Compressor failure is perhaps the most serious problem that a refrigerator owner may encounter. It is this unit that is the “heart” of the system, ensuring the circulation of the refrigerant and creating the necessary pressure to cool the chambers. When the unit stops starting, hums without effect, or is simply silent, the user is faced with a difficult technical question: is it possible to replace it independently or is a technician required? The answer to it depends on your skills in working with the tool and understanding of the principles of operation of refrigeration equipment.
The replacement process compressor cannot be called simple, since it requires not only mechanical dismantling, but also soldering work, evacuation of the system and precise charging with freon. Errors at any stage can lead to repeated equipment failure or even an explosive situation in the case of flammable refrigerants. However, for experienced home craftsmen who have the appropriate equipment, this procedure is quite doable and can significantly save on service costs.
In this article we will analyze in detail all the stages of connecting a new compressor, paying special attention to safety and technical nuances. You will learn how to choose the right analogue, prepare the system, solder copper tubes and perform final charging. Remember that refrigerator is a sealed system, and violation of the rules for its maintenance is unacceptable.
⚠️ Attention: Modern refrigerants, such as R600a (isobutane), are explosive when mixed with air. Work to replace the compressor in refrigerators using this gas should be carried out in a well-ventilated area, away from open flames and sparking devices.
Diagnostics and selection of a suitable compressor
Before you begin dismantling the old unit, you need to make sure that the problem lies there. Often, symptoms of compressor failure can be caused by a broken start relay, thermostat, or freon leak. If the engine hums, but does not start, and the relay is working properly, and the motor windings do not indicate a short circuit or break, then replacement is inevitable. It is also important to check for external signs of damage to the housing, such as dents or traces of oil, indicating a leak.
When choosing a new compressor it is critical to consider not only the overall dimensions, but also the technical characteristics. The main parameters are the cooling capacity (measured in watts or kcal/hour), the type of refrigerant (R134a, R600a, R12) and the type of oil used in the system. Using an unsuitable unit in terms of power or type of oil will lead to rapid wear or inefficient operation of the refrigerator.
Pay attention to the markings on the device nameplate. The model, supply voltage, current frequency and permissible operating temperature range are indicated there. For modern models, it is often necessary to select compressors with inverter control, which require connection through a special electronic unit, and not directly through the starting relay.
- 🔍 Check that the supply voltage (220V or 110V) and frequency (50/60 Hz) match the parameters of your electrical network.
- ❄️ Make sure that the type of refrigerant matches the one for which your refrigeration system is designed.
- 🛢️ The type of oil (mineral, synthetic POE, alkylbenzene AB) must strictly comply with the manufacturer's requirements.
- 📏 The overall dimensions and location of the fittings must allow installation in a standard location without complex modification of the pipelines.
⚠️ Attention: Never use compressors designed for R12 (freon) in systems designed for R134a without completely flushing the system and changing the oil, as different types of oils can react chemically, forming an acid that will destroy the insulation of the windings.
Required tools and worker training places
High-quality replacement of the compressor is impossible without specialized tools. A basic home craftsman's kit will not work here, since the work involves high temperatures, pressure and chemically active substances. First of all, you will need a gas welding machine or a high-quality torch with a set of solder and flux for soldering copper pipes. The use of tin-lead solders is unacceptable, since they cannot withstand pressure and vibration in the system.
The second critical element is the vacuum pump and pressure gauge station. Without creating a deep vacuum in the system, it is impossible to remove moisture and air, which, when mixed with refrigerant and oil, form acid and increase condensation pressure. You also need a refrigerant charging kit with accurate scales, since the amount of freon is measured in grams, and a deviation of even 10-20 grams can disrupt the operation of the refrigerator.
Don't forget to prepare tools for mechanical dismantling: a set of open-end wrenches, pliers, side cutters and, possibly, a pipe bender. To protect your hands, use gloves and glasses for your eyes, since soldering can cause solder to splash, and freon when leaving the cylinder can cause frostbite to the skin.
☑️ Preparing to replace the compressor
Removing the old compressor and preparing the system
The first step in the replacement process is to completely disconnect the refrigerator from the power supply. Let the unit stand for several hours so that the oil flows into the compressor and the pressure in the system equalizes. Then you need to carefully unsolder the capillary tube and discharge pipe from the old compressor. This must be done quickly and carefully so as not to damage other elements of the system, such as the filter drier or condenser.
After disconnecting the pipes, the old compressor is removed from the shock absorbers. On some models, it may be welded to the frame or secured with bolts that may have rusted. Use penetrating lubricant to facilitate disassembly. Immediately after removing the old unit, it is recommended to purge the system with nitrogen under pressure to remove oil breakdown products and possible contaminants remaining after combustion of the windings.
An important step is replacement filter-drier. This element is disposable and serves to remove moisture from the system. When the circuit is opened, it becomes saturated with moisture from the air and loses its properties. Installation of a new filter is mandatory, otherwise moisture will quickly damage the new compressor and cause the formation of an ice plug in the capillary tube.
⚠️ Attention: When dismantling the old compressor, never cut through the copper tubes with cutters, as this leads to flattening of the end and chips entering the system. The tubes must be sawed through with a hacksaw or cut with a special pipe cutter, leaving a smooth edge.
Installation of a new unit and soldering of connections
Installation of a new compressor begins with checking the condition of the shock absorbers. If the rubber bushings are worn out or cracked, they must be replaced, as the vibration of the running motor will be transmitted to the refrigerator body, creating a lot of noise. Secure the new unit in place, but do not completely tighten the mounting bolts yet, so that you can move it slightly for convenient soldering.
