The situation when the refrigerator stops freezing, and inside there is silence or an intermittent humming is heard, which always takes you by surprise. Often the cause of a breakdown is a failure compressor, which is the heart of the entire refrigeration system. Many equipment owners immediately call a technician, but experienced home craftsmen can cope with replacing the motor themselves if they have basic skills in working with tools.
Replacing an engine is a complex technical process that requires not only mechanical replacement of the part, but also working with refrigerant, as well as hermetically sealed soldering of copper pipes. It is worth considering that without special equipment, such as a vacuum pump and a pressure gauge station, it is almost impossible to complete the work efficiently. However, understanding the principles and sequence of actions will help you assess the scale of work or carry out diagnostics before the arrival of a specialist.
In this article we will analyze in detail the stages of dismantling the old unit, preparing a new motor and the process of installing it. You will learn what to look for when choosing a spare part and how to avoid common mistakes that can lead to repeated breakdowns. Safety when working with electricity and gas under pressure should be priority number one.
Diagnostics and selection of a new compressor
Before buying a new part, you need to make sure that the problem lies in the motor. Often the symptoms of a compressor malfunction are similar to a broken start relay or thermostat. If the engine hums but does not start, or starts for a few seconds and turns off, this may indicate a jammed piston group or an inter-turn short circuit in the windings.
⚠️ Attention: Before any diagnostics, be sure to disconnect the refrigerator from the power supply. Working with live electrical wiring is deadly.
For an accurate check, you need to ring the windings with a multimeter. Normal resistance between contacts is usually between 20 and 60 ohms, depending on the model. If the device shows an open or short circuit, replacement is inevitable. When choosing a new motor, it is critical to consider the following parameters:
- 🔌 Power: must match the chamber volume and system requirements.
- 🧊 Type refrigerant: R134a, R600a or R12 (freon must match).
- 📏 Dimensions and seats: so that the motor fits into its original place without modifications.
- 🏭 Manufacturer: original spare parts Whirlpool, LG or high-quality analogues Danfoss, Secop.
You shouldn’t chase at the lowest price, buying dubious Chinese analogues without labeling. The discrepancy between the performance of the pump part and the heat exchanger (condenser/evaporator) will lead to rapid overheating and failure of even a new compressor. It is better to choose a part recommended by the manufacturer of your refrigerator.
Necessary tools and workplace preparation
To carry out the work, you will need a specialized tool, which is not always in the home craftsman’s kit. The basic list includes a gas torch (propane-oxygen or MAPP), pipe cutter, roller, wrench set, and pliers. It is also necessary to have a pressure manifold and a vacuum pump to create a vacuum in the system.
The work place must be well ventilated, since during soldering and the possible release of freon, harmful compounds can form. If you work indoors, provide forced ventilation. All flammable items must be removed away from the soldering area.
☑️ Preparing to replace the compressor
Pay special attention to preparing the new compressor. You cannot rely on transport plugs - before installation, it is better to remove them and blow them with nitrogen to make sure there are no chips inside. Vacuuming systems before refueling is a mandatory step, without which the moisture remaining in the tubes will turn into ice and block the capillary.
Removing the old compressor
The process of removing the old motor begins with access to the rear of the unit. Remove the protective panel by unscrewing the mounting bolts. You will see a compressor, a condenser grille and a tube system. The first step is to bleed off any remaining refrigerant. To do this, a neat puncture or cut is made in the sealed service tube, after which the gas comes out with a characteristic whistle.
Next, the copper tubes suitable for the compressor should be unsoldered. Use a torch to heat the soldering area evenly and carefully pull the tube with pliers. Do not allow an open flame to come into contact with the paintwork of the refrigerator body - this may cause a fire or deformation of the plastic.
| Type of tube | Function | Dismantling features |
|---|---|---|
| Suction | Supply of gaseous freon | Usually of a larger diameter, often covered with frost |
| Discharge | Discharge of compressed freon to the condenser | Small diameter, high temperature during operation |
| Service (refueling) | For vacuuming and refueling | Soldered at the end, used for first access |
After disconnecting the tubes, unscrew the mounting bolts or nuts that secure the motor to the frame. Sometimes the compressor is mounted on spring hangers inside the housing, which requires special care when removing it so as not to damage the internal pipes.
