The situation when the refrigerator stops freezing and the compressor is silent or makes strange sounds is familiar to many owners of household appliances. This often becomes a reason to call a craftsman, but for those who like to make things with their own hands, it can be an excellent chance to delve into the design of the equipment. Disassembly sealed assembly is a process that requires not only accuracy, but also an understanding of the risks associated with high pressure and electricity.
Before taking up the tools, you must clearly understand: the factory motor housing is tightly sealed. This is done so that freon and oil do not come into contact with air and moisture. Simply opening the case with an angle grinder or a hacksaw without subsequent professional welding makes the unit unsuitable for further normal operation in the cooling system. However, if your goal is to remake the device for a compressor workshop, airbrush, or simply diagnose internal mechanical damage, then this instruction will become your guide.
In this article we will take a detailed look at the process of dismantling, removing the cover and diagnosing the internals. We will not discuss methods for soldering copper tubes, since the focus is on the mechanical part of the electric motor. Be prepared for the fact that the process will require time and compliance with safety precautions.
Preparation of the workplace and the necessary tools
Any serious work with technology begins with organizing the space. You will need a sturdy workbench or table that won't wobble when hit. A refrigerator compressor is a heavy unit, often weighing between 8 and 12 kilograms, so securing it is critical. Lack of normal lighting can lead to injuries or loss of small but important parts.
The set of tools should be selected in advance so as not to interrupt the process with searches. Pay special attention to the cutting tool, since it is this that will do the dirtiest work on metal.
- 🛠️ An angle grinder (grinder) with a thin cutting disc for metal is the main tool for opening.
- 🔨 A hammer and a set of screwdrivers (flat and Phillips) for dismantling attachments.
- 🧤 Safety glasses and gloves are a must-have item of equipment when working with metal shavings.
- 🔌 Multimeter for checking the motor windings before disassembly.
It is worth mentioning separately respiratory protection. When cutting old metal and working with possible rust, fine dust is formed, which is extremely undesirable to inhale. If you have a respirator, be sure to use it.
⚠️ Attention: Before starting any work, make sure that the compressor is completely disconnected from the power supply. Even if you are planning only mechanical disassembly, the risk of accidental switching on or residual voltage in the capacitors of the starting relay has not been canceled.
Prepare a container for draining the oil. Even if the unit has not been working for a long time, there may be several hundred milliliters of technical oil inside, which should not get on the floor or clothes. Think in advance where you will put the metal filings so that they do not scatter throughout the room.
Removing attachments and starting relay
The first step is to free the main part of the body from additional elements. On the back wall of the compressor there are usually pipes, a start relay and a safety thermostat. These elements are attached quite simply, but require careful handling.
Start with a visual inspection. Locate where the electrical wire enters the plastic housing of the relay. Often there is a locking bracket or latch. Using a flathead screwdriver, carefully pry it off and remove the cover to gain access to the terminals. Remember or take a photo of the connection diagram if you plan to check the performance of the windings in the future.
Remove the start relay and thermal relay. They are usually simply put on the contacts of the compressor and are held in place by a tight fit or plastic clips. If the relay has become stuck over time, do not pull it by force - it is better to gently shake it from side to side or slightly warm it with a hairdryer so that the plastic becomes more elastic.
Now we move on to the copper tubes. If the compressor still contains freon, it must be vented in a well-ventilated area or outside. To do this, file one of the tubes. A characteristic whistle will indicate the release of gas. Only after the pressure is equal to atmospheric pressure can you cut the tubes with side cutters or saw them off with a grinder, leaving small “stumps.”
⚠️ Attention: When cutting down tubes, use only a hacksaw or grinder at low speed. Do not use cutters that can crush the end of the tube if you plan to use it, and do not allow chips to get inside the pipes.
Remove the rubber shock absorbers on which the motor hangs inside the casing. Usually there are three or four. They can be pressed down heavily by the weight of the unit, so they will have to be removed with force, perhaps using pliers. After this, the “black barrel” will remain free and can be moved for further cutting.
Opening a sealed casing: technologies and risks
The most crucial moment is breaking the seal of the casing. Factory welding is performed around the junction of two hemispheres. Your task is to cut this seam without damaging the internal windings or dropping metal shavings inside the housing. Chips inside a running engine are guaranteed death of the bearings and piston group.
There are several approaches to this operation. The most common is to use a grinder with a thin disk. Hold the tool at a 90-degree angle to the surface, being careful not to go deeper than the thickness of the metal. Guide the cutter strictly along the weld. If the cut is too deep, you risk damaging the stator winding, located close to the wall.
An alternative method is drilling. Holes are drilled around the perimeter of the seam close to each other, after which the top cover is removed. This method is cleaner, but requires more time and skill in working with a drill. Regardless of the method, remember about intrinsic safety.
☑️ Safely opening the casing
After the seam is passed in a circle, the cover may not be removed immediately. It often gets stuck at several points or is held in place by rust. Take a flathead screwdriver and a hammer, carefully insert the tip into the cut and try to loosen the halves with light taps. Do not use excessive force to avoid deforming the edges if you plan to reassemble.
Once the cover is removed, the internal structure will be revealed to you. Here it is important to immediately blow out the insides with compressed air to remove any small particles of metal that may have entered during cutting. Inspect the windings for melting or black spots - these are signs of an interturn short circuit.
