The situation when the refrigerator stops freezing and the temperature inside rises often frightens owners with the complexity and cost of the upcoming repair. However, if diagnostics show that the problem lies precisely in compressor, replacing this unit yourself can save a significant amount of money. This is not an easy task, requiring accuracy, special tools and compliance with safety precautions, but it is quite feasible for a person with a “direct” hand.
Before you begin to dismantle the old unit, you need to understand that you are working not only with electricity, but also with refrigerant. Freon, circulating in the system can be a fire hazard or asphyxiant, and high pressure in the circuit requires a special approach. In this article we will analyze the process of replacing a motor-compressor from A to Z, paying attention to the nuances that are often silent in service centers.
It is important to immediately note that the success of the operation depends not only on the quality of the new engine, but also on the correct preparation of the workplace. You will need to ensure good ventilation in the room and access to the back of the refrigerator from all sides. Inverter models or units with the No Frost system may have their own design features, but the basic replacement principle remains the same for most household refrigerators.
Fault diagnosis and selection of a new compressor
Replacing the compressor is a last resort measure that should be taken only after a thorough check. Often a failure of the starting relay or thermostat is mistaken for motor failure. If you hear a buzzing sound, clicks, but the start does not occur, or the motor runs constantly without cooling the chamber, there is a high probability that the piston group wedge is worn out. Before purchasing a new part, be sure to take readings from the nameplate of the old unit. pump part The piston group is worn or wedged. Before purchasing a new part, be sure to take readings from the nameplate of the old unit.
Selecting an analogue is a critical stage. You can’t just buy a compressor of the same power; The type of refrigerant, chamber volume and cooling capacity must be taken into account. Modern inverter compressors require configuration through service software, which makes replacing them at home almost impossible without dealer equipment. For older models with conventional piston engines, it is important that the geometric dimensions and seats match.
⚠️ Attention: Never install a compressor designed for R12 freon in a system where R134a or R600a was previously circulated. Different types of oils and refrigerants are incompatible and will lead to instant failure of the new part.
When choosing, pay attention to the country of origin and the availability of a service guarantee. Chinese analogues may cost less, but their resource is often inferior to the originals from Secop or Aspera. Also check the condition of the condenser and evaporator: if there was acid in the system after the windings burned out, simply replacing the motor without flushing the circuit will lead to repeated failure in a few months.
Necessary tools and workplace preparation
For a high-quality replacement of the compressor, a conventional set of household tools will not be enough. The key is to have the equipment to handle the copper piping and refrigerant. You will definitely need burner (gas or oxygen), a pipe rolling kit, a pipe cutter and a pressure gauge station. Without the latter device, it will be impossible to control the pressure when vacuuming and filling the system.
In addition to special tools, prepare consumables. This is a filter drier, which is changed every time the circuit is depressurized, and solder with flux. The use of tin for soldering copper tubes of a refrigerator is strictly prohibited due to the low melting temperature threshold and vibrations. Only silver solder or special phosphorus alloys will ensure the tightness of the connection for many years.
Organize your workspace so that the refrigerator can be easily tilted and rotated. Take care in advance of bright lighting of the lower part of the unit, where the technical components are located. All tools must be within reach so as not to interrupt the soldering or assembly process.
Removing the old compressor and preparing for soldering
The first step is always to completely disconnect the refrigerator from the power supply. Let the unit sit for a few hours to allow the refrigerant to redistribute, although this may be difficult if the compressor is faulty. Remove the rear protective panel and get to the motor. Carefully remove the starting relay and thermal protector, remembering their position, as they may be needed for testing or temporarily used with a new motor.
Now you need to bleed off the remaining freon. To do this, use a file or pipe cutter to make a small cut on the thinnest copper tube (filler). You will hear a characteristic hissing sound of gas escaping. After waiting until the pressure is equal to atmospheric pressure, you can start cutting the tubes. Use a high-quality pipe cutterso as not to deform the edges of the copper, which will make further soldering easier.
☑️ Preparation for dismantling
It will not be possible to unsolder the old compressor without a burner. Heat the joints between the tubes and the motor housing until cherry red, gently shaking the tube. Try not to overheat the compressor housing itself and adjacent elements. After removing the motor, inspect the condenser for black spots or oily marks, which may indicate leaks elsewhere in the system.
Installing a new motor and soldering connections
Installing a new compressor begins with preparing the tubes. Remove the transport plugs from the pipes of the new motor immediately before soldering to prevent air and moisture from getting inside. If you are using a compressor with plugged fittings, make sure that a slight positive pressure is maintained inside - this is a sign of leaks. Insert the compressor into the seat and secure it with fasteners, but do not tighten them completely until the tubes are aligned.
