Sudden silence in the kitchen, replacing the usual hum of a working unit, or, conversely, incessant knocking and vibration are sure signs that the heart of the refrigerator jam. The compressor is the main unit that circulates the refrigerant, and its failure leads to complete inoperability of the equipment. Owners often wonder: is it possible to make the replacement themselves or is it necessary to call a specialist? Theoretically, this is possible, but it requires specific skills and tools.
Before you begin dismantling, you need to objectively assess your strengths and the availability of the necessary equipment. Replacing a motor is not just unscrewing the bolts; it is working with a sealed system, requiring soldering of copper tubes and evacuating the circuit. Errors at any stage can lead to damage to the new expensive component or, in the worst case, to a refrigerant ignition. If you are not confident in your skills with electricity and open flames, it is better to leave this task to the professionals.
However, if you have experience with plumbing or electrical work and are willing to follow strict instructions, this guide will help you understand the process. We will look at the stages of preparation, dismantling the old unit, installing a new compressor and initial startup of the system. It is important to understand that without specialized equipment, such as a vacuum pump and a pressure gauge station, high-quality repairs are impossible.
Fault diagnosis and selection of a new compressor
The first step is an accurate diagnosis, confirming that the problem lies in the compressor, and not in the start relay or thermostat. Often the symptoms of a motor breakdown are confused with the failure of the start-up relay, which is much cheaper and easier to change. If you hear a click when you turn on the refrigerator, the motor tries to start, hums for a few seconds and clicks again, turning off - this is a classic sign compressor wedge or winding breakdown.
For a final check, you need to ring the windings with a multimeter. Normal resistance between the contacts indicates the integrity of the wires, but does not guarantee the mechanical health of the piston group. If the motor hums, but does not start even with a forced voltage supply (through the starting device), and the discharge and suction tubes are cold or one of them overheats, then replacement is inevitable.
⚠️ Attention: If you find that the compressor housing has heated up to a state where it is impossible to touch it, and at the same time the refrigerator does not cool, under no circumstances do not try to turn it back on immediately. Allow the unit to cool completely for several hours to avoid thermal shock to the windings.
Selecting a new unit is a critical step. Compressors vary in power, type of refrigerant, overall dimensions and type of start (RSCR or RSIR). You can’t just buy any motor of similar power. You need to find the markings on the nameplate of the old device and select a complete analogue or a universal model recommended by the manufacturer. For example, to replace old models Atlant or Indesit universal compressors are often used, but they require careful selection for cooling capacity.
Necessary tools and workplace preparation
Replacing a compressor is classified as a complex repair that requires a special set of tools. A regular set of screwdrivers and pliers will not be enough here. You will need a gas torch with a cylinder (propane-butane or oxygen-acetylene), solder for copper (with a silver content of 5-15% or brass) and flux. The use of tin for soldering high-pressure copper pipes is strictly prohibited, as it will not withstand the loads of the system.
A pipe cutter will also be an indispensable tool. It allows you to make a perfectly even cut of a copper tube without the formation of chips that could clog the capillary system. After cutting, the edges of the tubes must be processed with a rimmer or a file to chamfer and remove burrs. To flare the ends of the tubes, if required during installation, you need a rolling machine.
The most important and expensive equipment is a vacuum pump and a filling station with pressure gauges. Without evacuation, air and moisture will remain in the system, which will lead to the formation of ice plugs in the capillary and corrosion of the windings of the new motor from the inside. The process of charging with refrigerant also requires precision, so the presence of a scale for weighing gas or a manifold is mandatory.
- 🔧 Gas burner and fuel cylinder
- 🔥 Solder (silver or brass) and flux
- ✂️ Pipe cutter for copper pipes
- 🔩 Flaring machine and rimmer
- 📉 Vacuum pump and pressure gauge station
- ⚖️ Scales for precise refrigerant charging
☑️ Preparation for repair
Removing the old compressor
The work begins with completely disconnecting the refrigerator from the power supply. The motor is removed from the bottom of the unit, where it is mounted on the frame. Before unscrewing the mounting bolts, it is necessary to cut off the copper tubes coming from the compressor. This should be done at a distance of 10-15 cm from the body in order to leave “tails” for subsequent soldering. The tubes must be cut carefully, without crushing them, so that copper shavings do not get inside.
After disconnecting the tubes from the compressor, the wires from the start relay and the terminal box are unsoldered. It is recommended to photograph the connection diagram before dismantling, so that when installing a new unit you do not mix up the contacts. The old compressor is removed from the shock absorbers and removed from the niche. At this stage, it is important not to damage other elements of the refrigeration unit, such as the condenser or filter drier.
Particular attention should be paid to the filter drier. This is a small copper cylinder installed at the outlet of the capacitor. If there is any depressurization of the system, and cutting off the tubes is precisely depressurization, the filter must be changed. Inside it is zeolite, which absorbs moisture from the air. If you leave the old filter, it will quickly become saturated with moisture and cease to perform its function, which will lead to freezing of the capillary tube.
If refrigerant R134a or R600a (isobutane) was used in the system, special care must be taken. Isobutane is explosive, so all soldering work can be carried out only after thoroughly purging the system with nitrogen or inert gas to displace any remaining flammable gas. Ignoring this rule may result in an explosion when exposed to an open flame.
⚠️ Attention: Residual oil in an old compressor may contain acidic impurities, especially if there was a winding breakdown. Do not allow this oil to come into contact with your skin or eyes, and do not pour it down the drain or onto the ground.
Installing a new compressor and soldering connections
Installing a new motor begins with preparing the seat. It is better to replace rubber shock absorbers (vibration mounts) with new ones, since the old ones become tanned over time and cease to dampen vibration, which will lead to noisy operation of the refrigerator. The compressor is installed on the frame, and the mounting bolts are tightened evenly, without distortions.
