Compressor failure is one of the most serious and costly malfunctions that a home appliance owner can encounter. When refrigerator motor stops starting, hums without cooling, or constantly clicks, often the only solution is to completely replace it. This is a complex technical process that requires not only physical effort, but also specific tools, such as a torch, a pressure gauge station and a vacuum pump.
Before you begin, you must clearly understand that you are dealing with a closed system under pressure and high voltage electrical components. Inverter compressor or a conventional piston unit requires careful handling of refrigerant and oil. In this article we will analyze all the stages of dismantling the old unit and installing a new one so that you can assess your strengths and risks.
It is worth noting that the success of the operation depends not only on the correct connection of the tubes, but also on the quality of the materials used. Using the wrong oil or improper soldering of copper tubes is guaranteed to lead to repeated failure of the equipment within a few weeks. Therefore, carefully study the theoretical part, prepare the working place and only then pick up the tools.
Diagnostics and signs of compressor malfunction
Before buying a new unit, you need to make sure that the problem lies precisely in it, and not in the control or thermoregulation system. Users often confuse a motor breakdown with a faulty start relay or thermostat. If you hear that refrigerator unit tries to start, makes a click and goes silent, this may indicate a jammed piston group or breakdown of the windings.
For accurate diagnostics, technicians use a multimeter to check the resistance of the windings. Normal readings vary depending on the model, but an open circuit or short circuit (resistance close to zero) indicates a fatal failure. It is also worth checking whether the current is passing through the housing, which is especially dangerous to life.
⚠️ Attention: If traces of oil are visible on the compressor housing or it is severely deformed, it is prohibited to operate such a refrigerator. This may indicate a freon leak or a leak in the system.
It is important to distinguish between the symptoms: if the engine hums but does not start, there may be a problem with the starter. However, if after replacing the relay the situation has not changed, and the motor shaft does not rotate even with a short-term voltage supply, then replacing the refrigerator compressor becomes inevitable.
Necessary tools and materials for replacement
High-quality repairs impossible without specialized equipment. You will need not only a set of wrenches, but also tools for working with copper tubing. The main tool will be a gas torch with a solder kit, since the connection of the tubes must be sealed and withstand high pressure.
To work with refrigerant, a pressure gauge station (manifold) and a vacuum pump are required. Without creating a vacuum, moisture and air will remain in the system, which will lead to the formation of ice plugs and corrosion of internal parts. You will also need refill bottle a brand of freon that matches your refrigerator (R134a, R600a or R12).
- 🔧 A gas burner and a gas bottle for soldering copper connections.
- 🌡️ Manometric station for monitoring pressure and vacuuming.
- 🧪 Vacuum pump to remove moisture and air from the circuit.
- ⚗️ Refrigerant cylinder and scales for precise charging.
- 🔩 Nippers, pipe cutter and rolling machine for preparing copper pipes.
Don't forget to prepare a new compressor that fully matches the technical characteristics of the old one. The power, refrigerant type and overall dimensions must match. Using analogues is possible, but requires recalculating the length of the capillary tube, which is a task for professionals.
Preparing the refrigerator and dismantling the old unit
Work should begin only after completely disconnecting the device from the power supply. Unplug the cord and move the refrigerator away from the wall, allowing easy access to the back. Remove the protective casing covering the engine compartment and let the equipment cool down if it has been recently operated.
The first step is to bleed off the refrigerant. This must be done in a well-ventilated area or outdoors, as the gas can be dangerous if inhaled in high concentrations. Carefully bite the copper tube next to the compressor so that the gas comes out, and immediately clamp the ends of the tubes to prevent air and moisture from getting inside.
☑️ Preparation for dismantling
Next, you need to unsolder the condenser and evaporator from the compressor pipes. Heat the soldering area with a torch evenly until the solder becomes soft and carefully separate the tubes. Be careful, there may be oil inside under pressure. After disconnecting the tubes, unscrew the mounting bolts holding the engine to the frame and remove it.
⚠️ Attention: When unsoldering the tubes, direct the burner flame strictly to the connection, avoiding overheating of the compressor body itself, as this can damage the internal insulation of the windings.
If used in the system mineral oil, it could be partially mixed with decomposition products during combustion, so it is better not to use a new compressor with old components without thoroughly flushing the system. However, if the replacement is planned due to wear and tear, just make sure that the condenser and filter drier must also be replaced.
Installing a new compressor and soldering connections
Installing a new engine is done in the reverse order of dismantling. Secure the unit to the frame using the standard mounting holes and shock-absorbing bushings. This is critical for reducing noise and vibration during operation. Vibration can destroy copper tubes if they are strained.
