The situation when the refrigerator suddenly stops cooling, and the compressor is silent or works intermittently, always takes you by surprise. In most cases, this indicates a critical malfunction of the main unit, which is often called the heart of the refrigeration system. Independent replacement of this unit is a complex technical process that requires not only special knowledge about the design of refrigeration units, but also the presence of specific equipment. compressor, which is often called the heart of the refrigeration system. Replacing this unit yourself is a complex technical process that requires not only special knowledge about the design of refrigeration units, but also the availability of specific equipment.
Before proceeding with the dismantling of the old engine, it is necessary to carry out a thorough diagnostics. Often, symptoms indicating a compressor failure can be caused by a faulty start relay or thermostat. If you are convinced that the problem is in the compression of the refrigerant, and have decided to change the unit yourself, you will need to prepare to work with an open circuit and high voltage electrical components.
In this article we will analyze in detail all the stages of replacement, from selecting a new spare part to the final start-up of the system. Remember that violation of soldering technology or incorrect filling freon can nullify all efforts. It is important to understand the risks and strictly follow the instructions to ensure the safety and durability of the repair.
Fault diagnosis and compressor selection
The first step is to accurately determine the cause of the breakdown. If the refrigerator hums but does not cool, or the compressor starts for a couple of seconds and clicks when it turns off, these are signs of a piston group wedge. It is also worth checking the start relay, as replacing it is much cheaper. For accurate diagnostics, it is often required water hammer or piston group wedge. It is also worth checking the start relay, as replacing it is much cheaper. Accurate diagnosis often requires a pressure gauge stationto show the pressure in the system.
When choosing a new compressor, it is critical to focus on the model of your refrigerator. You can’t just buy the first unit of a similar size that comes along. It is necessary to take into account the refrigerant (R134a, R600a or R12), the cooling capacity in BTU or kcal/h, and the start type (RSIR, RSCR). An error in the choice will lead to incorrect operation of the system or repeated breakdown.
⚠️ Attention: The use of a compressor running on R134a freon in a system designed for R600a is strictly prohibited due to differences in the properties of oils and operating pressures.
Modern inverter models require special caution. Replacement inverter compressor often involves reflashing the control board or completely replacing it, since old boards may not interact correctly with the new engine. In such cases, it is better to refer to the official documentation of the manufacturer.
How to find out the type of refrigerant?
On the back wall of the refrigerator, usually next to the compressor or on the inner wall of the chamber, there should be a sticker with technical information. Look for the "Refrigerant" or "Refrigerant" field. It will indicate the type of gas (for example, R600a) and its quantity in grams.
Required tools and materials
Replacing the motor in the refrigerator is not just a job with wrenches. You will need a specialized tool to work with copper tubing and evacuate the system. Without high-quality equipment, it is impossible to perform a hermetic joining of elements.
The main list of tools includes:
- 🔧 A set of open-end wrenches and screwdrivers for dismantling casings.
- 🔥 Gas burner (oxygen-propane or acetylene) for soldering of copper tubes.
- 🔩 Pipe cutter and rolling machine for preparing the ends of copper tubes.
- 🌡️ Manometric manifold (preferably with electronic scales for accurate filling).
- 💨 Vacuum pump to remove moisture and air from circuit.
You will also need consumables: solder (silver or copper-phosphorus), flux, nitrogen (for purging during soldering to avoid oxidation inside the tubes) and, of course, the refrigerant itself in the cylinder. Don't forget about personal protective equipment - gloves and goggles.
☑️ Readiness for repair
Preparing for dismantling the old unit
You can start work only after completely disconnecting the refrigerator from the power supply. Remove all food, defrost the chambers and remove the rear metal panel to gain access to the compressor compartment. Before starting any manipulations with the pipes, it is necessary to bleed off the remaining refrigerant.
Bleeding the gas should be carried out carefully, in a well-ventilated area or outdoors. Although modern refrigerants are less toxic than older freons, they displace oxygen and can be dangerous in confined spaces. After releasing the pressure, the tubes are cut with wire cutters.
Next, you need to remove the start relay and thermostat. They are usually mounted on or near the compressor housing. Before disconnecting the wires, take a photo or a connection diagram so that when assembling a new unit you do not mix up the contacts. An incorrect connection can burn the windings of the new motor.
Now you can start desoldering the copper tubes. Heat the joint with a torch until cherry red and carefully remove the solder. It is important not to overheat the tube itself, so as not to melt it. After disconnecting all lines, the compressor can be removed from the frame by unscrewing the mounting bolts or cutting off the shock absorbers.
Installation and soldering of a new compressor
Installation of a new unit begins with its fixation on the frame. If your model uses rubber shock absorbers, it is better to replace them with new ones, since the old ones harden over time and transmit vibration to the refrigerator body. The metal legs are screwed with bolts with groovers.
