A sudden breakdown of a refrigeration unit often becomes an unpleasant surprise, especially when there are perishable products inside. Compressor is the heart of the cooling system, and if it fails, the temperature in the chambers begins to rise, signaling a serious malfunction. In many cases, the cause is overheating, wear of mechanical parts or electrical breakdown of the windings.
When deciding to replace it yourself, you must be aware of the level of responsibility. This is not just replacing a filter, as during defrosting or cleaning, but a complex technical process that requires special tools and skills in working with metals and gases. Replacing a compressor requires mandatory vacuumization of the system and precise dosage of the refrigerant, which cannot be done without specialized equipment.
Nevertheless, for experienced craftsmen and enthusiasts who are ready to purchase or rent the necessary tools, this process is quite realistic. It is important to understand that the success of the operation depends not only on the quality of the new part, but also on strict adherence to the soldering technology and the tightness of the circuit. Any microscopic leak of freon will reduce all efforts to zero.
Diagnostics of the malfunction and selection of a new compressor
Before proceeding with dismantling, you need to make sure that the problem lies in the motor. Often, symptoms similar to a compressor failure can be caused start relay or the thermostat. If the unit hums but doesn't start, or starts for a couple of seconds and clicks when it stops, these are classic signs. However, the final diagnosis is made after testing the windings with a multimeter.
When choosing a new spare part, it is critical to take into account not only the overall dimensions of the seat, but also the technical characteristics. The power, refrigerant type (R134a or R600a) and oil type must fully match the system requirements. Using an unsuitable compressor will lead to rapid failure of both the new motor and the entire refrigeration unit.
⚠️ Attention: Never install a compressor designed for R134a freon in a system where R600a was previously circulated, and vice versa. The oils for these refrigerants have different chemical bases and do not mix, which is guaranteed to cause blockage of the capillary tube.
To accurately select the model, remove the nameplate from the old engine. It shows the type, horsepower (or watts) and size. Also pay attention to the length of the fittings and the location of the tubes - they must match the original so that you don’t have to bend the copper lines, which is extremely undesirable.
Necessary tools and preparation of the workplace
High-quality repairs are impossible without the appropriate equipment. You will need not only a standard set of plumbing tools, but also specific equipment for working with the refrigeration circuit. The main tool will be burner (gas or oxy-acetylene) and a kit for soldering copper pipes.
In addition, a prerequisite is the presence of vacuum pump and a pressure gauge station (manifold) for refilling the refrigerant. Without creating a deep vacuum, moisture and air will remain in the system, which, when frozen, form ice plugs or acid compounds that destroy the compressor from the inside.
Prepare the workplace: it should be well ventilated, since working with open flames and gas requires compliance with safety measures. Provide access to a 220V power source in advance to connect the pump and burner.
- 🔧 A set of open-end wrenches and pliers for dismantling fasteners.
- 🔥 Portable gas burner with a cylinder and solder (phosphorus-copper or containing silver).
- 📏 Manometric manifold, vacuum pump and scales for precise charging with freon.
- 🧹 Pipe cutter, rimmer (for removing burrs) and rags for wiping contacts.
☑️ Checking readiness for repair
Removing the old compressor and preparing the system
Start work only after completely disconnecting the refrigerator from the power supply. Remove the rear panel to gain access to the accessory compartment. The first step is to bleed off any remaining refrigerant. To do this, cut through the copper tube in the area of the capillary system or compressor, allowing the gas to escape.
⚠️ Attention: Although modern refrigerants are considered relatively safe, avoid inhaling freon vapors. Work in a ventilated area or in the open air, since upon contact with an open flame, freon can decompose into toxic compounds.
After bleeding the gas, disconnect the electrical wires from the motor terminals, having previously photographed the connection diagram. Then, using a pipe cutter, cut the suction and discharge tubes, moving 5-10 cm away from the compressor body. This will prevent chips from getting inside the tubes during subsequent soldering.
Unscrew the mounting bolts or nuts holding the compressor to the frame. Some models Atlant refrigerators or Indesit may use rubber shock absorbers, which also need to be removed. Carefully remove the old unit.
Soldering technology and installation of a new unit
Installation of a new compressor begins with preparing the tubes. Remove the transport plugs from the fittings of the new motor only when you begin soldering to prevent oxidation of the copper. If the length of the tubes is not enough, use copper connections, but try to minimize the number of joints.