Before soldering, it is necessary to remove the process plugs from the pipes of the new compressor. Insert the copper condenser tubes and discharge tube into the corresponding holes. The gap between the tube and the pipe should be minimal, but the tube should not rest against the bottom. For a reliable connection, use silver solder or special fluxes for copper.
Be sure to replace the filter drier. This element is responsible for removing moisture from the system, and when depressurized, it becomes saturated with water, losing its properties. Install a new filter at the condenser outlet before entering the capillary tube. Solder the filter quickly so as not to overheat its housing.
| Refrigerant type | Discharge pressure (bar) | Oil type | Features |
|---|---|---|---|
| R134a | 8.5 - 9.5 | Synthetic (POE) | Hygroscopic, afraid of moisture |
| R600a | 5.5 - 6.5 | Mineral | Explosive, requires ventilation |
| R12 (old) | 9.0 - 10.0 | Mineral | Prohibited, replaced by R134a |
| R404a | 14.0 - 16.0 | Synthetic | High pressure, for freezers |
After soldering all connections, the system is considered mechanically assembled. However, it is too early to launch it. It is necessary to check the tightness of the seams by purging the system with nitrogen under pressure. If the pressure drops, it means that somewhere there is a fistula that needs to be found and soldered.
Why can’t you solder without nitrogen?
When soldering copper tubes, an oxide film (scale) forms inside. If you flush the system with nitrogen during soldering, there will be no oxides. Scale can clog the capillary tube or filter, which will lead to compressor failure after a month of operation.
Evacuation and refrigerant charging
The most important stage is creating a vacuum. Connect the vacuum pump hose to the service connection and turn on the pump. The process should last at least 30-40 minutes. This is necessary to evaporate moisture that may have entered the system during installation. The water in the system freezes in the capillary and blocks the freon flow.
After evacuation, close the valve on the manifold and turn off the pump. If the pressure gauge needle remains in place (shows deep vacuum) for 15-20 minutes, then the system is sealed. If the arrow creeps up, it means that there is a leak somewhere that needs to be repaired.
Refrigerant is charged strictly according to the weight indicated on the refrigerator label. Use electronic scales to control the amount of gas being charged. Overfilling the system with liquid freon can lead to water hammer and destruction of the compressor valves.
- 📉 Pump out the vacuum to -1 bar (or lower if the pump allows).
- ⏱️ Maintain the vacuum for 30 minutes to remove moisture.
- ⚖️ Fill the exact amount of refrigerant by scale.
- 🔥 Solder the service pipe after filling.
⚠️ Attention: Never fill the refrigerator “by eye” or by pressure without weighing. The pressure depends on the ambient temperature and is not an accurate indicator of the amount of freon in the system.
For inverter models the process may differ in the need for adjustment through the service mode, but the basic principles of evacuation remain unchanged. After refueling, solder the service pipe and wipe the soldering area with a damp cloth.
Startup and performance check
After completing all work, connect the refrigerator to the network. During the first minutes of operation, listen carefully to the sound of the engine. It should be smooth, without knocking, clanging or strong vibration. Current consumption Must correspond to the passport data (usually checked with a current clamp).
Check the heating of the condenser (grids at the back or on the sides). It should heat evenly along its entire length. If only part of it heats up, there may be air left in the system or the filter is clogged. Also check the operation of the evaporator inside the chamber - it should be covered with frost evenly.
Leave the refrigerator to work for several hours without loading food. Monitor the temperature in the chamber. If after 2-3 hours of operation the temperature does not drop to the required values, it may be necessary to adjust the amount of refrigerant or check the thermostat.
If all parameters are normal, you can carefully install the back cover and move the refrigerator to the place of use. Remember that after transportation and refueling the equipment may require several hours to stabilize operation.
Frequently asked questions (FAQ)
Is it possible to replace the compressor yourself without a vacuum pump?
Theoretically, some craftsmen use the method of “squeezing out” the air with freon itself, but this is extremely unlikely recommended. Without evacuation, moisture remains in the system, which will quickly disable the new compressor due to water hammer or an acid reaction with the oil.
How much does it cost to replace a refrigerator engine in a service?
The cost consists of the price of the new compressor, the cost of work and materials (freon, filter, solder). On average, this ranges from 50% to 80% of the cost of a new refrigerator, so it is often more advisable to buy new equipment.
Why can a new compressor burn out immediately after installation?
The main reasons: poor evacuation (moisture), scale getting into the system during soldering, using the wrong oil or incorrect refrigerant dosage. It is also important to check the serviceability of the start relay.
Is it necessary to flush the system when replacing a compressor?
If the old compressor burns out and releases oil into the system, flushing with nitrogen is mandatory. Oil combustion products are acidic and will quickly kill a new engine. If the replacement is planned due to wear, flushing is not required, just replacing the filter.