Replacing the core element of a cooling system is a complex technical process that requires not only special tools, but also a deep understanding of thermodynamics. When compressor stops humming or, conversely, hums constantly without creating cold, the owner is faced with a choice: call a technician or act independently. It is important to immediately realize that the matter is not limited to simply replacing the “hardware”, since the tightness of the circuit and the cleanliness of the system play a decisive role.
Incorrect installation of a new unit can lead to rapid failure of expensive equipment, blockage of the capillary tube with combustion products, or even an explosion of the refrigerant if the technology is violated soldering Modern inverter models require an even more subtle approach than classic linear motors. In this guide, we will analyze all the stages, from dismantling the old unit to the final startup, paying special attention to the nuances that beginners often ignore.
Before picking up the keys, you need to make sure you have all the necessary equipment, since there will be no time to return to the store. Lack vacuum pump or incorrect choice of refrigerant will reduce all efforts to zero. Working with gases under pressure and open fire requires compliance with the strictest safety measures, so it is absolutely impossible to neglect the protection of eyes and hands.
Diagnostics and preparation of the workplace
The first step is an accurate diagnosis, confirming that the problem lies precisely in motor-compressor, and not in the thermostat or start relay. If you hear a clicking sound when you turn it on, the engine tries to start and immediately stalls, or it runs continuously but does not cool, the likelihood of a compressor malfunction is high. Before starting work, you must completely unplug the refrigerator from the power supply and defrost the chambers, removing all products.
The organization of the workspace is critical to the success of the operation. You will need a well-lit area with access to ventilation, since the soldering process and the possible release of residual freon require ventilation. Prepare a stable surface on which you can lay the unit on its side to access the lower technical niche.
⚠️ Attention: Never carry out work to replace the compressor in a closed, unventilated room. The refrigerant is heavier than air and can displace oxygen, creating a risk of suffocation, and flux vapors are toxic.
A multimeter is often used for diagnostics, checking the motor windings for breakdown or breakage. The resistance between the contacts of the starting and working windings must be in a certain range, and the resistance between the housing and the contacts must be infinite. If a breakdown is detected on the housing, further operation is dangerous to life.
Necessary tools and materials
High-quality installation is impossible without a professional set of tools. The basic minimum includes a gas torch (preferably with an oxy-propane or MAPP gas set), a pipe cutter, a roller, a set of wrenches and pliers. Particular attention should be paid to the choice solder: for copper pipes of refrigerators, copper-phosphorus solder without silver content is usually used, as it provides a reliable connection.
The critical element is filter-drier. When the circuit is opened, moisture and air inevitably enter the system, which, when mixed with oil and freon, form acid, which destroys the compressor from the inside. Replacing this element is mandatory for any intervention in the sealed circuit.
- 🛠️ Gas burner with a gas supply for soldering copper tubes.
- 🔧 Pipe cutter and brush for cleaning internal edges pipes.
- ⚗️ Vacuum pump and pressure gauge station for pressure control.
- 🧪 Cylinder with refrigerant (freon), corresponding to the markings on the old compressor.
You will also need a new compressor, completely similar in power, type of refrigerant and geometric seat sizes. The use of universal models is allowed, but requires careful study of the connection diagram and, possibly, replacement of the starting relay.
Removing the old compressor
The process of removing a faulty unit begins with access to the technical area. In most refrigerator models Indesit, Atlant or Beko the compressor is located in a niche at the bottom rear. It is necessary to remove the protective casing, unscrew the mounting bolts and carefully move the motor.
Before cutting the tubes, it is necessary to bleed off the remaining refrigerant. This is done through the process fitting or by carefully cutting the filling tube. After this, you can start cutting through the copper lines. Step back 5-10 cm from the compressor housing to have a margin for subsequent rolling or soldering.
The next step is to turn off the electrical part. Take a photograph of the diagram for connecting the wires to the contact group so as not to confuse phase, neutral and ground when installing a new motor. Remove the starting and protective relay, as well as the capacitor (if it is located separately).
⚠️ Attention: When cutting the pipes of an old compressor, use only a mechanical pipe cutter. The use of a hacksaw for metal is strictly prohibited, since metal shavings will enter the system and are guaranteed to damage the new compressor.
After disconnecting all communications, the compressor is removed from the frame. If the motor is mounted on shock absorbers, they also need to be dismantled, retaining the fasteners to install a new part.
Preparation and installation of a new compressor
Installation of a new unit begins with the preparation of its pipes. If the new compressor has transport plugs, they are removed immediately before soldering. It is important to check whether there is excess nitrogen pressure inside the tubes - this indicates factory tightness.
