The situation when the refrigerator compartment is warm, but the freezer is working properly, or vice versa - the upper part is functioning, but the lower part has turned into “warm compartment” is familiar to many owners of household appliances. This is a classic symptom of a refrigerant circulation problem or a malfunction in the temperature control system. Refrigerator - this is a closed system, and if an obstruction or leak occurs in one of the sections of the circuit, the temperature balance is upset. In most cases, the problem lies not in a complete breakdown of the unit, but in a specific defect, which can often be diagnosed visually or aurally.
Before calling a technician, it is worth conducting an initial diagnosis. Often the reason the bottom of the refrigerator does not freezeis a banal failure to comply with operating rules or a temporary failure of electronics. However, ignoring the problem can lead to food spoilage and failure of an expensive compressor. It is important to understand the difference between the “thaw” mode and a real malfunction.
In this article we will analyze in detail the mechanical and electrical causes of failures characteristic of different types of equipment. You will learn how to distinguish a clogged capillary tube from a freon leak and why in models No Frost the situation may differ from classic “crying” systems.
The main reasons for the disruption of refrigerant circulation
The most common reason why the bottom of the refrigerator compartment (or freezer, if it is located at the bottom), this is a violation of the permeability of the refrigerant. Freon circulates in the system, which takes heat from the chambers and releases it into the environment. If the path of gas movement is blocked, heat exchange stops. Capillary tube has a very small diameter, so even a microscopic particle of debris or ice can become a fatal obstacle.
Clogging often occurs in the area of the filter-drier. This is where the system goes from high pressure to low pressure, and this is where oil oxidation products or moisture accumulate, turning into an ice plug. If the refrigerator is humming, the compressor is running continuously, but there is no cold, this is a sure sign that freon is not circulating through the circuit.
⚠️ Attention: If you hear gurgling or hissing when the compressor is running, but there is no cold, under no circumstances try to pierce the tubes or disassemble the system yourself. The release of freon in a closed room is dangerous, and moisture getting inside the circuit will make repairs impossible without specialized equipment.
Another option is a refrigerant leak. Metal evaporator tubes, especially in older models or built-in appliances, can corrode. If you notice oily spots on the floor under the refrigerator or on the back wall, this is a signal of depressurization. Freon leak causes the compressor to waste air, trying to gain pressure that is not there.
Problems with defrosting in No Frost systems
In refrigerators with system No Frost the situation when the bottom (freezer) does not work is often associated with a malfunction of the defrost system. Unlike drip models, here the evaporator is hidden behind a plastic panel. If the heating element of the heater, thermostat or defrost timer fails, a “coat” of ice grows on the evaporator.
This ice gradually blocks the channels through which cold air should enter the chambers. As a result, the fan hums, air does not circulate, and the temperature in the freezer begins to rise. Food is defrosting, although the compressor may be operating normally. Diagnostics requires removing the back panel in the freezer compartment.
☑️ Diagnostics of the No Frost system
Often owners confuse this problem with a lack of freon. However, if the air passages are clogged with ice, the compressor may overload. If you defrost the refrigerator manually (by turning it off for 24 hours) and it starts to freeze normally, but after a week the problem returns, it means that one of the elements of the defrosting system is faulty. Defrost timer or the electronic module simply does not give the command to turn on the heater.
To replace elements of the defrosting system it is often necessary to get to the evaporator, which in some models requires partial disassembly of the housing. It is important to check not only the heating element, but also the sensor that controls the temperature of the evaporator. If the sensor is “lying,” the control module may not start the defrost cycle at all. Indesit or Atlant requires partial disassembly of the housing. It is important to check not only the heating element, but also the sensor that controls the temperature of the evaporator. If the sensor is lying, the control module may not start the defrost cycle at all.
Faults in the compressor and start relay
The compressor is the heart of the refrigerator. If it does not start or does not work correctly, there is not enough pressure in the system to circulate effectively. It often happens that the engine hums, clicks, but does not start. This may indicate a jammed piston group or a malfunction of the starting device.
Start relay is a small mechanism responsible for starting the engine. Over time, the contacts in it burn out, or the bimetallic plate loses its properties. As a result, the compressor receives power, tries to start, clicks and is switched off by the protection. In this case, the bottom of the refrigerator stops cooling, since the compression cycle does not begin.
A more serious problem is the interturn short circuit of the motor windings. In this case, the compressor may hum louder than usual and become very hot. If you touch the motor housing (on the bottom rear wall), it can be scalding hot. Replacing the compressor - a complex procedure that requires evacuation of the system and charging with freon, which cannot be done at home without a pump and pressure gauges.
⚠️ Attention: Before When replacing the start relay, be sure to unplug the refrigerator! Working with live electrical components is strictly prohibited. Make sure that the new relay matches the markings of the old one.