Be sure to replace filter-drier. This is a disposable element that absorbs moisture and oil breakdown products. The old filter is already saturated with moisture and will not be able to protect the new system. Install a new filter, observing the flow direction indicated by the arrow on the housing.
Nuances of soldering different metals
When soldering copper to copper, phosphorus-copper solder without flux is used. If you need to solder copper to steel (for example, a compressor discharge tube is often made of steel), be sure to use silver solder and flux, since phosphorus-copper solder does not hold steel and cracks when vibrated.
The soldering process requires skill. The burner flame should be directed towards the joint, uniformly heating both parts to be joined. Solder should melt from the heat of the metal, not from direct contact with a flame. After cooling, check the seams visually - they should be smooth, without holes or sagging.
| Connection type | Recommended solder | Melting point | Features |
|---|---|---|---|
| Copper - Copper | Phosphorus-copper | 650-750°C | Self-fluxing, does not require additional flux |
| Copper - Steel | Silver (30-40% Ag) | 700-800°C | Requires the use of flux, high ductility of the weld |
| Aluminum - Copper | Special for Al-Cu | 450-550°C | Complicated soldering, requires careful cleaning of the oxide film |
Evacuation and charging with refrigerant
After assembling the circuit and checking the tightness (pressure testing with nitrogen, if possible), the most important stage begins - evacuation. Connect the vacuum pump to the service connection and start it up. The process should last at least 30-40 minutes for domestic refrigerators.
The purpose of vacuuming is to remove air and, most importantly, water vapor from the system. Water freezes at subzero temperatures, forming an ice block in the capillary tube, which blocks the circulation of the refrigerant. Also, moisture in combination with oil and freon forms aggressive acids.
Refrigerant charging is carried out strictly by weight. The refrigerator label (usually inside the chamber or on the back wall) indicates the exact number of grams. Use electronic scales with a freon cylinder on them. You cannot fill the system by “eye” or by pressure in household refrigerators with a capillary tube - this will lead to incorrect operation.
Turn on the refrigerator and monitor the process. Frost or condensation should appear on the suction tube, and the pressure on the low pressure gauge should stabilize. Excess or lack of freon is equally harmful to the durability of the compressor.
Frequent errors and checking the result
After completing the work and the first start, do not rush to load the products. Let the refrigerator run idle for several hours. Check the temperature in the chambers and make sure that the compressor is operating normally, turning on and off at certain intervals.
One of the common mistakes is incomplete removal of old oil from the system. If the old compressor burned out, carbon and acid could remain in the pipes. In such cases, it is necessary to flush the system with nitrogen, which is extremely difficult to do at home.
Also, technicians often forget to install vibration dampers or bend the tubes incorrectly. Copper is a soft metal, and when repeatedly bent, it loses strength. All bends must be smooth, with a radius of at least three times the diameter of the tube itself.
- ❌ Overheating of the compressor when soldering without cooling with a damp cloth (the valve inside may burn out).
- ❌ Use of the wrong oil for refueling (only specified by the manufacturer).
- ❌ No replacement of the filter drier (guarantee of re-breakdown).
⚠️ Attention: If after replacing the compressor the refrigerator operates but does not cool well, check the capillary tube for blockages. Often, when soldering, oxide or solder gets inside, blocking the cross-section of the tube.
Questions and answers about replacing the compressor
Is it possible to replace an R134a compressor with an R600a?
Theoretically, this is possible with a complete rework of the system, but in practice - absolutely not. These refrigerants have different operating pressures, oil types (mineral vs. synthetic POE), and electrical requirements. An attempt at such a replacement will lead to an explosion or fire.
How much does it cost to replace a compressor yourself?
The cost consists of the price of a new compressor (from 4,000 to 10,000 rubles depending on the model), filter-drier, freon and solder. If you take into account the rental or purchase of a vacuum pump and burner, the amount may exceed the cost of calling a technician if you have no plans to carry out repairs professionally.
Why does a new compressor get hot?
The operating temperature of the compressor housing can reach 70-90°C, which is the norm for many models. However, if it is heated to such an extent that it is impossible to touch, or turns off via a thermal relay after a minute, it means that the circulation of the refrigerant is disrupted (the filter or capillary is clogged) or a leak has occurred.
Is it necessary to flush the system with nitrogen?
If the compressor has simply exhausted its service life (mechanical wear), flushing is not necessary required. If a “breakdown” of the winding occurs (combustion), combustion products and acid remain in the system. In this case, flushing with nitrogen under pressure is mandatory, otherwise the new motor will burn out in a couple of months.