The next stage is soldering the copper tubes. This is the most crucial moment that requires skill. The tubes are cleaned to a shine, fittings are put on them (if used) or they are inserted into one another with a gap of about 0.1 mm. The joint is heated with a torch to a dark cherry color, after which solder is applied. The molten metal should flow into the gap under the action of capillary effect, forming a sealed seam.
During the soldering process, it is important not to overheat the tubes, otherwise the copper may burn out. It is also necessary to ensure that the flame does not reach other plastic elements of the refrigerator. After soldering all connections (discharge, suction, process tube), the system is assembled into a single circuit. A Schrader valve is installed on the process tube (usually the shortest) for subsequent evacuation and filling.
Safety precautions when soldering
When working with an open flame, always keep a fire extinguisher at hand. Do not heat tubing near plastic panels or insulation without using heat sink clamps. Be sure to work in a well-ventilated area or outdoors, as flux vapors and possible refrigerant residues are toxic.
After soldering is completed, it is necessary to pressurize the system with nitrogen. This will allow you to identify microcracks or poor-quality seams before vacuuming begins. The pressure rises to 10-15 atmospheres, and the pressure gauge is left under observation. If the arrow does not drop within 30-40 minutes, then the system is sealed and ready for the next stage.
Evacuation and refrigerant charging
Evacuation is the process of removing air and moisture from the refrigeration circuit. A vacuum pump is connected to the Schrader valve. The pump is turned on for 30-60 minutes. The goal is to create a deep vacuum in which the water present in the system as steam will boil and evaporate even at room temperature. This is critical for the longevity of the compressor.
After evacuation, the taps are closed and the pump is turned off. The system is left for a control time (about 1 hour) to check the tightness under vacuum. If the pressure gauge shows an increase in pressure, then there is a leak somewhere, and the process must be repeated, looking for the defect. Only after making sure of the tightness can you proceed to refilling.
Refrigerant refilling is carried out strictly according to the weight indicated on the factory sticker of the refrigerator (usually inside the chamber or on the back wall). The freon cylinder is placed on the scale, and the gas is released into the system through the filling hose. For R134a and R600a weight accuracy is grams. Overfilling or underfilling will lead to incorrect operation of the refrigerator.
| Refrigerant type | Suction pressure (bar) | Boiling point | Features |
|---|---|---|---|
| R134a | 0.8 - 1.2 | -26.3°C | Non-flammable, requires synthetic oil |
| R600a (Isobutane) | 0.4 - 0.6 | -11.7°C | Explosive, requires mineral oil |
| R12 (Obsolete) | 1.4 - 1.6 | -29.8°C | Prohibited for production, used in older models |
| R404A | 2.5 - 3.5 | -46.5°C | Used in industrial and large refrigerators |
⚠️ Attention: Never release refrigerant into the atmosphere. This is harmful to the environment and, in the case of isobutane, creates an explosive concentration indoors. All work on bleeding gas must be carried out through special recovery systems.
First start-up and performance check
After filling, the process tube is sealed. The moment of truth comes - the first launch. Plug in the refrigerator and listen. The motor should run smoothly, without strong vibration or extraneous knocks. During the first minutes of operation, the compressor may heat up - this is normal. After 10-15 minutes, the suction tube (going to the compressor) should become covered with frost or become cold, and the discharge tube should be warm.
Checking the tightness of the seams with a soap solution is a mandatory procedure after startup. Apply soap suds to solder joints. The appearance of bubbles will indicate a leak. If a leak is found, the gas must be vented, the system must be purged and the defective area must be re-soldered. Operating a refrigerator with a freon leak is unacceptable, since the compressor will burn out from overheating without cooling the windings with gas.
The control run of the refrigerator should last at least 24 hours. During this time, the device must reach the set temperature, and the automation (thermostat) must turn off the compressor. If the refrigerator runs continuously and does not turn off, there may be an underfill of freon or a clogged capillary. Overheating of the compressor (when it is impossible to touch it for more than 2-3 seconds) is also an alarming signal.
If all parameters are normal, the refrigerator can be moved permanently place. Make sure that the gap to the rear wall is at least 5-7 cm for normal air circulation around the condenser. Regular cleaning of the condenser grille from dust will extend the life of the new compressor.
Frequently asked questions (FAQ)
Is it possible to replace a compressor without a vacuum pump?
Theoretically, some “masters” use the method of purging with freon itself, displacing air. However, this method is considered artisanal and does not guarantee moisture removal. Moisture in the system is the main reason for the formation of an ice plug in the capillary and the failure of a new motor after a few months. For quality repairs, a vacuum pump is required.
Why is a new compressor louder than the old one?
The noise level depends on the type of compressor and the quality of the installation. If the motor is installed without rubber shock absorbers or they are stiff, vibration will be transmitted to the housing. Noise can also occur if the tubes are installed incorrectly if they touch each other or the housing. Inverter compressors tend to be quieter than conventional ones.
How much does it cost to replace a compressor compared to buying a new refrigerator?
The cost of a new compressor is a significant portion of the price of a new budget refrigerator. If we take into account the cost of work, freon, filter and transportation, repairing an old device is economically justified only in the case of high-quality and expensive equipment (Liebherr, Bosch), the age of which does not exceed 7-10 years. For older models, it is often more profitable to buy a new unit.
Is it necessary to flush the system after the compressor burns out?
Yes, if the compressor burns out with the release of oil into the system (as can be seen by the black color of the leaking oil or soot in the pipes), the system must be flushed with a special solvent or nitrogen under pressure. Acid that gets into the circuit will quickly destroy the insulation of the windings of the new motor.