Diagnostics of refrigeration equipment malfunctions often comes down to the need to check or replace the main unit - the motor-compressor. If the unit hums, but does not cool, or is completely silent when the wiring is in good condition, the question arises of dismantling this expensive unit. Self-replacement compressor requires not only technical skill, but also strict adherence to safety precautions, since the work involves high voltage and refrigerant.
The process of removing the unit varies depending on the manufacturer and model of your refrigerator, whether massive Liebherr or compact Indesit. However, the basic design principle remains similar for most models released over the past decades. It is important to understand that simply “unscrewing” it will not work - you will need to cut the copper tubes and disconnect the electrical contacts.
Before taking active steps, you need to make sure that the problem lies precisely in the mechanical or electrical part of the motor, and not in the start relay or thermostat. Often users change a working compressor, although it was enough to replace the start-up relay. If you are confident in the diagnosis, preparation for dismantling will be the first and most important stage of successful repair.
⚠️ Attention: Before starting any work, be sure to unplug the refrigerator from the electrical outlet and remove the plug from the outlet. Working with electrical wiring and sealed systems under pressure without turning off the power is deadly.
Necessary tools and workplace preparation
For high-quality dismantling, you will need a specific set of tools, which are rarely found in a standard home first aid kit. The main tool will be a pipe cutter designed specifically for copper, since using a hacksaw for metal can lead to chips getting inside the system, which will fatally affect the operation of capillary tube and the new compressor.
You will also need pliers, wrenches (usually 8, 10 and 12 mm), flat and Phillips head screwdrivers. To seal the system after installing a new unit, you will need a gas torch and solder, or, in extreme cases, special crimp couplings, although professionals recommend only soldering. Don't forget to prepare a container to catch any residual oil that may leak from the old unit.
Organizing the space around the refrigerator is critical. You need to provide access to the back wall from all sides. Move the equipment at least a meter away from the wall so that you can freely walk around the unit. It is better to cover the floor with rags or polyethylene, since the oil from the compressor can be hot and have a specific smell that is difficult to remove from the floor covering.
- 🔧 Pipe cutter for copper pipes (diameter 1/4 and 3/8 inches).
- 🔥 Gas burner with a cylinder (for subsequent soldering).
- 🔌 Multimeter for checking the integrity of the windings.
- 🧤 Protective gloves and glasses (required when cutting metal).
⚠️ Attention: Never use ordinary wire cutters or metal scissors to cut through refrigerator tubes. Deformation of the edge of the pipe will make high-quality soldering impossible in the future, and metal dust will damage the filter drier.
Access to the engine compartment and visual inspection
After the refrigerator is turned off and moved away, you need to gain access to the lower rear part of the case. In most modern models, such as Samsung or LG, the compressor is closed with a metal or plastic casing. It is secured with latches or bolts that must be carefully removed. In old Soviet models, access may be open, but closed with thermal insulation material.
Removing the cover, you will see the compressor itself, most often black, mounted on the frame. It is connected to two copper tubes (discharge and suction) and an electrical cable that goes into a plastic box with a start relay. Before touching anything, conduct a visual inspection for obvious damage to the wire insulation or traces of oil leakage in the places where the tubes are rolled.
Pay attention to the condition vibration isolators — of the rubber bushings on which the motor is installed. If they have dried out or burst, this may be the cause of increased noise, which users often confuse with a breakdown of the compressor itself. In some cases, replacing these cheap rubber bands eliminates the problem without complex repairs.
If visually everything looks intact, you can move on to more detailed manipulations. It is important to remember or photograph the wiring diagram, since the insulation colors may not correspond to the standard, especially if the refrigerator has been previously repaired. An error when connecting phase and zero to the starting winding can instantly burn out a new or working motor.
Disconnecting the electrical part and checking the windings
The first step in the dismantling process is to disconnect the electrics. On the compressor housing there is a terminal box covered with a plastic cap. Carefully remove the retainer or unscrew the screw holding the cover in place. Underneath it you will see the start relay and thermal relay, placed on the three contact pins of the compressor.
Remove the entire relay or disconnect the wires going to it, having previously marked them with a marker. Now you have access to the winding contacts. Using a multimeter in resistance mode, check the integrity of the windings. The resistance between the common point and the starting winding, as well as between the common point and the working winding, must be within normal limits (usually from 10 to 30 Ohms).
Normal multimeter readings:Working winding: 15-25 Ohms
Starting winding: 30-50 Ohm
Case: Infinity (∞)
If the device shows one or infinity on the windings, it means a break has occurred and the compressor must be replaced. If the resistance is close to zero, there is a short circuit. Also, be sure to check that there is no breakdown on the case: press one probe of the multimeter to the stripped metal of the case, and touch the contacts with the other. The device should not respond.
- 📸 Take a photo of the wire connection diagram before disconnecting.
- 🔌 Check the integrity of the wires for melted insulation.
- 🧪 Make sure that there is no moisture or oxides in the terminal box.
⚠️ Attention: If after checking it turns out that the windings are intact, but the motor does not start, the problem may be in the starting relay. Replacing the compressor in this case is not required and will be a waste of money.
Removing the compressor: cutting the tubes and removing the fasteners
When the electrical part is turned off and the diagnosis is confirmed, the most crucial moment comes - the physical release of the unit. The compressor is supported on the frame by four supports, which are bushings with rubber shock absorbers and metal washers. To remove, you need to press these washers down while lifting the motor housing.