The soldering process requires skill. Heat the joint between the tube and the pipe evenly, then insert the solder rod. The molten metal should flow into the gap under the action of capillary effect, forming an even bead. Do not pour solder on top of a cold tube - this will create a “cold solder” that will flow under pressure. Pay special attention to installing a new filter-drier: it must be soldered quickly to minimize the time of contact with air.
| System element | Action | Important nuance |
|---|---|---|
| Suction tube | Soldering to the compressor | The tube should fit into the pipe by 10-15 mm |
| Discharge tube | Soldering to the condenser | The gap between the tube and the wall is 0.1-0.2 mm |
| Filter-drier | Installation in a circuit break | The arrow on the body should indicate the direction of flow |
| Refill fitting | Installation for vacuum | Position vertically for ease of connecting the station |
After soldering all connections, allow the copper to cool naturally. Do not pour water on hot areas, as this may cause microcracks. Visually check the quality of the seams: they should be smooth, without cavities or sagging. If you find a defect, it is better to redo the connection immediately than to look for a leak after filling with expensive gas.
What to do if the solder does not flow?
If the solder rolls up into balls and does not flow into the gap, it means that the surface is not sufficiently heated or oxidized. Add a little flux (for copper) or increase the flame of the torch, directing it to the bulk of the metal, and not to the solder itself.
Evacuation of the system and charging with refrigerant
The most critical stage is removing air and moisture from the circuit. The air remaining inside will create an “air lock”, increase the condensation pressure and lead to overheating of the compressor. The moisture, in turn, will freeze in the capillary tube, causing a blockage in the system. Connect the pressure gauge station to the service connection and turn on the vacuum pump. The evacuation process should last at least 30-40 minutes.
The pressure gauge readings should reach -1 bar (or close to it). If the arrow begins to creep up after turning off the pump, it means there is a leak in the system. Find and fix the leak, otherwise all the work will go down the drain. Only after successful vacuuming can you begin refueling. The amount of refrigerant is strictly regulated by the manufacturer and is indicated on the refrigerator tag.
⚠️ Attention: Filling “by eye” or by pressure without weighing is unacceptable. An excess of freon will lead to a liquid shock to the compressor, and a deficiency will lead to insufficient cooling and overheating of the motor.
Turn on the refrigerator and start supplying freon in small portions, monitoring the current consumption of the compressor with an ammeter. It should not exceed the nominal values specified in the passport. Monitor frost formation on the evaporator and condenser temperature. A properly charged system operates quietly, and the freezer reaches temperature in 30-40 minutes.
Typical errors and performance testing
Even experienced craftsmen sometimes make mistakes that negate the result of the repair. One of the most common is poor cleaning of the tubes before soldering. Copper oxides prevent a quality connection, and over time a fistula forms in this place. Another common mistake is installing a filter drier without observing the flow direction indicated by the arrow on the housing.
After assembly and startup, listen carefully to the operation of the unit. Extraneous knocks, metallic clanging or excessively loud humming indicate problems with the compressor mounting or internal defects. Check the temperature of the motor housing: it should be hot, but not scalding. If your hand does not tolerate touching for more than 2-3 seconds, the pumping may be broken or there is not enough oil.
Do not forget to test the tightness of all seams using a soap solution. Apply foam to the solder joints and wait a few minutes. The appearance of bubbles will indicate a micro-leak, which must be sealed after bleeding the gas. Ignoring this stage will lead to the gradual disappearance of freon and loss of cold after several weeks of operation.
Frequently asked questions (FAQ)
Is it possible to replace a compressor without a vacuum pump?
Theoretically, some “traditional craftsmen” are trying to purge the system freon or just bleed the air. However, without a vacuum pump it is impossible to remove the moisture contained in the air. The moisture will freeze in the capillary and the refrigerator will stop freezing after a few hours or days of operation. Evacuation is a prerequisite for the longevity of the repair.
How much does it cost to replace a compressor at a service center compared to doing it yourself?
In the service department, the cost consists of the price of the spare part, the work of the technician and the visit. Self-replacement allows you to save on work (usually 50-70% of the check amount), but requires the purchase or rental of a tool (burner, station, pump) if they are not available. For a one-time replacement, purchasing equipment may not be economically feasible.
Is it necessary to flush the system if the old compressor has burned out?
Yes, if the windings have burned out, acid and oil combustion products have entered the system. Simply replacing the motor without flushing with nitrogen or special solvents will result in acid quickly destroying the new compressor. In such cases, it is also recommended to install an additional suction filter-drier.
Which freon is better: R134a or R600a?
You cannot choose freon based on the “better/worse” principle. The system is designed for a specific type of refrigerant. R600a (isobutane) is more efficient and environmentally friendly, but is fire hazardous, which requires special safety measures when soldering. R134a is safer, but requires more precise dosage. Use only the gas specified by the manufacturer on the nameplate of your refrigerator.