The situation when the refrigerator stops working freeze, and the compressor is either silent or hums, but does not start, often leaves the owner with a choice: call a technician or try to solve the problem on his own. Replacement compressor is one of the most difficult procedures in repairing household appliances, requiring not only theoretical knowledge, but also the availability of a specific tool. If you are determined to carry out the work on your own, you will have to deal with soldering copper tubes, working with gas and high voltage electricity.
Do not underestimate the risks associated with breaking the tightness of the system. Incorrectly performed soldering or poor-quality vacuuming can lead to failure of the new unit after several months of operation. In addition, modern refrigerants, such as R134a or R600a, require strict adherence to dosage and system cleanliness. In this article, we will analyze the technical side of the process so that you understand the amount of work required and the required qualifications.
Before proceeding with dismantling, it is critically important to ensure that the start relay and thermostat are in good working order, since the symptoms of their failure are often confused with motor failure. If the diagnostics confirm that electric motor it is burnt out or jammed, then the only option is to replace it. Remember that working with open fire and flammable gases requires compliance with safety precautions and the presence of a working fire extinguisher near the workplace.
Diagnostics and preparation of the workplace
The first step is the final confirmation of the diagnosis. Often, users mistakenly believe that the refrigerator does not work because of the compressor, although the problem may lie in an open circuit or a burnt one. Check the resistance of the windings with a multimeter: if it approaches zero or infinity, the motor is faulty. It is also worth checking for a short circuit to the housing. start relay. Check the resistance of the windings with a multimeter: if it approaches zero or infinity, the motor is faulty. It is also worth checking for a short circuit to the housing.
The organization of the workspace plays a key role in the success of the operation. You will need a spacious, well-ventilated area, ideally a garage or open area, as the soldering and refueling process involves heat generation and possible release of residual gas. Prepare a stable surface where you can lay the unit on its side, providing access to the bottom.
⚠️ Attention: Before starting any work, be sure to unplug the refrigerator and defrost the chamber. The presence of water in the soldering system is unacceptable and will lead to explosive boiling of moisture inside the tubes.
To replace it, you will need a specialized tool, without which the process is impossible. The standard set includes a gas burner (preferably with MAP gas or propane-oxygen), a pipe cutter, a rolling machine, a pressure gauge station and a vacuum pump. Using improvised means, such as a hacksaw, can lead to chips getting into the system, which is fatal for a new compressor.
Necessary tools and materials
The quality of the work directly depends on the equipment used. Cheap analogue instruments often do not provide the necessary tightness of connections or accuracy of readings. Pay special attention to the choice solder: to connect copper tubes with steel compressor pipes, you need refractory solder containing silver, for example PhosAg 40% or CuP6.
The list of required materials and tools includes not only a basic set, but also consumables. You will need nitrogen for purging (or dry air), filter driers and, of course, the refrigerant itself in the cylinder. It is absolutely impossible to start the system without a filter-drier, since the moisture that got inside during soldering will freeze in the capillary tube and clog the system.
- 🛠️ Gas burner with a set of nozzles for uniform heating.
- 🔩 Pipe cutter and rolling set for copper pipes.
- 🧪 Pressure gauge station with hoses for R134a or R600a.
- 💨 Vacuum pump to remove air and moisture from the circuit.
- ⚖️ Electronic scales for accurate refrigerant charging.
The choice of the compressor itself requires special attention. It must strictly match the model of your refrigerator in terms of power, type of refrigerant and overall dimensions. Use analogues is permitted, but only if their technical characteristics completely coincide with the original. An attempt to install a more powerful motor can lead to an overload of the electrical network and melting of the wiring.
Removing the old compressor
The process of removing the old unit begins with carefully cutting off the copper tubes. Do not try to unscrew connections if they are made by soldering - this is impossible without damaging them. Step back 10-15 cm from the compressor housing and saw through the tubes with a pipe cutter. It is important to do this so that dust and debris do not get into the open ends of the tubes.
After freeing the lines, it is necessary to disconnect the electrical part. Remove the start relay cover and disconnect the terminals. Wires often become stuck or oxidized, so be careful not to break them at the base. Remember or take a photo of the connection diagram, although on new models the relays often have universal markings.
⚠️ Attention: Residual refrigerant pressure may remain in the system. When depressurizing, a sudden release of gas with a characteristic hissing is possible. Protect your eyes and do not inhale freon vapors.
When the tubes are cut and the wires are disconnected, unscrew the compressor from the refrigerator frame. It is usually mounted on four bolts with rubber shock absorbers. Check the condition of these shock absorbers: if they have dried out or lost elasticity, they must be replaced, otherwise the new compressor will operate with increased noise levels.
What to do with the used oil?
Drain the oil from the old compressor into a sealed container container. It should not be poured down the drain or onto the ground. Used refrigerant and oil are hazardous waste and require special disposal at collection points.
Preparation and installation of a new unit
Installation of a new motor begins with the preparation of fittings. On modern compressors they are often closed with plastic plugs, which must be removed immediately before soldering. If you are using a compressor with a type of refrigerant R600a (isobutane), be extremely careful, as this gas is explosive when concentrated in air.
