The situation when a home refrigerator stops cooling or starts make extraneous sounds, often leaves the owner with a choice: call a technician or try to solve the problem on his own. Compressor is the heart of the cooling system, and it is its malfunction that most often causes a breakdown. Many enthusiasts are wondering how to disassemble a refrigerator motor in order to carry out diagnostics, change the oil, or try to revive a jammed unit. This is a complex technical task that requires not only skills, but also an understanding of the physical processes occurring inside the sealed casing.
Before taking up the tools, you must clearly understand that a standard household compressor is a device not intended for repair at home. Factory sealing of the case involves replacing it as an assembly, rather than opening it. However, knowledge of the internal structure is necessary for proper diagnosis, replacement of the start relay or disposal. In this article, we will look in detail at the stages of dismantling, methods for opening the casing and the nuances of working with internal components, so that you can make an informed decision about the advisability of such actions.
It is important to understand that inside the system may be Freon under pressure, as well as special compressor oil, which should not enter the cooling system during reassembly. Sealed casing hides complex mechanics, where the gaps between parts are measured in microns. Any mistake during disassembly can lead to the fact that the unit will never start or will work extremely inefficiently, creating excess pressure.
Compressor design and principle of operation
In order to properly disassemble, you need imagine what is inside a steel barrel. A compressor is an electromechanical unit where electrical energy is converted into mechanical movement of a piston. The basis is electric motor, the shaft of which drives the crank mechanism. This entire structure is suspended on springs inside a sealed housing, which is necessary to minimize vibration and noise during operation.
The working process begins with applying voltage to the stator windings. The rotor begins to rotate, transmitting torque to the crankshaft. The piston, moving up and down, sucks gaseous refrigerant through the suction tube and, under high pressure, pushes it into the discharge tube. Valve system strictly controls the direction of movement of the freon, preventing it from returning back. Malfunction of any of these elements requires accurate diagnosis.
Lubrication of rubbing parts is carried out by splashing oil, which is located in the lower part of the housing. The compressor shaft often has a special recess or channel, which, when rotated, captures oil and supplies it to the bearings and cylinder. Lack of oil or its contamination with wear products is one of the main reasons for motor jamming. That is why, during deep disassembly, the condition of the oil bath is given paramount attention.
⚠️ Attention: Residual pressure may be maintained inside the housing. Before starting any work on sawing the housing, make sure that all tubes are open and the pressure inside is equal to atmospheric pressure to avoid a sudden release of oil or refrigerant vapor.
Disassembling the motor is often required not to repair the compressor itself, but to replace the oil, which oxidizes over time and loses its properties, or to replace the valve group. However, it is worth remembering that after opening the case, the factory seal is broken forever. Re-sealing by welding or soldering at home is practically impossible without special equipment, so most often such units are used for conversion into compressors for airbrushing or inflating tires.
Necessary tools and safety measures
Working with electrical equipment and metal structures requires strict adherence to safety precautions. The first step is to completely turn off the power to the refrigerator by removing the plug from the socket. For disassembly, you will need a set of tools that will allow you to safely dismantle the unit and open its housing. Do not neglect personal protective equipment, as the process can be traumatic.
The main list of necessary equipment includes:
- 🔧 A set of screwdrivers (phillips and flat) for removing terminals and relays.
- 🪚 Angle grinder (grinder) with a thin metal disc for cutting the body.
- 🛡️ Safety glasses and gloves to protect from metal shavings and sharp edges.
- 🧪 A container for draining old oil and a funnel.
- 🔨 Hammer and chisel (as an auxiliary tool for opening).
Particular attention should be paid to the electrical part. Before touching the insides, make sure that the capacitors (if any in the circuit) are discharged Start relay and the thermal relay may have a residual charge or be hot from recent operation. It is also worth preparing the workplace: it should be well lit and ventilated, since when working with an angle grinder there will be a lot of dust, and oil vapors have a specific smell.
If you plan to use the compressor in the future to create pressure (like an air pump), make sure that the insides are completely cleaned of wear products and old oil. For washing, you can use special solvents or Galosh gasoline, but this must be done away from sources of fire. Rubber seals the inside may not withstand aggressive chemicals, so it is better to immediately replace them with new ones during assembly.
☑️ Preparation for disassembly
Removing the compressor from the refrigerator
The process of removing the motor from the refrigerator is the first stage, which must be approached carefully so as not to damage copper tubes if you plan to use them in the future. The compressor is usually located at the lower rear of the unit, in a niche. Access to it may be limited by a metal cover or a plastic casing, which must be removed by unscrewing the mounting bolts.