Installing and soldering a new motor
Installing a new unit is done in the reverse order of removal. Secure the motor to the frame using standard fasteners. If the rubber damper feet have become unusable, they must be replaced in order to reduce the level of vibration and noise during operation.
The most critical stage is soldering the connections. The tubes must be cleaned to a shine, treated with flux and heated with a burner. The solder should melt from the temperature of the tubes, and not from the flame of the burner. The quality of the seam is checked visually: it should be smooth, without cavities and sagging.
Safety precautions when soldering
When working with an open flame, always have a fire extinguisher on hand. Never leave a burner on unattended. Copper has high thermal conductivity, so keep the flame as far as possible from the plastic elements of the refrigerator, using reflective sheet metal screens.
After soldering all connections, the system must be checked for leaks. To do this, nitrogen is supplied under pressure (usually 10-15 atmospheres) through the service valve. A soap solution applied to the seams will help identify leaks by the bubbles that appear. Only after making sure of the tightness can you proceed to the next stage.
Evacuation and refrigerant charging
Evacuation is the process of removing air and moisture from the refrigerator circuit. Connect the vacuum pump to the service port and turn it on. The process should last at least 30-40 minutes. The residual pressure should be around 0.02-0.05 mbar. This is critical because moisture in the system freezes in the capillary tube, causing an ice lock.
After creating a vacuum, the system is charged with refrigerant. The amount of freon is strictly regulated by the manufacturer and is indicated on a label located on the back wall or inside the chamber. Refueling is carried out on scales with an accuracy of grams. Overfilling or underfilling freon will lead to incorrect operation of the refrigerator.
⚠️ Attention: It is prohibited to fill the refrigerator “by eye” or by pressure without weighing. The pressure in the system depends on the ambient temperature and is not an accurate indicator of the amount of refrigerant.
For refilling, use only the type of freon for which the compressor is designed. Mixing different types of refrigerants (for example, R134a and R600a) is strictly prohibited, as this leads to a chemical reaction, oil destruction and explosion hazard.
Starting and testing the system
After refueling, it is necessary to solder the service tube. Plug in the refrigerator and let it work. In the first minutes of operation, listen to the motor: it should run smoothly, without knocking or strong vibration. Check the heating of the condenser (grid at the back) - it should heat up evenly along its entire length.
Control the temperature in the chambers for 2-3 hours. A working refrigerator should reach operating temperature. If the motor runs continuously for more than 2 hours without turning off, and the temperature does not drop, there may be air left in the system or the amount of refrigerant is incorrect.
Successfully replacing the compressor extends the life of the refrigerator for many years. However, remember that this is a complex engineering task that requires precision and adherence to technology. If you doubt your abilities at any stage, it is better to entrust the work to professionals.
Frequently asked questions (FAQ)
Is it possible to replace an R134a compressor with an R600a compressor?
No, this is impossible and dangerous. These refrigerants have different physical and chemical properties and require different types of oil and compressor design. Using the wrong freon will lead to destruction of the cooling system.
Why does the refrigerator not freeze after replacing the motor?
There may be several reasons: poor-quality soldering (solder blockage), insufficient vacuuming (wet plug), incorrect amount of freon, or malfunction of the new compressor. Repeated diagnostics with pressure gauges is required.
How long does it take to replace a compressor?
For an experienced technician with ready-made equipment, the process takes from 1.5 to 3 hours, including time for evacuation and leak testing. At home, without experience, this may take much longer.
Is it necessary to flush the system when replacing a compressor?
Yes, if the old compressor burned out or jammed, combustion products or metal shavings could get into the system. Flushing with nitrogen or a special solvent is mandatory, otherwise the new motor will quickly fail.