Before soldering, it is necessary to clean the copper tubes from oxides and dirt. Use fine sandpaper or a special copper cleaner. The surface should be shiny and smooth. Also prepare the fittings or use the copper-steel soldering method, which requires a special flux and quick work so as not to burn out the steel tube.
An important step is to install a new filter drier. It is mounted on the liquid line (output from the condenser) before entering the capillary tube. The filter has an arrow in the direction of movement of freon, which cannot be confused. The time between removing the filter plugs and the start of soldering should be minimal so that adsorbent no moisture from the air accumulates inside.
☑️ Ready for soldering
Technology for soldering connections
Soldering is the most critical stage that determines the tightness of the system. To connect the copper tube to the steel compressor pipe, the heating must be uniform. First, the steel part is heated, since it has a higher heat capacity, and only then is solder introduced into the contact area. It should flow into the gap under the action of capillary effect, and not just spread over the surface.
When working with the burner, avoid overheating. The flame should be directed at the joint, but not at the tube itself away from the joint. If you are using silver solder, flux is often not needed, but for copper-to-steel joints, using flux makes the process easier. The main thing is to prevent the thin wall of the copper tube from burning through.
After the connection has cooled, it must be checked visually. The seam should be smooth, without cavities or sagging. Any roughness may indicate a potential leak. Immediately after soldering all connections, it is recommended to carry out an initial pressure test with nitrogen in order to identify gross defects before evacuation.
⚠️ Attention: Never solder connections that are under pressure or with refrigerant residues inside. This will lead to ignition of the gas and a chemical reaction that destroys the oil and insulation of the windings.
Evacuating and charging with refrigerant
Evacuating the system is a mandatory procedure that cannot be ignored. It is necessary to remove air and, more importantly, water vapor. The water in the refrigerator system turns into an ice plug in the low pressure zone (capillary tube), blocking the circulation of freon. Connect the vacuum pump to the service connection and turn it on.
The vacuuming process should last at least 30-40 minutes. The low pressure gauge (blue) should show a value in the vacuum zone (below -1 bar or 750 microns). If the arrow begins to creep up after turning off the pump, it means that there is a leak in the system that needs to be eliminated.
Refrigerant is charged strictly according to the weight indicated on the information sticker of the refrigerator (usually on the inner wall or back). Using a cylinder without a scale is unacceptable, since it is impossible to determine the required amount by eye. Overfilling will lead to an increase in condensation pressure and overload of the compressor, and underfilling will lead to insufficient cooling.
| Parameter | Value / Action | Note |
|---|---|---|
| Refrigerant type | R134a or R600a | Look on the compressor nameplate |
| Filling weight | 60 - 140 grams | Depends on chamber volume |
| Suction pressure | From -0.1 to -0.2 bar | In operating mode |
| Current consumption | 0.5 - 1.2 Ampere | Control with current clamps |
Tightness check and test run
The final stage is checking all connections for leaks. Even if the seam looks perfect visually, a microscopic crack can ruin all the work. Use a soap solution or a special leak detector spray. Apply foam to the solder joints and observe for a few minutes. The appearance of bubbles indicates a leak.
After successfully checking the tightness and refueling, you can make the first start. Plug in the refrigerator and monitor current consumption using a current clamp. It must correspond to the value specified in the documentation. In the first minutes of operation, the compressor may be noisier than usual until the system reaches operating mode.
Evaluate the operation of the refrigerator in dynamics. After 30-40 minutes of operation, the evaporator inside the chamber should begin to become covered with frost (“cap”), and the condenser (grid at the back) should begin to heat up evenly. If the cold zone appears only at the outlet of the evaporator, there may be air left in the system or the capillary tube is clogged.
⚠️ Attention: Specifications and sealing requirements may vary slightly depending on the manufacturer of the refrigerator. Always check the service documentation for your specific model before final assembly.
How long does it take to replace a compressor?
In a professional workshop with all the tools, the process takes from 1.5 to 3 hours. At home, without experience, this can take a whole day, including time for searching for tools and materials.
Is it possible to refill a refrigerator without scales?
Theoretically, experienced craftsmen are guided by pressure and current, but for a beginner this is unacceptable. Without scales, you can make a critical error in the dosage, which will lead to breakdown of the new compressor.
Does the system need to be flushed when replacing?
Yes, if the old compressor burns out, acidic oil and combustion products remain in the system. Flushing with nitrogen under pressure is mandatory, otherwise the new motor will burn out in a few months.
Which solder is best to use?
For a copper-to-copper connection, ordinary copper-phosphorus solder is suitable. To connect copper-steel (compressor pipes), you need solder with a silver (Ag) content of at least 15-30% and the use of flux.
What to do if the compressor gets very hot?
Heating to 80-90 degrees is normal for a piston compressor. If it heats up to the point where you can’t touch it, or knocks out the thermostat, check the current, the cleanliness of the capacitor and the correct freon filling.