Before disconnecting the pipes, the refrigerant must be vented. In a factory setting, this is done by puncturing the system, but at home, they often simply cut through the copper tubes next to the compressor. Be prepared for gas hissing. After releasing the pressure, the tubes are cut with wire cutters or sawed off with a hacksaw, leaving “tails” of sufficient length. Soldering This is not required here yet, the main thing is to free the unit.
Next, the electrical part is disconnected. On the compressor body there is a plastic box in which the contacts are hidden. After removing the cover, you will see wires running from the refrigerator to the start and thermal relay. They must be disconnected by first photographing the connection diagram or marking the wires with a marker, so that if the assembly is successful, you will know where to connect what.
The compressor itself is attached to the frame of the refrigerator with four metal legs. They can be bolted or welded. Most often, bolted connections are used, which stick over time. To unscrew them, you may need a penetrating lubricant, for example WD-40. After unscrewing all the fasteners, the unit can be removed from the niche.
| Element | Function | Mounting type |
|---|---|---|
| Start relay | Engine start | Pin connection |
| Thermal relay | Overheat protection | Put on the body |
| Vibration supports | Quenching noise | Rubber bushings |
| Copper tubes | Freon circulation | Soldering/Rolling |
After removing the motor, it is recommended to clean its surface from dust and dirt, accumulated over years of work. This will not only improve aesthetics, but will also allow you to better see the places of cuts and fasteners during further disassembly. Heat exchanger (if it remains on the tubes) can also be washed with water, but the compressor itself should not be wet.
Opening the sealed housing
The most important and dangerous stage is breaking the tightness of the steel casing. The factory welding is done very well, so simply “unscrewing” the lid will not work. There are two main methods of opening: mechanical (cutting) and thermal (burning), but at home it is safer and more reliable to use an angle grinder.
First you need to determine the junction line of the upper and lower parts of the casing. It usually runs down the middle of the barrel and is often covered with a layer of paint or rust. Clean this perimeter with a metal brush. Mark the cutting line with a marker, stepping back from the joint about 3-5 millimeters towards the top cover, so as not to damage the internal springs and windings when sawing.
Turn on the grinder and begin to carefully move the disc along the marked line. Do not put too much pressure on the tool, let the disc work on its own. It is important not to cut through the body right away, but to make a shallow cut along the entire perimeter, gradually increasing the depth. Sparking It will be strong, so hold the tool firmly and watch the position of your hands.
What to do if there is no grinder?
If you don’t have an angle grinder, you can use a hacksaw, but the process will take much longer. There is also a method of knocking out the lock, but this requires a lot of experience and can deform the housing, making it unsuitable for reassembly.
When the circle has passed the entire perimeter and the cutting depth is sufficient, the upper part of the casing should be removed. If it holds, you can gently tap the perimeter with a rubber mallet. Do not use a metal hammer directly on the housing to avoid damaging the internal stator windings. After removing the cover, you will see the “inner world” of the compressor.
⚠️ Attention: When cutting the housing, small metal shavings are formed. It is strictly forbidden to allow it to get inside the motor onto the windings or into the cylinder, as this will lead to a short circuit or scuffing of the piston. It is recommended to blow out the cut site with compressed air during operation.
Diagnostics and replacement of internal components
After opening, access to the main components opens: stator, rotor, crankshaft and valve group. First of all, assess the condition of the oil. If it is black, thick, or has a burning smell, it needs to be completely drained and replaced. To do this, the compressor is tilted, draining the waste into a prepared container. Washing the insides with a special compound will help remove sludge.
The valve group is often the cause of failure. It is located on top of the cylinder and covered with a plate. After unscrewing the mounting screws, you can remove the plate and inspect the reed valves. They should fit snugly on the saddles. If you notice cracks, deformation or carbon deposits, the valves need to be replaced or carefully straightened (if the thickness of the metal allows). Valve tightness is a key factor in compression.
It is also worth checking the condition of the connecting rod and piston. Shake the shaft with your hand: there should be no play, but also no jamming. If the shaft is difficult to turn, the bearings may be jammed or carbon deposits have formed in the cylinder. In such cases, soaking the moving parts in solvent or kerosene for several hours can help. Anti-friction coatings may be damaged, so high-quality lubrication will be required after cleaning.