The soldering process requires special care. Before connecting the pipes to the compressor connections, make sure they are clean and free of grease. The copper must be heated evenly so that the solder flows into the gap due to capillary effect, and does not just stick on top. It is important not to overheat the compressor pipes, as this can damage the internal insulation or deform the seats.
The suction pipe is soldered first, then the discharge pipe. If the design includes a filling fitting, it is also sealed last. After soldering all connections, it is necessary to allow the system to cool naturally. Do not cool the soldering area with water or a damp cloth, as a sharp temperature change can lead to the appearance of microcracks in the seam.
Safety precautions when soldering
When working with an open flame, always keep a fire extinguisher at hand. When heating the tubes, use a heat shield (sheet of metal) to avoid damaging the refrigerator's plastic parts or the interior insulation of the chamber. Plastic melts very quickly, and it will be difficult to restore it.
Evacuation and refrigerant charging
After installing the new compressor and replacing the filter-drier, the most critical stage begins - vacuuming. Connect the pressure gauge station to the service connection and turn on the vacuum pump. The process of pumping out air should last at least 30-40 minutes, and the pressure gauge readings should reach a value of -1 atm (or close to it). This is necessary to remove moisture and air that interfere with the normal operation of the refrigeration circuit.
After creating a vacuum, close the valve on the pressure gauge and turn off the pump. Leave the system under vacuum for 15-20 minutes to check for leaks. If the pressure gauge needle begins to creep up, it means there is a leak in the system, and all seams must be checked with a soap solution. If the vacuum holds, you can start charging.
Refrigerant charging is carried out strictly according to the weight indicated on the label inside the refrigeration chamber or in the technical documentation. A cylinder with freon is installed on a scale, and the refrigerant is released into the system in small portions. For refrigerators operating on R600a, refilling is often done with the compressor running, monitoring the consumption current and the temperature of the condenser, since an overdose of this gas is extremely dangerous.
| Parameter | Description | Importance |
|---|---|---|
| Vacuum | Residual pressure less than 200 microns | Critical important |
| Refill weight | Accuracy +/- 2 grams | High |
| Compressor current | Should not exceed the rated one | High |
| Condenser temperature | Uniform heating throughout length | Medium |
Start-up and performance check
After filling the system, you can perform the first test run. Plug in the refrigerator and listen carefully to the sound of the compressor. It should start with a characteristic click of the relay (if it is electromechanical) and operate smoothly, without vibrations or knocks. In the first minutes of operation, the current consumption may be higher than the rated one, but then it should stabilize.
Check the heating of the condenser grid at the back of the refrigerator. It should warm up evenly, approximately 2/3 of its length from the freon entry point. If only the beginning is heated or, conversely, the entire grate is hot, but there is no cold in the chamber, there may be air left in the system or the capillary tube is clogged. Also check the temperature of the suction tube at the outlet of the evaporator - it should be slightly cool, but not covered with frost.
Leave the refrigerator to work for several hours without loading food. During this time, it should gain temperature and turn off according to the thermostat signal. If the work and rest cycle corresponds to the norm (approximately 15-20 minutes of work and 30-40 minutes of rest), the replacement can be considered successful.
Frequent errors and measures precautions
One of the most common mistakes is neglecting to replace the filter drier. Amateur craftsmen often skimp on this detail, considering it optional. However, moisture that entered the system during installation will inevitably lead to the formation of an ice plug in the capillary after a few days or weeks of operation, and the entire procedure will have to be repeated again.
Another mistake is the use of inappropriate solder or insufficient heating of the soldering area. This leads to the fact that, under the influence of vibration and temperature changes, the seam cracks and freon evaporates. It is also dangerous to overdose on refrigerant: excess freon causes liquid refrigerant to enter the compressor, causing water hammer and destruction of the valves.
Do not forget that modern refrigerators are often equipped with complex electronics that can block the compressor from starting if there are errors in the circuit. If after replacement the unit does not start, check not only the mechanical part, but also the control signals on the start relay.
Is it possible to replace a compressor without a vacuum pump?
Theoretically, some craftsmen use the method of squeezing out air with the refrigerant itself, but this method is extremely ineffective and does not remove moisture. Failure to vacuum is guaranteed to reduce the life of the new compressor and the possible formation of acids in the system. For high-quality repairs, the use of a vacuum pump is mandatory.
Why does a new compressor get very hot?
Strong heating of the compressor housing can be caused by several reasons: insufficient amount of refrigerant (there is nothing to cool the motor with), excess pressure in the system (a clogged condenser or filter), or operation in constant on mode due to heat leakage in the chamber. It is also possible that a compressor of less power was selected than required for a given chamber volume.
Is it necessary to flush the system when replacing a compressor?
Flushing the system with nitrogen or a special solvent is mandatory if the old compressor burned out and released combustion products and acid into the system. If the replacement is planned or the compressor simply stops pumping without burning, it is enough to blow the system with dry nitrogen under pressure to remove moisture and dust.
Which solder is best to use for refrigerators?
For soldering copper tubes in refrigeration systems, it is best to use silver solders (with a silver content of 5% to 45%) or copper-phosphorus solders. They provide a strong and elastic connection that is resistant to vibration. Ordinary tin-lead solder (PLS) cannot be used, since it does not withstand pressure and temperature loads.