An old refrigerator that has failed or simply served its useful life often ends up in a landfill, although its “heart” - compressor - may get a second life. Many home craftsmen and amateur engineers are looking for ways to recycle equipment wisely, turning powerful electric motors into the basis for compressor stations, airbrushes or pneumatic systems. However, the process of removing this unit requires not only physical effort, but also a clear understanding of the structure of the unit.
Before starting work, you need to realize that refrigeration compressor is a sealed unit, inside which high pressure is created and refrigerant circulates. Improper operation may result in personal injury or damage to valuable components. In this article we will look in detail at how to safely dismantle the engine, what tools will be needed and what you should pay special attention to when working with Germanika, Atlant or Stinol.
The success of the operation directly depends on the preparation of the workplace and the availability of suitable tools. You should not try to do the work on your knees or using inappropriate objects such as kitchen knives. Below we will look at all stages of the process, starting from disconnecting the device from the network and ending with the final cleaning of the contacts for further use of the motor in your projects.
Safety precautions and workplace preparation
The first and most critical stage is to ensure your own safety. There may be residual pressure inside the system, and the oil used to lubricate the rubbing parts is technical and toxic if in contact with skin or heated. It is necessary to work in a well-ventilated area, preferably in a garage or outdoors, to avoid inhaling freon vapors or insulation combustion products.
⚠️ Attention: It is strictly forbidden to open the compressor housing with a grinder or saw if there is refrigerant left inside. When exposed to an open flame or spark, it can form the poisonous phosgene gas. First, make sure that the system is completely depressurized by puncturing the tubes.
For comfortable work, you will need a stable workbench or a wide board laid on bricks. The floor must be level so that the heavy unit does not fall during manipulation. It is also worth preparing a container in advance to drain old compressor oil, which may leak during disassembly. Do not forget about personal protective equipment: thick gloves and glasses are required.
Pay special attention to the electrical part. Even if the refrigerator is unplugged, charged capacitors could remain in the power circuit, although this is rare in older models. However, checking the absence of voltage with a multimeter will not be superfluous. All manipulations with electric motor carry out only after completely disconnecting from the 220V network.
Necessary tools for dismantling
The set of tools for disassembling the compressor is quite standard, but requires a certain quality of workmanship. A cheap tool can lick the edges of the bolts or break at the most inopportune moment, which will delay the process. The basis of your arsenal will be mechanical devices for cutting metal and working with fasteners.
- 🔧 A set of open-end and socket wrenches (sizes from 8 to 19 mm) for unscrewing fastening nuts.
- ✂️ Wire cutters or side cutters with sharp edges for cutting copper tubes.
- 🔨 A hammer and chisel (or an old chisel) for carefully opening the casing if you need access inside.
- 🧤 Long-nose pliers for removing small parts and dismantling the start relay.
If you plan to do more than just remove the compressor, and to disassemble its sealed housing for rework, you will need an angle grinder (grinder) with a thin metal disc. However, for standard removal of the unit from a refrigerator cabinet, hand tools are sufficient. Also, do not forget to prepare a rag for wiping surfaces from oil.
☑️ Checking readiness for work
It is important to have a multimeter on hand for subsequent checking of the motor windings. This will allow you to immediately assess the condition electric motor and understand whether it is worth using in the future. If the resistance of the windings shows an open or short circuit, further disassembly may not make sense, unless you need the housing itself or the mechanical part for other purposes.
Disconnecting the refrigerator and accessing the unit
The process begins with completely de-energizing the refrigerator. Unplug the power cord and move the appliance away from the wall to gain access to the rear panel. In most models, such as Indesit, Beko or LG, the compressor is located in the lower niche at the back, covered with a metal or plastic casing.
Remove the back cover by unscrewing the mounting screws around the perimeter. You will have a view of a black barrel-shaped compressor, condenser grille and tube system. Inspect the connections carefully. The tubes can be copper or aluminum, and their integrity is important if you plan to keep the compressor for use with freon in the future.
What to do if the screws are rusty?
If the cap mounting screws are rusted and won't come off, do not use excessive force to avoid tearing the cap off. Treat them with a penetrating lubricant (WD-40 or equivalent), wait 10-15 minutes, and then try again. As a last resort, the cap can be carefully cut off with a hacksaw, but proceed carefully so as not to damage the internal elements.
Before cutting or unscrewing the tubes, it is necessary to drain the oil. To do this, turn the compressor upside down (carefully so as not to damage the suspensions) and open one of the tubes. The oil will begin to flow out, and it must be collected in a prepared container. Dispose of the waste correctly, without pouring it into the sewer or onto the ground.
Dismantling the compressor and disconnecting the pipes
The most crucial moment is the physical separation of the compressor from the system. The tubes suitable for the unit are usually soldered with soft solder. If you don’t have a gas burner for accurate desoldering, you can cut them with powerful wire cutters or saw them with a hacksaw. Make a cut 2-3 cm from the compressor body to leave “tails” for future diagnostics or connection.