Sometimes the problem lies not in the compressor itself, but in its mounting. If the shock absorbers are worn out, vibration is transmitted to the tubes, which can cause them to break off at the base. Visually inspect where the copper tubes exit from the black motor casing. The presence of cracks or traces of oil will indicate mechanical damage.
Failure of the thermostat or control module
Electronics controls all processes in a modern refrigerator. If the thermostat (in mechanical models) or the temperature sensor (in electronic models) transmits incorrect data, the refrigerator may “think” that the chamber is already cold and turn off the compressor. As a result, the bottom stops freezing, although the system is technically working.
In electronically controlled models, such as LG or Samsung, evaporator or air damper temperature sensors often fail. If the sensor shows a temperature lower than the actual one, the module does not turn on the compressor. Diagnostics is carried out with a multimeter: the resistance of the sensor is measured at different temperatures and compared with a table of values.
| Symptom | Probable cause | Check method |
|---|---|---|
| The compressor does not turn on at all | Thermostat or module is faulty | Close the thermostat contacts |
| Buzzing, clicking, does not start | Start relay or compressor | Replacing the relay, checking windings |
| Works constantly, no cold | Freon leak or blockage | Check pressure, look for oil |
| Freezes slightly, cyclically | Sensor faulty or Heating element | Test the defrost system |
It is also worth checking the air damper (damper), if your model has one. It regulates the flow of cold air from the freezer to the refrigerator compartment. If the damper is stuck in the closed position, cold does not enter the upper chamber, and in the lower chamber (freezer) there may be excessive cooling or, conversely, an increase in temperature due to the stop of the overall cycle.
Why do the sensors lie?
Temperature sensors often fail due to oxidation of contacts or aging of the semiconductor element. Over time, their resistance changes nonlinearly, which confuses the controller’s operating algorithms. A visually serviceable sensor can give an error of 10-15 degrees, which is critical for the operation of the refrigerator.
Mechanical damage and operating errors
Often users themselves create the conditions for breakdown. For example, loading hot products into the chamber. This leads to intense evaporation and the formation of a thick ice crust on the evaporator, which the defrosting system cannot cope with. Ice blocks ventilation, and the bottom of the refrigerator stops working effectively.
Another common mistake is installing the refrigerator close to the wall or in a niche without clearance for ventilation. The condenser (grid at the back) must give off heat. If the air exchange is disrupted, the refrigerant does not condense properly, the pressure in the system drops, and performance decreases sharply. Overheating of the compressor Under such conditions, it is only a matter of time.
Mechanical damage may occur during transportation. If the refrigerator was transported lying down and immediately turned on, oil from the compressor could get into the circulation circuit. The oil plug clogs the capillary and the refrigerator stops freezing. In such cases, it is recommended to let the equipment stand unplugged for several hours, but if the oil has already frozen in narrow places, the system will need to be purged with nitrogen.
Self-diagnosis algorithm
To understand why the bottom of your refrigerator does not work, proceed sequentially. First, rule out simple causes: check that the door closes tightly, that the rubber sealing strip is intact, that the ventilation holes are not clogged with food. Then listen to the operation of the unit.
If the compressor is silent, but the light in the chamber is on, the problem is most likely electrical (thermostat, relay, wiring). If the compressor runs non-stop, but there is no cold, look for a leak or blockage. Touch the back of the condenser: it should be warm evenly. If only the top part of the grille is warm and the bottom is cold, this is a sign of a lack of freon.
⚠️ Attention: Technical characteristics and location of components may vary depending on the model and year of manufacture. Always consult the manufacturer's official documentation before disassembling. Some modern models require special software to enter the diagnostic service mode.
A multimeter is often required for accurate diagnostics. Checking the integrity of circuits, winding resistance and sensors allows localization with detail accuracy. However, if you do not have the skills to work with electrical appliances, it is better to limit yourself to external testing and defrosting.
Why did the refrigerator work after defrosting, but after 3 days it stopped again?
This is a classic sign of a malfunction of the defrost system in No Frost models. Ice has again accumulated on the evaporator and blocked the channels. It is necessary to change the heating element, defrost sensor or timer.
Is it possible to add freon yourself?
Absolutely not. For this you need a pressure gauge station, scales and a vacuum pump. In addition, you need to know the type of freon and the exact dosage. Unprofessional refilling will lead to compressor failure.
How much does repair cost if a compressor burns out?
Replacing a compressor is one of the most expensive repairs, often amounting to up to 70% of the cost of a new refrigerator. It is often more economically feasible to buy new equipment, especially if the refrigerator is more than 10 years old.
Does the installation level of the refrigerator affect the operation?
Yes. If the refrigerator is misaligned, the oil may not return to the compressor, causing it to overheat and seize. Use a building level to check the horizontal position.