After carrying out a complex and expensive procedure for replacing compressor in the refrigerator, owners are often faced with an incomprehensible situation: the unit hums, but the cold does not appear for several hours. This causes panic and fears that the repair was performed poorly or the new part is faulty. However, you should not rush to conclusions and call the technician at this moment, since the process of stabilizing the system takes time.
The time required to reach operating temperatures directly depends on the type of refrigerant, chamber volume and environmental conditions. On average, a full cooling cycle takes from 2 to 24 hours, but there are nuances that can significantly increase this period. Understanding the physical processes occurring inside refrigeration circuitwill help you objectively assess the condition of the equipment and avoid unnecessary stress.
In this article we will look in detail at why a refrigerator may not freeze for a long time, what factors affect the cooling rate and when it is really necessary to sound the alarm. We will look at the technical features of the operation of new compressors and heat removal systemsso that you can be confident in the serviceability of your equipment after service intervention.
Factors affecting the cooling rate
The first thing to consider is the type of refrigerant that was used uploaded to the system. Modern models often work on R600a (isobutane)which has excellent refrigeration characteristics, but requires more precise dosing and vacuuming. Old models used R134a or freon, and the time they reach the operating mode may differ significantly due to different heat capacity and pressure in the circuit.
The second critical factor is the air temperature in the room. If the repair was carried out in a hot workshop or kitchen, where the temperature exceeds +25°C, the refrigerator will require much more time to remove heat through the condenser. In such conditions, heat transfer is difficult, and the compressor is forced to work at the limit of its capabilities longer than usual.
The volume of the refrigeration chamber and the degree of its loading also play an important role. An empty refrigerator cools down faster because it only needs to cool the air and the walls. If you immediately loaded the chambers with products, the time to enter the mode may increase by one and a half to two times, since the heat capacity of the products is high.
⚠️ Attention: If in the room where the refrigerator is located, the temperature is below +10°C or above +35°C, the cooling process may not begin at all or proceed extremely slowly due to the activation of protective mechanisms or physical limitations of the refrigerant.
Do not forget about the condition of the capacitor. If, after replacing the compressor, the radiator grille was poorly cleaned of dust or moved too close to the wall, the efficiency of heat removal decreases. This leads to the fact that freon does not have time to condense into liquid before entering the evaporator, and the cold is not produced in the required volume.
Standard operating time before the first shutdown
Many users mistakenly believe that the refrigerator should periodically turn off immediately after turning on. However, after replacing the compressor and refilling with freon, the unit can operate without stopping for up to 24 hours. This is a normal operating mode necessary to dry the system from moisture and reach deep minus in the evaporator.
In the first hours of operation, the compressor creates the necessary pressure for the circulation of the refrigerant. During this period thermostat or the electronic control module “sees” that the temperature in the chamber is still far from the set one, and does not give a command to stop the engine. Interrupting this process may lead to incorrect operation of the system in the future.
Continuous operation time also depends on the algorithms of a particular manufacturer. For example, equipment Liebherr or Bosch may have an extended first cycle for calibrating sensors, while simple models Indesit or Atlant reach the mode faster, but their operating cycle is shorter.
If your refrigerator has worked for more than 24 hours without a break and the temperature in the cells has still not dropped below +10°C, this is a cause for concern. Most likely, there is a freon leak, a clogged capillary tube, or an error when installing a new compressor.
Differences in the behavior of different types of refrigerators
The behavior of the refrigerator after replacing the compressor greatly depends on its design features. It is important for owners to understand the difference between systems No Frost and drip models, since their cooling algorithms are fundamentally different.
In systems No Frost cold is produced in a separate evaporator, hidden behind a plastic panel, and is distributed throughout the chambers by a fan. Here it is important not only to cool the air, but also to warm up the defrost heating element to make sure the cycle is working properly. Therefore, the first cycle may be longer, and the noise of the fan may be distracting, creating a false impression of active operation.
Drip refrigerators (crying type) are cooled directly through the back wall of the main chamber. Here the process is visualized: you immediately see how a “snow coat” or drops appear on the back wall. In the freezer compartment, cold appears a little later, since the refrigerant first passes through the main evaporator.
| System type | Time to first cold | Time to complete freezing | Features |
|---|---|---|---|
| Drip (Static) | 30-60 minutes | 4-8 hours | Cold comes from the back wall |
| No Frost (Ventilated) | 1-2 hours | 8-12 hours | Uniform distribution, fan noise |
| Combined | 1-2 hours | 10-14 hours | Different modes for the upper and lower compartment |
| Two-compressor | 30-40 minutes | 4-6 hours | Independent operation of circuits |
Two-compressor models, where separate motors operate for the refrigeration and freezer compartments, usually reach the operating mode faster. If one of the compressors has been replaced, the second may continue to operate normally, which sometimes confuses the user who expects the entire system to operate synchronously.
Signs of proper operation after replacement
How to understand that the new compressor is working correctly? First of all, pay attention to the uniform heating of the capacitor grid (usually located on the back or sides of the case). It should be warm or hot over the entire area, which indicates proper circulation refrigerant.
The second sign is the appearance of cold. A noticeable temperature difference should be felt in the refrigerator compartment after 2-3 hours. In the freezer, after 4-6 hours the water in the glass should begin to freeze if you use it for testing. This is a basic test that is available to everyone.
