Failure of the main unit of the cooling system is always stressful for the owner of household appliances, because the safety of food and the family budget are at stake. If you are looking for a way to replace the compressor in a refrigerator with your own hands and are studying video instructions, then you have already made a bold decision to take on the matter yourself. Diagnostics must be carried out carefully: extraneous knocking, failure to start or a hum without cooling often indicate a breakdown motor-compressor.
It is important to immediately understand the complexity of the upcoming operation, which requires not only mechanical skills, but also specific tools. For high-quality repairs, the use of nitrogen during soldering is mandatoryto prevent oxidation of the inner walls of the tubes, which is a critical condition for the durability of the repair. Without following the technology, the system can become clogged with oil and oxide breakdown products, which will lead to repeated breakdown in a short time.
In this article we will analyze all stages of work: from dismantling the old unit to recharging it with refrigerant, relying on proven methods of professionals. You will learn what tools are needed, how to choose the right analogue and why some steps should never be skipped. Preparing a theoretical basis is the first step to successfully restoring the functionality of your refrigerator refrigerator.
Diagnostics of the malfunction and selection of a new compressor
Before you begin disassembling, you need to make sure that the problem lies in the compressor, and not in the thermostat or start relay. It often happens that a serviceable engine does not start due to a burnt starting relay or broken thermostat circuit. Test the windings with a multimeter: if the resistance between the contacts is absent or equal to zero, then there is a break or short circuit.
Choosing a new spare part is a critical moment, since there are practically no universal solutions here. It is necessary to take into account the power, type of refrigerant (R134a or R600a), overall dimensions and method of mounting the paws. Model must correspond to the original or be a proven analogue recommended by the manufacturer for your series of refrigerators.
Pay attention to the type of compressor: they are piston and linear (inverter). Replacing a conventional piston engine with an inverter engine without replacing the electronic control module is impossible, since the principles of their operation are radically different. Below is a table for comparing the main parameters that need to be checked before purchasing.
| Parameter | Conventional compressor | Inverter compressor | Importance of checking |
|---|---|---|---|
| Principle operation | On/off | Smoothly changes power | High |
| Noise level | Medium/High | Low | Average |
| Energy consumption | Standard | Economical (Class A+) | High |
| Compatibility | Requires a relay | Requires an inverter unit | Critical |
How to read the markings on the nameplate?
The nameplate indicates: model (e.g. Secop Danfoss), voltage (220-240V), frequency (50Hz), refrigerant type (R134a) and cooling capacity (e.g. 136 W at LBP). Look for this data first.
When purchasing, pay attention to the condition of the shipping fittings - they must be sealed at the factory. If the tubes are open and air comes out from there, it means that moisture has already got inside, and such a unit cannot be taken. Moisture in the system it is the main enemy, which turns into acid and disables the new motor.
Necessary tools and preparation of the workplace
High-quality repairs is impossible without specialized equipment that goes beyond the standard kit of a home master. You will need not just a wrench, but a whole arsenal to work with copper pipes and vacuum the system. The main tool will be burner (gas or oxygen-acetylene) and a set for rolling.
Pay special attention to preparing the place: it should be well ventilated, since working with open fire and possible gas leaks requires safety. You will also need a nitrogen cylinder to purge the system, which is a mandatory requirement for modern refrigerators.
☑️ Tools for replacement
Don't forget to prepare consumables: solder (silver or copper-phosphorus), flux, filter-drier and, of course, the refrigerant itself in balloon. The filter drier is always changed whenever the circuit is opened; reusing the old one is unacceptable. Industrial alcohol will be required to flush the system if oil combustion products are found in it.
⚠️ Attention: Work with open fire and flammable materials gases (propane, butane) require compliance with the strictest fire safety measures. Remove all flammable objects from a radius of 2 meters.
Removing the old compressor and preparing the system
The process begins by completely disconnecting the refrigerator from the power supply and moving it away from the wall to provide access to the rear. Remove the rear cover covering the engine compartment and visually inspect the condition of the wiring and pipes. The first step is to cut through the filling tube and capillary in order to bleed off the remaining refrigerant in a safe place.
Next, you should unsolder the suction and discharge tubes from the compressor housing. It is important here not to overheat adjacent elements and not to melt the varnish coating of the windings. Use a damp cloth to cool nearby areas if heat becomes excessive. After disconnecting the tubes, remove the terminals from the start relay and thermal protection.
Unscrew the mounting bolts or nuts holding the compressor to the frame and carefully remove the unit. If rubber damper bushings are used, check their condition: if they are cracked or fossilized, it is better to replace them so that the new motor does not vibrate. Vibration transferred to the housing, causes noise and destruction of the soldering of the tubes in the future.
After dismantling, inspect the condenser (grid at the back) for mechanical damage or corrosion. If fistulas are found, they must be sealed before installing a new compressor. Purge the circuit with nitrogen to remove large fragments of contaminants remaining from the burnt motor.
Installing a new unit and soldering copper pipes
Installing a new compressor is done in the reverse order of dismantling, but with critical additions. First secure the motor to the frame using new dampers, then connect the electrical part. Make sure that the starting relay is installed strictly in accordance with the markings (usually the “UP” arrow points up).
