Failure of a compressor is perhaps the most serious blow to the budget of the owner of refrigeration equipment. It is this unit that is the “heart” of the system, ensuring the circulation of the refrigerant, and its failure often leads to a complete stop of the cooling process. Many users immediately call a technician, fearing difficulties associated with the tightness of the circuit and working with electricity, but replacing it yourself can save a significant amount of money.
Before you begin dismantling the old unit, you must clearly understand the risks and the scope of the work required. Replacement compressor requires not only mechanical skills, but also special equipment for soldering copper tubes and evacuating the system. If you are not confident in your abilities or you do not have access to the necessary tools, it is better to stop at the diagnostic stage or invite a professional, since poor-quality soldering will lead to freon leakage and repeated repairs.
However, for those who have experience working with power tools and are ready to follow safety precautions, this task is completely solvable. In this article, we will analyze in detail the process of selecting analogues, soldering technology and the features of starting the engine so that you can do the work with the highest quality and safety for yourself and the equipment.
Fault diagnosis and signs of failure
The first step should always be an accurate diagnosis, since the absence of cold does not always mean the death of the motor. Often the problem lies in the start relay, thermostat or a banal freon leak, which can be fixed without replacing an expensive component. If the compressor hums but does not start, or it operates continuously without reaching the set temperature, this is a reason for a deeper analysis of the condition of the electric motor. Pay attention to the nature of the sound of the operating unit. A healthy motor produces a smooth, quiet hum, while a faulty one may make clanging, knocking or sharp clicking noises. Also an important indicator is the temperature of the housing: if it is too hot or, conversely, remains cold when the relay is operating, this indicates internal problems in the windings or mechanical jamming of the piston group. electric motor.
Pay attention to the nature of the sound of the operating unit. A healthy motor produces a smooth, quiet hum, while a faulty one may make clanging, knocking or sharp clicking noises. Also an important indicator is the temperature of the housing: if it is too hot or, conversely, remains cold when the relay is operating, this indicates internal problems in the windings or mechanical jamming of the piston group.
- 🔊 The compressor makes a loud metallic knock or clanging sound when trying to start.
- 🔥 The motor housing overheats (above 90°C) or remains absolutely cold when the power is turned on.
- ⚡ The circuit breaker in the electrical panel is triggered or the plugs are knocked out when the refrigerator is turned on.
- ❄️ The refrigerator compartment does not cool, although the fan and light are working properly.
For final confirmation of the diagnosis, you need to "ring" windings with a multimeter. The resistance between the contacts must be within certain limits, usually from 10 to 30 Ohms for the starting winding and slightly less for the working winding. If the device shows infinity (break) or zero (short circuit), then replacement of the compressor is really necessary, since it is impossible to restore a burnt winding at home.
Necessary tools and preparation of the workplace
The success of the operation directly depends on the quality of training and the availability of specialized equipment. Unlike replacing filters or seals, working with the refrigeration circuit requires tightness, which can only be ensured by high-quality soldering. You will need not only a standard locksmith kit, but also tools for working with non-ferrous metals and gas.
A critical element is the presence of an oxygen-propane torch or a high-quality soldering iron for hard solder. Regular tin solder will not withstand system pressure and temperature changes, so use only silver solder or special alloys for copper tubes. It is also necessary to have nitrogen for purging, although in extreme cases craftsmen use the refrigerant itself, but this is a less professional approach.
⚠️ Attention: Carry out soldering work only in a well-ventilated area. Open flames and freon vapors can form toxic compounds that are hazardous to breathing.
In addition to soldering equipment, you will need a vacuum pump and a pressure gauge station. Without evacuation of the system, moisture and air will remain in the tubes, which will lead to the formation of ice plugs and rapid corrosion from the inside. Also, do not forget to prepare tools for cutting and bending copper pipes to avoid creases that will block the flow of refrigerant.
Selecting and purchasing a suitable compressor
Selecting a new unit is not just buying the first model you come across with similar dimensions. Compressors vary in power, type of refrigerant, overall dimensions and type of starting equipment. An error in selection may lead to the fact that the new motor will work with overload or will not be able to create the necessary pressure in the system.
First of all, pay attention to the markings of the old device. You need to find a model that runs on the same type of freon (R134a, R600a, R12) as the original. Using a compressor designed for one type of refrigerant with another oil or gas will lead to rapid failure and destruction of internal lubrication.
| Parameter | Description | Importance |
|---|---|---|
| Refrigerant type | Must strictly correspond to the system (R134a or R600a) | Critical |
| Power (LBP/MBP/HBP) | Low, medium or high boiling pressure | High |
| Overall dimensions | Length, width, height of seats | Average |
| Tube diameter | Internal and external diameter of suction and discharge | High |
It is also worth considering the manufacturer. Original spare parts from Secop (Danfoss), Embraco or LG usually last longer and are quieter than cheap Chinese counterparts. However, if the budget is limited, you can consider certified replacements, but be sure to check for guarantees and certificates of conformity.
Is it possible to install a more powerful compressor?