⚠️ Attention: When cutting the tubes, residual gas may escape from the system with a characteristic whistle. This is normal, but make sure there are no open flames nearby at this time. The gas is heavier than air and can accumulate in low points of the room.
After disconnecting the lines, the compressor remains supported only by the fastening elements to the frame of the refrigerator. Typically these are four studs with rubber shock absorbers and nuts. Unscrew the nuts with a wrench. If the rubber feet are stuck or soured, you can carefully pry them off with a flat screwdriver, being careful not to damage the rubber itself if you need it.
Now the engine is free. However, the thermal relay is still hanging on it. They are attached directly to the end of the motor shaft or to the side. Carefully remove the plastic or metal casing of the relay, after photographing or sketching the wiring diagram. This will come in handy if you want to start the engine later. starting relay and thermostat. They are attached directly to the end of the motor shaft or to the side. Carefully remove the plastic or metal casing of the relay, after photographing or sketching the wiring diagram. This will come in handy if you want to start the engine later.
Disassembling the starting relay and electrical parts
The starting relay is the key element that allows the engine to start. In older models it can be electromechanical (with a coil and contacts), in new ones it can be electronic. To disassemble a mechanical relay, simply pry off the plastic latches of the housing. Inside you will see a copper coil, a movable core and contacts.
If your goal is to gain access to the motor windings, then the relay must be completely removed. It is held on by three contacts coming out of the compressor housing. Gently pull the relay up, rocking it slightly from side to side. Do not use excessive force so as not to break off the ceramic insulation of the terminals.
Inside the relay itself there is often a capacitor (in some circuits) or thermal protection. The thermal relay is a bimetallic plate that opens the circuit when it overheats. Check these elements with a multimeter. If the relay contacts are burnt, they can be cleaned with fine sandpaper, which often returns the unit to operability.
Opening a sealed housing (for advanced)
The compressor housing itself is factory sealed. To get to the piston group and valves, it is necessary to saw the weld along the equator of the housing. This is done with a grinder with a thin disk. You need to cut strictly at the junction of two hemispheres, without touching the internal parts.
After cutting, remove the top cover. The mechanism will open in front of you: crankshaft, connecting rod, piston and cylinder. Here is discharge valve, which is often the cause of loss of productivity. It can be carefully removed, cleaned of carbon deposits, or replaced with a more efficient one if you are making a compressor for an airbrush.
| Component | Function | Possible problem | Solution for alteration |
|---|---|---|---|
| Piston group | Gas compression | Ring wear, scuffing | Lapping in or replacement |
| Valves | Flow direction | Burnout, loss of elasticity | Replacement with flap ones |
| Electric motor | Rotation shaft | Winding break | Rewinding (difficult) |
| Oil pump | Lubricating components | Clogged channels | Rinsing with kerosene |
When reassembling it (if you do not make it into an open-type compressor), welding the seam is impossible at home. Typically, the halves are bolted together through drilled holes, and the joint is sealed with heat-resistant sealant. However, such a unit is no longer suitable for working with freon under pressure, but will serve perfectly as a vacuum pump or compressor for inflating tires.
Diagnostics and use of parts
After disassembly, all parts should be thoroughly washed in gasoline or a special solvent to remove old oil and varnish deposits. Inspect the cylinder for scoring. If the cylinder bore is smooth, the engine will still serve. The motor windings are checked for resistance: between the common point and the starting/working winding it should be within tens of Ohms.
Copper from the windings is a valuable non-ferrous metal. If the engine burns out and cannot be restored, it can be scrapped. But first, make sure you remove all non-metallic inclusions. The steel body and copper winding are sold separately, since the price for them varies.
Do not throw away rubber shock absorbers. They are universal and can be useful for vibration isolation of other mechanisms. Also a valuable element is a copper tube, which, after annealing, becomes very soft and convenient for various homemade products.
Frequently asked questions (FAQ)
Is it possible to run a compressor without freon?
Yes, a compressor from a refrigerator works great as an air compressor. However, the oil that circulates in the system along with freon can be released along with the air flow. For use in pneumatics, it is necessary to install an oil separator and a filter at the outlet.
What kind of oil should be poured into a disassembled compressor?
Old Soviet compressors (type FG) were usually filled with freon oils HF12-16 or HF22-24. Modern units with R134a freon use synthetic POE (polyester) oils. When converting to air, regular 10W-40 motor oil is often used, but it can foam, so it is better to look for special compressor oils.
Why does the compressor hum, but does not start?
Most likely, the starting relay is faulty or the piston is stuck. If the relay is working properly, try to “swing” the shaft by briefly applying voltage. If this does not help, it may be necessary to disassemble the mechanical part to remove the wedge.
How many atmospheres can an old compressor produce?
Standard refrigeration compressors are designed for a condensation pressure of about 15-25 bar (atmospheres). However, in homemade receivers without automatic shutdown, the pressure can increase until the housing collapses. Be sure to install a pressure switch for safety.