Installation is carried out in the reverse order of dismantling. The compressor is installed on shock absorbers and secured with bolts. Do not tighten the bolts immediately “all the way”, first tighten them so that the motor fits into place without distortions, otherwise there will be strong vibration during operation.
☑️ Ready for soldering
Now you need to connect the electrical part. Use the photo you took earlier or the diagram on the relay body. Make sure that the contacts fit tightly into the sockets and that the wires do not touch hot parts of the compressor or pipes.
Pay special attention to installation filter-drier. It is mounted at the outlet of the condenser (discharge tube) before entering the capillary tube. There is an arrow on the filter housing indicating the direction of movement of freon - you cannot ignore it, otherwise the system will not work.
Soldering nuances
When soldering copper-steel connections (steel condenser tube and copper compressor tube), use silver solder or special fluxes for dissimilar metals to avoid cracks at the seam.
Soldering of pipelines and sealing
The most critical stage is connecting the copper tubes to the compressor and condenser pipes. For high-quality soldering, the ends of the pipes are cleaned with a brush until shiny, removing oxides. Then the tubes are inserted into one another with a gap of about 0.1 mm, which is necessary for solder to flow.
The burner flame is directed to the joint, uniformly heating both tubes. When the metal is heated to the desired temperature (cherry color), a solder rod is brought to the joint. The molten solder should flow into the gap itself under the action of capillary effect, forming a sealed seam.
| Type of connection | Melting temperature | Type of solder | Features |
|---|---|---|---|
| Copper-Copper | 600-700°C | Copper-phosphorus | Does not require flux, strong connection |
| Copper-Brass | 650-750°C | Silver (30-40%) | Requires flux, high ductility |
| Steel-Copper | 700-800°C | High temperature | Complex connection, risk cracks |
| Aluminum | Special. solders | Aluminum | Requires special. fluxes and skills |
After the seams have cooled (naturally, without water!) it is necessary to carry out pressure testing with nitrogen. The system is filled with nitrogen under a pressure of 15-20 atmospheres. The pressure gauge should not show a drop in pressure for at least 30-60 minutes. This guarantees the absence of microcracks.
Evacuation and charging with refrigerant
Evacuation is a procedure for removing air and moisture from the circuit. It is connected to the process fitting vacuum pump. The process should last at least 30-40 minutes. The residual pressure should be -1 bar (or a value close to it). This will evaporate all the moisture that got into the system during soldering.
After evacuation, the station valve is closed, the pump is turned off, and refueling begins. The refrigerant is charged strictly by weight, using electronic scales, or by pressure, if the liquid phase is used (which is less accurate). The amount of freon is indicated on the refrigerator tag (for example, R600a 50g).
For isobutane (R600a) refilling is carried out only in the liquid phase and with the compressor turned off, since the gas is explosive. Freon R134a possible charge in the gaseous phase with the engine running, monitoring the current consumption.
⚠️ Attention: Technical characteristics and types of refrigerants may vary depending on the year of manufacture and model refrigerator. Always check the type of gas and its quantity on the factory sticker inside the refrigerator compartment or on the back wall, and do not rely on memory.
After refueling, the process pipe is cut and sealed, the motor is started, the uniformity of heating of the condenser is checked and the evaporator is not frozen only in the right places.
Often. asked questions (FAQ)
Is it possible to replace a compressor without a vacuum pump?
Theoretically, some “traditional craftsmen” try to flush the system with freon itself, but this is a gross mistake, without a vacuum pump, moisture will remain in the system, which will freeze in the capillary, causing an ice plug, or form acid with it. with oil, the service life of such a refrigerator will be from several days to a couple of weeks.
Why does the new compressor hum loudly after installation?
There may be several reasons: incorrect installation on the shock absorbers (metal touches metal), the fastening bolts are overtightened, or copper shavings got inside the system during soldering. It is also possible that the unit itself is factory defective or. incompatibility of the model (for example, installation of a more powerful motor).
Is it necessary to flush the system when replacing the compressor?
If the old compressor burns out and acid or carbon deposits form in the system, flushing with a special solvent or nitrogen under pressure is mandatory. If the motor simply stops pumping without burning, it is enough to replace the filter-drier and thoroughly vacuum it. circuit.
What current should a working compressor consume?
Current consumption depends on the power of the motor and usually ranges from 0.5 to 1.2 Amps for household refrigerators. The exact values are indicated on the marking. A significant excess of current indicates an overload, an interturn short circuit or problems with. capacitor/relay.