Use a flathead screwdriver or a special puller to carefully bend the lock washers. Proceed with caution: if the rubber bushing breaks, the new compressor will vibrate and rattle. In some models Bosch or Siemens fastenings can be made in the form of bolts, which greatly simplifies the task.
The most important technical point is cutting copper pipelines. Using a pipe cutter, it is necessary to cut through the suction and discharge tubes at a distance of 10-15 cm from the compressor housing. It is strictly forbidden to cut through the tubes directly at the compressor housing itselfas this can damage the internal structure of the pipes, and it will not be possible to seal them hermetically again.
☑️ Algorithm for removing the compressor
After disconnecting the pipes, residual refrigerant and oil vapor may escape from the system under pressure. Be prepared for this and keep a rag handy. Try not to tilt the compressor too much so that oil does not flow out through the open evaporator tubes if the system has not yet been completely evacuated (although when removing the compressor itself, this is less critical than when refueling).
Types of fastenings and features of different manufacturers
The design of refrigeration units has its own characteristics depending on the brand. Understanding these nuances helps to avoid damage to fasteners. For example, refrigerators Atlant and Biryusa often use simple bolted connections that can be easily unscrewed with a key.
European brands, such as Electrolux or Zanussican use combined fasteners, where The compressor is suspended on springs inside the frame. It is important here not to lose the springs and install them correctly when installing a new unit. Incorrect installation results in the compressor hitting the metal walls of the housing during operation.
| Brand | Mounting type | Dismantling feature | Location |
|---|---|---|---|
| Atlant | Bolt (4 pcs.) | Requires a 10 mm wrench | Bottom, open |
| Samsung | Rubber bushings | You need to press the washers | Closed casing |
| Liebherr | Combined | Difficult access to tubes | In the rear niche |
| Indesit | Rubber pads | Often stick from rust | Bottom, open |
When working with rusty fasteners, which is often found on older models, use a penetrating lubricant (for example, WD-40). Give it time to work before making any effort. A sharp jerk can break the fastening eye on the frame of the refrigerator, the restoration of which will require welding work.
What to do if the fastening eye breaks?
If during dismantling you tore off the metal eye on the frame, do not despair. You can use metal clamps with a rubber gasket to secure the new compressor, or weld new fasteners. The main thing is to ensure reliable fixation so that vibration does not destroy the system.
Common mistakes when removing and disposing of the old unit
One of the most common mistakes of beginners is neglecting cleanliness when working with tubes. Dust, moisture or metal shavings that get inside the copper tube will inevitably lead to blockage capillary. This means that even a new expensive compressor will not cool, and the system will have to be opened again to purge with nitrogen.
Another mistake is storing the removed compressor in the wrong position. If you plan to use the old unit for some purpose (for example, as a compressor for an airbrush), remember that it can only be transported and stored in a vertical position, just as it was in the refrigerator. An inclination of more than 40 degrees can lead to oil leakage into the refrigerant circuit.
Disposing of an old compressor requires responsibility. It contains industrial oil that should not be poured down the drain or onto the ground. Take the unit to scrap metal collection points or specialized household appliance recycling centers. This is an environmentally friendly way to get rid of a used unit.
- 💧 Do not leave open system pipes without plugs (use electrical tape or special plugs).
- 🛢️ Do not drain the oil from the old compressor into the sink.
- 🔨 Do not hit the pipes with a hammer to tear them off - only cutting.
Preparation for installing a new compressor
After successful dismantling of the old unit, it is necessary to prepare a place for installing a new one. Clean the frame from dirt, oil and rust. Check the condition of the new fastening rubber bands - they should come with the new compressor. The use of old, “tired” rubber bands is unacceptable, since they will not be able to dampen vibration.
A new compressor also requires preparation. At the factory, it is injected with nitrogen at low pressure to prevent moisture from entering. The plugs on the pipes of the new unit must be removed immediately before soldering. If you remove them in advance, moist air will quickly saturate the insides of the motor, which will lead to the formation of ice plugs in the system.
Now that the old compressor has been removed and the new one has been prepared, you can begin soldering the pipes and vacuuming the system. This stage requires professional equipment: a vacuum pump and a pressure gauge station. Without creating a vacuum in the system, charging with refrigerant is impossible, and the refrigerator will not work.
Is it possible to remove a compressor without a pipe cutter?
Theoretically, you can use a hacksaw with a very fine tooth, but this is not recommended at all. The file will create a huge amount of metal shavings that will enter the system. It is almost impossible to clean it, and it is guaranteed to damage the new compressor or clog the capillary tube in the very first hours of operation.
How much does a standard compressor weigh?
The weight of a household compressor usually ranges from 10 to 20 kg, depending on the power and model. However, when dismantling, it is important to take into account not only the weight, but also the dimensions, as well as the presence of oil inside, which can spill out when tilted.
Is it necessary to bleed off the freon before removal?
When removing the compressor itself, the freon in the system will be released automatically when the tubes are cut. There is no need to specifically bleed it in advance through the Schrader valve (if there is one), unless you plan to store the refrigerant for reuse, which is not done in domestic conditions.
Why does a new compressor hum after installation?
A hum can be caused by several reasons: the tubes touching the housing or each other, a malfunction of the new compressor itself (defect), incorrect connection of the start relay or lack of vacuum in the system. Also, the cause may be incorrect installation of vibration isolators.
Is it possible to solder tubes without nitrogen?
Soldering copper tubes is possible without purging with nitrogen, but this reduces the quality of the connection. When copper is heated, an oxide film (slag) forms inside the pipe, which over time can come off and clog the filter drier. Professional repairs always involve purging with nitrogen when soldering.