The electric motor deserves special attention. Visually inspect the windings for blackening or melting. Test them with a multimeter: the resistance between the common point and the starting/working winding should be within normal limits (usually from 10 to 30 Ohms). If the device shows a break or short circuit to the housing, the engine cannot be repaired.
Assembly and sealing unit
Assembling a motor after disassembling is a process that requires maximum care. The main difficulty is that the standard method of factory sealing (argon welding) is not available at home. Therefore, to restore functionality as a refrigeration unit, you have to resort to tricks, although this does not provide guarantees of durability.
If you still decide to try to put the case back together, the edges of the upper and lower parts must be thoroughly cleaned from rust and paint to bare metal. A seal is placed between the halves. As a gasket, you can use a heat-resistant sealant applied in a thick layer, or cut a gasket from paronite. The halves are combined and tightly tightened with clamps around the perimeter.
For fixation, you can use the method of soldering with tin along the seam, if the body material allows, or leave it on the sealant, understanding that such a seam may not withstand the pressure. However, a more reasonable solution for a self-assembled unit is to use it as a compressor for airbrush or inflating wheels, where the requirements for tightness and type of gas are lower than in the refrigeration circuit.
After assembly, it is necessary to fill in new compressor oil. Its volume is usually 250-300 ml, but the exact amount depends on the model. You need to pour oil through the technological holes until it stops being absorbed. Then the performance is checked: a short start will show whether there are any vibrations, knocking and whether the compression is sufficient.
It is important to note that if the goal was to repair the refrigerator for further use for its intended purpose, then after assembly it will be necessary to evacuate the system and fill it with freon. This requires a vacuum pump, a pressure gauge station and a refrigerant cylinder. Without this step, the refrigerator will not work.
Frequent errors during disassembly and operation
Beginners often make mistakes that nullify all efforts. One of the most common is neglect of cleanliness. Even the smallest speck of dust or shavings getting into the cylinder leads to scratches on the cylinder bore and piston, which instantly kills compression. You need to work in a clean room, using clean tools.
Another mistake is incorrect selection of oil. The use of unsuitable lubricant (for example, spindle or transformer oil instead of compressor oil) leads to rapid wear of friction pairs. Oil viscosity must meet the requirements of the compressor manufacturer. Also, you cannot mix oils of different types, as they can enter into a chemical reaction and form a precipitate.
Electrical safety is often forgotten when checking the assembled unit. You can connect the motor directly to the network, without a starting relay, only for a short-term check of shaft rotation. Prolonged operation without the correct connection diagram will lead to burnout of the windings. The relay is selected strictly for the power and starting current of a particular engine.
⚠️ Attention: If after assembly and startup the compressor heats up more than usual or makes a metallic clanging sound, immediately turn off the power. Operation of a faulty unit can lead to a fire or destruction of the housing under pressure.
And finally, many try to save on gaskets by using old sealant or laying paper. This is unacceptable. The seal must withstand pressure up to 15-20 atmospheres and temperatures up to 100 degrees Celsius. Only high-quality materials will ensure the tightness of the system.
Is it possible to repair a compressor if it is jammed?
If the jamming is caused by a lack of oil or light carbon deposits, sometimes “rocking” helps. To do this, apply increased voltage to the windings (for a short time) or try to rotate the shaft manually through the valve group after removing the cover. However, if there is mechanical damage (scuffing, broken connecting rod), repair is impossible.
What kind of oil should be poured into the compressor after disassembly?
It is necessary to use special synthetic oils, such as polyol ether (POE) or alkyl benzene (AB). The marking often depends on the type of freon the compressor worked with. R134a and R600a require different types of oils. A universal solution for converted compressors is considered to be oil for refrigeration machines of the Bitzer BSE32 type.
Why does the compressor hum after assembly, but does not pump?
Most likely, the tightness of the valve group is broken or the valves are assembled incorrectly. The reason may also be a lack of compression due to wear of the piston group or incorrect assembly of the housing, which causes poor clearances. Check the tightness of the reed valves.
Is it safe to open the compressor yourself?
The process carries risks: high pressure (if not vented), electric shock, sharp metal shavings and chemicals. If you follow safety precautions and have experience working with the tool, the risk is minimal. However, for inexperienced users, it is better to turn to professionals or replace the unit with a new one.
What to do with freon during disassembly?
Freon must be vented in a well-ventilated area or outside. On an industrial scale, it is collected in cylinders for disposal. In everyday life, they simply let the gas escape through a broken tube. Remember that freon is heavier than air and can displace oxygen, so do not lean over the gas outlet.