The most critical stage is soldering the connections. The condenser and evaporator pipes must be inserted into the compressor pipes with a small gap. Before soldering, be sure to flush the system with nitrogen to remove any possible dust and moisture. Soldering is done under nitrogen or by purging it through the system to prevent the formation of an oxide film inside the tubes, which could clog the capillary.
Use silver solder for a more reliable connection, especially if the system operates at high pressure. Apply flux minimally; its excess is also harmful to the system. After the seams have cooled, check them visually for holes and cracks.
⚠️ Attention: Never solder pipes that are under pressure or with refrigerant residues. This may result in an explosion and fire. Make sure that the system is completely depressurized.
After soldering, you need to connect the electrical part. Install a new start relay (the old one cannot be installed on a new compressor, even if it is working properly) and connect the wires according to the diagram made earlier. Check the reliability of the contacts.
Evacuation and charging with refrigerant
Simply replacing the engine is not enough - the system must be prepared for operation. There should be no air or moisture in it. To do this, a vacuum pump is connected to the service pipe (fitting). The evacuation process should last at least 20-30 minutes.
The purpose of evacuation is to reduce the pressure in the system to a level at which water boils at room temperature and evaporates. The remaining moisture in the system will freeze in the capillary tube and create an ice plug that blocks the circulation of freon. This is the most common mistake made by beginners.
| Refrigerant type | Vacuum pressure (mbar) | Evacuation time | Oil type |
|---|---|---|---|
| R134a | < 500 | 30-40 min | POE (synthetics) |
| R600a | < 300 | 40-50 min | Mineral |
| R12 (old) | < 500 | 30 min | Mineral |
| R404A | < 300 | 40-50 min | POE/PAG |
After evacuation, the valve is closed pump and the system is checked for leaks over a period of time. If the pressure does not increase, you can start refueling. Refueling is carried out strictly according to the weight indicated on the factory sticker of the refrigerator. The use of electronic scales is mandatory; refilling “by eye” or by pressure is unacceptable for household refrigerators.
Checking tightness and test run
After refilling, you must make sure there are no leaks. Places of soldering and connections are generously lubricated with soapy water and carefully monitored for the appearance of bubbles. Even a microscopic leak will eventually lead to loss of refrigerant and failure.
The first start-up is best done under the control of pressure gauges. The suction and discharge pressures must comply with the standards for the type of refrigerant and the ambient temperature. The compressor should operate smoothly, without strong vibration and extraneous knocks.
Pay attention to the temperature of the compressor housing. In the first hours of operation, it can heat up to 70-80 degrees, which is the norm for the break-in process. However, if only one part is heated or the temperature is critically high, this may indicate problems with the oil or overfilling of the system.
Typical errors and safety precautions
Repairing refrigeration equipment involves risks. One of the main mistakes is ignoring fire safety rules when working with a gas burner. Always have a fire extinguisher on hand and work away from flammable objects.
Another common mistake is insufficient vacuuming time. Many amateur craftsmen are in a hurry and turn on the compressor without completely removing the moisture. This leads to the formation of acid in the oil, which corrodes the motor windings from the inside. Such a compressor will burn out after a few months.
- 🚫 Do not leave the system open to air longer than necessary to minimize moisture ingress.
- 🚫 Do not use oxygen to purge or create pressure - this will cause an explosion with the oil.
- 🚫 Do not operate the compressor without a load connected or with the valves open, unless provided for in the instructions.
⚠️ Attention: Refrigerant R600a (isobutane) is a flammable gas. Work with it must be carried out with extreme caution, excluding sparks and open fire at the time of possible leakage.
Remember that improper disposal of old refrigerant is harmful to the environment. Try not to simply release it into the atmosphere, if it is possible to collect it in a container, although this is difficult to do in domestic conditions.
Is it possible to replace the compressor with an analogue from another company?
Yes, it is possible if the main characteristics match: power, type of refrigerant, overall dimensions and type of start. However, it is better to select original spare parts or proven analogues (for example, Aspera, Danfoss, Secop), since they are guaranteed to fit the seats.
How much does it cost to replace a compressor in a service?
The cost consists of the price of the compressor itself and the work of the technician. On average, replacement costs between 50% and 80% of the cost of a new refrigerator. Replacing it yourself saves money on work, but requires costs for tools.
Is it necessary to change the filter drier when replacing the compressor?
Absolutely. The filter drier is a disposable element. When the system is opened, it becomes saturated with moisture and ceases to perform its function. Installing an old filter is guaranteed to lead to clogging of the capillary tube.
Why does the compressor get very hot after replacement?
The reasons may be an excess or lack of freon, a malfunction of the condenser (poor heat transfer), or problems with the oil. It is also possible that the new compressor has a different efficiency and thermal load.