Diagnostics of the internal mechanical part
Inside the casing there is the engine itself with a piston group attached to the shaft. This entire structure is mounted on springs or rubber hangers. The mechanical part consists of a cylinder, piston, crankshaft and valve system. This is where the causes of noise or lack of compression most often lie.
First, inspect the valve group. It is located on top of the cylinder and is covered with a metal plate fastened with two or three screws. By unscrewing them, you will have access to the suction and discharge valves. Usually these are thin elastic plates.
- 🔍 Check the integrity of the valve reeds - they should not have cracks or creases.
- 📏 Measure the gap between the piston and the cylinder mirror using feeler gauges if there is a suspicion of wear.
- 🧹 Assess the condition of the oil — the presence of metal shavings in the oil indicates the destruction of the sliding bearings.
If the valves are intact but there is no compression, the problem may be in the piston rings or the cylinder itself. At home, it is almost impossible to restore the geometry of the cylinder. However, if you disassembled the unit for use as a compressor for inflating tires, then the wear of the rings is not as critical as for the refrigeration cycle.
Why does it hum but not pump?
If the motor hums, but does not start or does not create pressure, the piston may be stuck at a dead point or the starting winding may have burned out. Another common cause is a broken connecting rod that connects the piston to the crankshaft. This is visually visible immediately after removing the cylinder cover.
Pay attention to the engine mounting system. The springs on which the motor hangs may burst or lose elasticity over time. This leads to the fact that during operation the engine begins to bang against the walls of the casing, creating a terrible roar. Replacing the springs solves the noise problem, but requires precise installation of the motor in place.
Electrical part and checking the windings
The electric compressor motor is an asynchronous motor with a squirrel-cage rotor. It has two main windings: working and starting. Checking their integrity is a mandatory diagnostic step before attempting to start or after disassembling.
To check, you will need a multimeter switched to resistance measurement mode (Ohms). On the contacts where the relay fits, you will find three terminals. Usually they are marked, but if there is no marking, you will have to ring the pairs.
There must be some kind of resistance between any two terminals. If the device shows one (infinity), it means the winding is broken. If zero - short circuit. The resistance of the starting winding is always higher than that of the working winding. Typical values can vary from 10 to 40 ohms depending on the model.
| Measurement type | Normal reading | Malfunction |
| :--- | :--- | :--- |
| Working winding | 10-20 Ohm | Open circuit or short circuit |
| Start winding | 30-50 Ohm | Open circuit or short circuit |
| Housing and windings | Infinity (∞) | Breakdown to the body |
| Resistance between terminals | There is a meaning | No contact |
⚠️ Attention: Never try to start the compressor by connecting it directly to a 220V network without a starting relay and capacitor (if provided). This will lead to humming, overheating and eventual burning of the windings.
It is also critical to check the resistance between the winding terminals and the copper tubes (housing). The device should show infinity. If there is at least some resistance, it means that the insulation is broken, and operating such a motor is dangerous to life.
Assembly, sealing or adaptation to other needs
If your goal was to repair the refrigerator, then after replacing defective parts (valves, springs), the assembly stage begins. Here the main problem arises: how to seal the case? Factory argon welding at home is not available to most.
Enthusiasts use different methods. Some people carefully weld the seam with a gas torch and solder, but this requires skill so as not to melt the thin metal of the casing. Others use epoxy compounds with fiberglass reinforcement, but this method does not guarantee durability against vibrations and pressure changes.
For use as a source of compressed air (airbrush compressor), the tightness of the casing is not as important as the reliability of the cover. You can drill holes around the perimeter and tighten the halves with bolts, laying a rubber gasket. This will allow you to disassemble the unit again in the future to change the oil or clean it.
Don't forget about changing the oil. During disassembly, the old oil is drained and must be replaced with fresh oil. For refrigeration compressors, special synthetic or mineral oil is used (for example Frige or analogues), which does not react with freon. Regular motor oil is suitable for the air compressor.
⚠️ Attention: Compressor specifications may vary depending on the manufacturer and year of manufacture. If you change the oil, make sure that its viscosity meets the requirements of a specific model, otherwise an increased load on the friction units is possible.
At the end of the assembly, if you plan to use the unit in the cooling system, the procedure of evacuation and charging with freon is mandatory. It is impossible to do this efficiently without professional equipment, so disassembling a refrigerator often becomes a point of no return, turning it into a source of spare parts or a pump.
Frequently asked questions (FAQ)
Is it possible to restore a compressor if it is jammed?
At home it is extremely difficult. If jamming occurs due to water hammer or solid particles, careful disassembly and cleaning sometimes helps. If the crankshaft liners are turned or there is scuffing in the cylinder, then repair is not practical without a lathe and boring.
What kind of oil should be poured into the compressor after disassembly?
To work with freon (in the refrigerator), you need a special refrigeration oil that matches the type of refrigerant (mineral for R12, polyester for R134a/R600a). If the compressor is converted to air, you can use regular compressor or motor oil with a viscosity of 10W-40.
Why did the compressor become louder after assembly?
Most likely, the alignment of the engine inside the casing is disturbed or the suspension springs are damaged. The cause may also be insufficient tightening of the cover mounting bolts or debris getting between the moving parts. Check whether the tubes touch the walls of the case during vibration.
Is it possible to solder the case back without welding?
It is impossible to properly solder a thick steel seam with a soldering iron. Two-part metal-filled epoxy adhesives can be used, but such a joint will not withstand the prolonged cyclic pressure and vibration of a full refrigeration cycle. For an air pumping compressor, this option is acceptable.