The most critical stage is soldering the tubes. Copper oxidizes when heated, so professionals use nitrogen flushing during soldering. If there is no nitrogen, try to work as quickly and carefully as possible, using a minimum amount of flux. The solder should spread on its own due to the capillary effect, and not spread like plasticine. Be sure to install a new one on the liquid line before entering the capillary tube. It absorbs moisture and acid residues, protecting the system. The direction of flow on the filter is indicated by an arrow, do not confuse the input and output, otherwise the system will not work.
Be sure to install a new one filter-dryer on the liquid line before entering the capillary tube. It absorbs moisture and acid residues, protecting the system. The direction of flow on the filter is indicated by an arrow; do not confuse the inlet and outlet, otherwise the system will not work.
After soldering all connections, it is necessary to carry out pressure testing with nitrogen under a pressure of 15-20 atmospheres. This will reveal leaky seams that could have formed when the metal cooled. If the pressure drops, look for the leak using a soapy solution and resolder the connection.
Evacuating and charging with refrigerant
Evacuating is the process of removing air and moisture from the circuit, which cannot be ignored. Connect the vacuum pump to the process connection and turn it on for at least 30 minutes. The residual pressure should tend to zero, which indicates the removal of water vapor, which, when frozen, can clog the capillary.
Filling with refrigerant is carried out strictly according to the weight indicated on the refrigerator nameplate. Use an electronic tank scale to avoid underfilling or, worse, overfilling. An excess of freon leads to increased pressure and load on the compressor, and a deficiency leads to insufficient cooling.
During the refueling process, the refrigerator must be turned on so that the compressor begins to suck in gas. Monitor the pressure on the low pressure gauge, it should be within the normal range for this type of refrigerant at the current ambient temperature. Temperature in the chamber will also begin to drop, which is an indicator of successful operation.
⚠️ Attention: Refrigerant type R600a (isobutane) is flammable! When working with it, it is strictly forbidden to smoke or use an open flame near the refrigerator while the gas is being vented.
Startup and performance check
After refueling, seal the process pipe and turn on the refrigerator. The first start may be accompanied by a short-term increase in noise, which is normal for a new motor. Check the heating of the compressor: it should heat up evenly, but not to the point where it is impossible to touch it.
Monitor the operation for several hours: the evaporator inside the chamber should be covered with frost evenly, starting from the freon inlet. If the cold appears only at the entrance, and further down the tubes are warm, the capillary tube may be clogged or there is not enough freon. Cyclicity The operation must correspond to the thermostat settings.
Check the tightness of the new connections again after warming up the unit. Thermal expansion of the metal could weaken the solder, so re-checking with a soapy solution would not be superfluous. Make sure that the refrigerator reaches the set temperature and turns off.
Frequent errors and ways to eliminate them
One of the most common mistakes is neglect purging with nitrogen, which leads to rapid failure of the new compressor due to clogging of the system with oxides. Also, craftsmen often forget to change the filter-drier, considering it reusable, which is a gross violation of technology.
Incorrect soldering, when solder flows inside the tube and blocks the flow area, causes a throttling effect and stops the circulation of freon. It is difficult to notice this visually; experience and pressure control are required. Overheating of the tubes during soldering can lead to their burnout and the formation of new holes.
Sometimes the problem lies in the electrics: if the new starting relay is selected incorrectly, the compressor will hum, but not start, or start and immediately stall due to overload. Always check the relay markings with the characteristics of the motor.
What to do if the refrigerator does not freeze after replacement?
Check: 1. The tightness of the circuit (there are no leaks). 2. Compressor operation (is it heating up, is it running). 3. Cleanliness of the capillary (is it purged). 4. The amount of freon. Most often, the problem is poor-quality evacuation or a clogged filter.
Is it possible to replace a compressor without a vacuum pump?
Theoretically, some craftsmen use the method of “squeezing out” the air with freon itself, but this is extremely ineffective and leaves moisture in the system. The moisture will freeze in the capillary and the refrigerator will stop freezing after a couple of days. A vacuum pump is required for high-quality repairs.
How much does it cost to replace a compressor at a service center versus doing it yourself?
In a service center, work costs from 3,000 to 6,000 rubles plus the cost of the compressor. With your own hands, you spend only on spare parts (about 4000-8000 rubles) and tools, if you don’t have them. The savings are significant, but soldering skills are required.
Is it necessary to flush the system if the old compressor burns out?
Yes, if the system contains black oil and combustion products, flushing with industrial alcohol or a special solvent is required. Otherwise, the acid will spread throughout the entire circuit and kill the new motor in a few months.
Which solder is best to use for a refrigerator?
For copper-copper, copper-phosphorus solder (without silver) is ideal, since it does not require flux and has good fluidity. For copper-steel connections (compressor outputs), it is better to use solder containing silver (15-40%) and the appropriate flux.
Why does the new compressor heat up more than the old one?
The new motor may heat up more in the first hours of operation due to the grinding in of parts. Also, the reason may be an excess of freon, air entering the system or insufficient airflow (if the refrigerator is close to the wall).