The sound of a running compressor is also an indicator. It should be smooth, monotonous, without sharp knocks, clicks or gurgles. Although slight gurgling in the first hours after charging with freon is allowed (this circulates oil and gas), extraneous mechanical sounds are unacceptable.
⚠️ Attention: If the new compressor heats up to a temperature above 80-90°C (the hand does not tolerate touching for more than 2 seconds), this may indicate overheating due to improper charging of freon or problems with electrical part.
It is also worth checking the absence of vibrations in the housing. A new compressor installed by a professional should not cause the pipes to rattle or shake the entire unit. If you feel strong vibration, the mounting geometry or pipe resonance may be broken.
Why do the side walls get hot?
After replacing the compressor, the side walls of the refrigerator can become very hot. This is normal, since many models have circuit tubes built into the housing to prevent condensation. Intense heating in the first day indicates active operation of the system.
Typical installation errors and their impact
Unfortunately, the human factor plays an important role when replacing a compressor. One of the most common mistakes is insufficient evacuation of the system. If there is air or moisture left in the circuit, this leads to the formation of ice plugs in the capillary tube, which blocks the circulation of freon.
The second common mistake is incorrect refilling of the refrigerant. Excess freon causes liquid refrigerant to enter the compressor, causing it to knock and quickly wear out. The lack of freon does not allow the required pressure to be built up, and the refrigerator simply does not freeze, running in vain.
Using the wrong compressor or oil also has a fatal effect on service life. For example, replacing mineral oil with synthetic oil (or vice versa) without completely flushing the system leads to clotting of the oil and clogging of the filter drier. As a result, the system stops working after a few hours or days.
- ❌ Insufficient vacuuming time (less than 20-30 minutes).
- ❌ Using an open system when soldering, which lets moisture in.
- ❌ Incorrect selection of compressor power relative to volume evaporator.
- ❌ Ignoring the replacement of the filter-drier, which must be changed whenever the circuit is opened.
If the technician ignored the replacement of the filter-drier, the moisture that entered the system during the repair will, after some time, cause corrosion of the internal parts and blockage of the capillary. This is a classic error that will not appear immediately, but after several weeks of operation.
☑️ Check after replacing the compressor
When it is necessary to contact the technician again
There is a clear time interval after which the wait loses its meaning. If more than 24 hours have passed, and the temperature in the refrigerator compartment is above +10°C, and in the freezer compartment is above -5°C, it is necessary to call a specialist for re-diagnosis.
An alarming signal is also the situation when the compressor operates silently (barely audible) and remains cold, although it should warm up. This is a sure sign that freon is not circulating - either it is not there (leakage) or the system is clogged. You should also be wary if the compressor turns on for 1-2 minutes and turns off before it has time to start.
The appearance of frost in only one place (for example, at the entrance to the evaporator or on the filter) in the absence of cold in the chamber indicates a clogged system. In normal mode, frost or condensate should be distributed evenly over the surface of the evaporator.
⚠️ Attention: Do not try to open the circuit yourself or add freon “by eye”. This requires special equipment (pressure gauge station, scales, vacuum cleaner) and qualifications. Independent actions will lead to the final breakdown of the equipment.
If you notice oil under the refrigerator or on the compressor tubes, this indicates a violation of the solder tightness. In this case, operation of the device is prohibited, since an oil leak will cause the motor to jam within several days.
Recommendations for operation on the first day
After replacing the compressor, it is important to ensure gentle operation of the equipment. Do not load the refrigerator with food in the first 6-8 hours. Let the unit run idle so that it stabilizes the temperature and returns to normal operating parameters.
Ensure good ventilation around the refrigerator. Do not move it close to the wall, leave a gap of at least 10-15 cm for free air circulation. This will help the condenser release heat more efficiently, especially during the period of intense operation after repair.
Do not change the thermostat settings in the first day. Leave them in the middle position (usually 3 out of 5 or mode Eco). A sudden setting to maximum will create excess load on the new compressor during the break-in period.
Frequently asked questions (FAQ)
Is it possible to plug in the refrigerator immediately after delivery and replacement of the compressor?
Yes, if transport was carried out in a vertical position. If the refrigerator was lying during transportation, it is necessary to let it stand for at least 2-4 hours (or better yet, a day) before turning it on, so that the oil flows into the compressor crankcase.
Why does the refrigerator hum loudly after replacing the compressor?
The new compressor may work louder than the old one, since the parts have not yet gotten used to it. However, a strong hum, rattling or knocking indicates improper mounting, pipes touching the housing, or a defect in the motor itself. If the noise does not subside after a day, a technician needs to check it.
How many times per hour should the refrigerator turn on and off after repair?
On the first day, the cycles can be long (work 40-50 minutes, rest 10-15 minutes). A mode where the operating time is about 70-80% of the total time is considered normal. Frequent switching on (every 5 minutes) indicates a problem with the thermostat or a freon leak.
Is it necessary to defrost the refrigerator after replacing the compressor?
There is no need to specially defrost it if the No Frost system is working properly. However, if moisture gets into the system during the repair process, it may freeze out as ice during the first cycle. If after a day you see a lot of ice, this is a sign of poor-quality vacuuming.
What kind of warranty is enough to require for replacing a compressor?
The standard warranty for work on replacing a compressor and refilling with freon is from 6 to 12 months. For the compressor itself, the manufacturer's warranty can reach 3-5 years, but it is important that the technician issues a certificate of completion of work indicating the date and serial number of the part.