A compressor breakdown is one of the most serious and costly problems that a refrigeration equipment owner can face. Motor-compressor It is the heart of the system, ensuring the circulation of refrigerant, and its failure leads to a complete stop of refrigeration. Many users immediately call a technician, but experienced home craftsmen often decide to carry out the replacement themselves in order to save a significant amount.
Before you begin dismantling the old unit, you must clearly understand the risks and technical complexity of the process. Replacement compressor requires not only metalworking skills, but also a specific tool for working with the refrigeration circuit. Errors at the preparation or soldering stage can lead to failure of the new part or even fire.
In this article we will analyze the entire process from diagnosis to the first start. You will learn how to choose the right analogue, prepare the workplace and seal the system without a professional vacuum pump, using available methods. Remember that safety comes first, especially when it comes to high voltage flammable gases.
Diagnosing a motor-compressor malfunction
The first step should always be an accurate diagnosis. The absence of cold does not always mean the death of the engine; Sometimes the problem lies in the thermostat or start relay. If the refrigerator hums, but does not start, or starts for a couple of seconds and clicks, most likely it is the motor itself that is faulty. the starter or the engine itself.
The check begins with a visual inspection and listening. If the motor is hot but silent, the thermal protection relay may have tripped. Let the equipment cool for 30-40 minutes. If, after cooling, when turning on, a hum is heard, turning into a click, and the engine housing begins to heat up - these are signs of interturn short circuit or a piston group wedge.
⚠️ Attention: If you smell burning or see melted wiring in the area motor, it is prohibited to carry out further diagnostics without completely disconnecting from the network!
To more accurately determine the condition of the windings, use a multimeter. It is necessary to measure the resistance between the contacts. Normal readings for different windings usually vary, but no resistance (open) or zero resistance (short circuit) indicates the need for replacement.
Selecting a new compressor and preparing tools
The critically important stage is finding the right analogue. You can’t just buy the first motor of similar power that comes along. You need to pay attention to the type of refrigerant (R134a, R600a), cooling capacity (in W or kcal/h) and overall dimensions of the seats. Using unsuitable freon in a system designed for another can lead to destruction oil and jamming of the mechanism.
To carry out the work, you will need a specific set of tools. In addition to standard screwdrivers and pliers, a pipe cutter, flaring tool, and a torch are (required). If you do not have experience in soldering copper tubes, it is better to practice on scraps, since the quality of the seam directly affects the tightness.
You will also need a refill kit: a cylinder with freon, a pressure gauge station and, preferably, a vacuum pump. Although there are charging methods without vacuuming (blowing with freon), they are considered less professional and can shorten the service life of the unit.
| Parameter | Importance | Where to find | Error risks |
|---|---|---|---|
| Type refrigerant | Critical | Plate on the motor | Explosion, oil destruction |
| Power (W) | High | Model marking | Undercooling or overload |
| Landing feet | Average | Visual measurement | Vibration, impossibility of installation |
| Tube diameter | High | Calipers | Problems with soldering and joining |
Dismantling the old unit
The process begins with complete disconnecting the refrigerator from the power supply. Then you need to move the equipment aside, providing access to the rear wall. Remove the protective casing, if any, and gain access to the suction and discharge pipes. Before cutting the pipes, it is necessary to bleed off the remaining freon. This is done by slightly filing the tube or piercing the filter drier. The gas must come out completely, since its presence in the pipes will make soldering difficult and create pressure. After bleeding, you can cut the tubes with wire cutters, moving 10-15 cm away from the motor. injection and suction tubes.
Before cutting pipes, it is necessary to bleed off the remaining freon. This is done by slightly filing the tube or piercing the filter drier. The gas must come out completely, since its presence in the pipes will make soldering difficult and create pressure. After bleeding, you can cut the tubes with wire cutters, moving 10-15 cm away from the motor.
Disconnect the electrical wires from the terminals of the compressor and start relay. They are often secured with plastic clamps or latches. Carefully remove the rubber damper bushings that hold the motor and remove the old unit from the housing.
☑️ Checklist before dismantling
Technology of soldering and installing a new one motor
Installation of a new compressor is carried out in the reverse order of removal. First of all, secure the motor to the shock absorbers. Then you need to replace the filter drier - this is a mandatory rule for any opening of the circuit. The old filter is saturated with moisture and will not be able to efficiently clean freon.
The soldering process requires caution. Copper tubes are cleaned to a shine and solder is applied to them. The flame of the burner heats the joint, trying not to overheat the tube itself so that it does not burn out. Solder should melt from the heat of the pipe, and not from direct contact with fire.
⚠️ Attention: When soldering, always keep a wet rag on hand to instantly cool adjacent plastic elements or wiring if they begin to heat up from heat transfer.
Pay special attention sealing the process pipe, through which refueling will subsequently take place. It must be plugged reliably, since this is where microcracks often occur during vibration.
Nuances of working with freon R600a
Isobutane (R600a) is an explosive gas. Work with it should be carried out in a well-ventilated area, away from open flames and sparking tools. A gas concentration in the air of more than 1.3% creates an explosive mixture.
Evacuating and filling the system
After assembling the circuit and checking the tightness (you can apply a little nitrogen or freon under pressure and wash the joints), the system must be evacuated. This removes air and, most importantly, moisture. Moisture in the system freezes in the capillary, forming an ice plug that blocks circulation.
Connect the vacuum pump to the process connection and turn it on. The process should last at least 30-40 minutes. If there is no pump, some craftsmen use the purge method: open the freon valve for a few seconds, let the gas displace the air, then seal it. However, this method is less effective.
Refilling is carried out strictly according to the weight indicated on the label inside the refrigerator compartment, or according to the pressure in the system if an analogue refrigerant is used. Excess freon will lead to increased pressure and load on the motor, and too little will lead to poor cooling.
First start-up and leak check
After filling, seal the process pipe. Plug in the refrigerator. For the first 15-20 minutes, do not close the doors and watch the work. The motor should run smoothly, without strong vibration and extraneous sounds.
Check the heating of the condenser (grid at the back). It should heat evenly over the entire area. If only part is heated, there may be an air lock in the system or low freon. Also check the evaporator inside the chamber - it should be covered with frost evenly.
Be sure to carry out a final check of the joints with a soap solution. Even a microscopic leak will eventually lead to loss of refrigerant and subsequent repairs. If bubbles do not appear and the temperature drops to the specified values, the replacement can be considered successful.
Frequently asked questions (FAQ)
Is it possible to replace a compressor without a vacuum pump?
It is technically possible to use the freon blowing method, displacing air with gas pressure. However, this is less reliable, since it does not remove moisture from the walls of the tubes, which can lead to the formation of acid and corrosion inside the system after a few months.
Why does the new motor get hotter than the old one?
Modern compressors often have higher efficiency, but also operate at higher housing temperatures. If the temperature does not exceed 80-90 degrees and the refrigerator freezes, this may be normal. However, it is worth checking the current consumption with an ammeter.
How much does it cost to replace a compressor compared to buying a new refrigerator?
The cost of work and a new motor is usually 30-50% of the price of a new budget refrigerator. If the equipment is more than 10-12 years old, it is often more economically feasible to buy a new device, since problems with freon leaks due to corrosion may begin.
Do you need to change the starting relay when replacing the motor?
Yes, this is highly recommended. An old relay could cause the previous motor to fail (for example, the contacts are stuck), and installing it on a new unit can lead to a quick breakdown.