the leak was not completely eliminated and the gas came out again.