Theoretically, it is possible, but this will lead to an imbalance in the thermal balance. The evaporator will not have time to absorb the cold, which will cause freezing and improper operation of the thermostat. It is better to install a strictly analogue in power.
Step-by-step instructions: dismantling and preparation
We start by completely disconnecting the refrigerator from the power supply. This is a basic safety rule that cannot be ignored. After this, move the unit away from the wall, allowing access to the rear from all sides. Remove the protective back panel to gain access to the compressor area.
The next step is to remove the old refrigerant. If the system is not damaged and freon is still inside, you must carefully pierce the filling tube or loosen the connection by venting the gas in a well-ventilated area. Keep open flames away from escaping gas. After releasing the pressure, you can begin to disconnect the electrical contacts and the start relay.
Now is the time to use the burner. Gently heat the soldering joints of the copper tubes on the suction and discharge. When the solder has melted, remove the tubes. Be careful: copper heats up quickly and can cause burns. The old compressor is usually mounted on four rubber shock absorbers or metal studs - unscrew them and remove the unit.
- 🔌 Disconnect the block with wires and remove the starting relay with the capacitor.
- 🔥 Heat the entry points of the tubes into the compressor housing with a torch until melting solder.
- 🔩 Unscrew the mounting bolts and remove the motor from the frame, being careful.
- 🧹 Clean the surface of the condenser from dust and dirt before installing a new unit.
It is important to maintain the integrity of the filter drier if you plan to reuse it, although professionals recommend changing it in conjunction with a compressor. The filter accumulates moisture and oil breakdown products, and its reuse can negate all repair efforts.
Soldering technology and installation of a new unit
Installation of a new compressor begins with preparing the pipes. If the diameters of the tubes of the new motor do not match the old ones, use adapters. Carefully insert the tubes into the corresponding holes of the compressor: suction (thicker) and discharge (thinner). The gap should be minimal, but without interference.
The soldering process requires skill. Heat the connection evenly by moving the flame around the tube to warm both the tube and the compressor fitting. When the metal reaches the desired temperature, bring a rod of solder to the joint - it should melt and flow into the gap under the influence of capillary effects. Do not pour solder directly onto the flame, it should melt from the hot metal.
⚠️ Attention: When soldering, keep the compressor in a vertical position or with a slight tilt so that oil does not leak out of the internal cavities through the open tubes.
After soldering all connections, you must check the system for tightness. To do this, connect a pressure gauge station, create excess pressure with nitrogen (about 10-15 atmospheres) and leave for several hours. If the pressure gauge needle does not fall, then the system is sealed and you can proceed to vacuuming.
☑️ Check before soldering
Evacuation and charging with refrigerant
Evacuation is the process of removing air and moisture from the system. Moisture in the system freezes in the capillary tube, forming an ice plug that blocks the circulation of freon. Connect the vacuum pump to the service connection and turn it on. The process should last at least 30-40 minutes until the pressure drops to a deep vacuum.
After reaching a vacuum, close the valve at the station and turn off the pump. Wait 15-20 minutes and check the pressure gauge. If the arrow remains in place, the system is sealed. If the pressure begins to increase, it means that somewhere there is a micro-leak that needs to be found and eliminated by re-soldering.
Refrigerant charging is carried out strictly according to the weight indicated on the factory sticker inside the refrigeration chamber. The use of a cylinder with scales or a volumetric flask is mandatory, since it is impossible to fill the system correctly “by eye”. Excess or lack of freon will lead to incorrect operation of the refrigerator.
First start-up and operation control
After refueling, you can make the first start. Plug in the refrigerator and listen to the motor running. It should start with a quiet beep and no clunking or vibration. After 10-15 minutes of operation, check the temperature of the discharge tube - it should be hot, and the suction tube should be cold, possibly with the appearance of condensation or light frost.
Monitor the operation of the refrigerator during the first 24 hours. Pay attention to the on and off cycle: the motor should not run continuously. If the refrigerator reached the temperature and turned off, and then turned on on its own after some time, the repair was successful.
Do not forget to put back the protective cover and move the refrigerator to the wall, observing clearances for ventilation. A properly installed and maintained compressor will last for many years, ensuring the safety of your products.
How long does it take to replace a compressor with your own hands?
For an experienced technician with all the tools, the process takes from 2 to 4 hours, including time for vacuuming and checking for leaks. A beginner may need up to 6-8 hours, especially if there are difficulties with soldering or selecting adapters.
Does it need to change the filter drier when replacing the compressor?
Yes, definitely. The filter drier is a disposable element. After opening the circuit, it is saturated with moisture from the air, and its reuse will lead to the formation of an ice plug in the system and the breakdown of the new compressor.
Is it possible to refill a refrigerator without a scale?
It is strictly not recommended. The amount of refrigerant must be accurate (to the nearest gram). A lack of freon will lead to overheating, and an excess will lead to increased pressure and load on the compressor, which will shorten its life.
Why does the compressor hum, but does not start after replacement?
Most often the problem is in the starting relay or capacitor. It is also possible that the starting winding may break or the piston group of the new unit may jam. Check the voltage at the contacts and the serviceability of the starting equipment.