The situation when you open the door of the refrigerator compartment and feel warmth, while in the freezer the food is “petrified” from the cold, is one of the most common and alarming for the owner of the equipment. Temperature violation in the upper compartment with the bottom working properly often indicates specific malfunctions of the refrigerant circulation system or control. Many users mistakenly believe that since the freezer is functioning, it means that everything is in order with the compressor, but this is not always the case.
Modern units, be they classic models with capillary tube or advanced systems No Frost, have a general cooling scheme, but different principles of cold distribution. Understanding this difference is critical for initial diagnosis. In some cases, the problem is solved by simple defrosting, in others, the intervention of a specialist with a manometric manifold is required.
You should not ignore the first signs of incorrect operation, since long-term storage of products in a warm place will lead to their spoilage, and operation of the equipment in emergency mode can completely destroy the expensive equipment. compressor. In this article we will analyze in detail the mechanical and electrical causes of failure, methods of self-diagnosis and situations when calling a specialist is inevitable.
The fundamental difference in the operation of single-compressor systems
To understand the essence of the problem, it is necessary to briefly consider how cold gets into different chambers. The vast majority of household refrigerators have one compressor that circulates freon in a closed circuit. The first on the path of the refrigerant is always the evaporator of the freezer, since the lowest temperature is required there, often reaching -18°C and lower.
Only after passing through the freezer the refrigerant enters the refrigeration compartment circuit, where the temperature must be maintained at +2...+5°C. If the system works correctly, freon manages to release cold in both compartments. However, if the circulation is disrupted or the tightness is broken, the pressure drops, and there is only enough refrigerant for the first part of the journey - the freezer.
⚠️ Attention: Attempts to “strengthen” the cooling by turning the temperature regulator to the maximum in the presence of a freon leak will lead to overheating of the compressor and its early failure.
There is also a division by type of control. In c mechanical thermostat he models, the sensor is usually located in the refrigerator compartment or in the evaporator area, and it commands the compressor to turn on or off. In systems with electronic control additional electromagnetic valvess may be responsible for the distribution of cold, shutting off the freon supply to one of the chambers.
Refrigerant leakage: the most common cause of the problem
Statistics from service centers are inexorable: more than 60% of cases when the refrigerator stops cooling in the upper compartment are associated with a freon leak. This could be a microscopic hole in the foam circuit (piping around the perimeter of the door to prevent condensation) or in the evaporator. When the amount of gas in the system drops, its pressure is not enough to go through the entire circulation circle.
The gas reaches the evaporator of the freezer, boils there, taking away heat, but simply does not reach the refrigerator compartment in the required volume. In this case, the compressor can work almost without stopping, trying to gain temperature, which is confirmed by the hot side walls of the case. Freon leak It will not go away on its own - the gas is not consumed during operation, it evaporates only through the fistulas.
- 🔍 Visual inspection: Carefully inspect the back wall inside the refrigerator and freezers for blistering paint or oily stains that may indicate a place of corrosion.
- ❄️ Ice analysis: Pay attention to the nature of freezing. If there is no ice crust on the back wall of the refrigerator completely or it is uneven (“shreds”), this is a sure sign of a lack of refrigerant.
- 🔊 Sound accompaniment: Listen to the operation of the unit. Gurgling or hissing sounds when the compressor is running often indicate that a mixture of gas and oil is moving through the pipes due to low pressure.
Accurate diagnostics require professional equipment. The technician connects pressure gauges to the service fitting (usually located at the rear, below) and checks the pressure in the system. If the pressure is below normal or the vacuum does not hold, a leakage is confirmed.
Clogged capillary tube and filter-drier
The second most common reason why the refrigerator is warm and the freezer is cold is a clogged narrow capillary tube. During operation, oil oxidation products, moisture or small debris may enter the system. The filter drier, designed to retain moisture, clogs over time, creating a plug.
The failure mechanism is similar to a leak: the compressor tries to push freon, but encounters resistance. The pressure at the entrance to the capillary increases, and at the outlet it decreases. As a result, the circulation of the refrigerant is disrupted and the cold does not enter the evaporator of the refrigerator compartment. This is often accompanied by overheating of the condenser grille at the rear.
Sometimes the blockage is temporary. Moisture that gets into the system can freeze at the narrowest point of the capillary, forming an ice plug. After a few hours of operation, the plug may thaw and the refrigerator will begin to freeze, but soon the cycle will repeat. This phenomenon is called hydraulic blockage.
⚠️ Attention: It is strictly forbidden to try to clean the capillary tube yourself by pumping air or nitrogen into it under high pressure without proper preparation. This can lead to rupture of tubes or damage to the compressor.
To eliminate the malfunction, the filter-drier must be replaced and the circuit must be purged with nitrogen. In difficult cases, when the blockage is localized deep in the foamed part, technicians have to resolder the system or (in rare cases) use special solvents, although the latter method is considered a temporary solution.
Faults in the No Frost system
In refrigerators with the system No Frost the situation looks different. There is no ice on the back wall, since the evaporator is hidden and cooling occurs due to forced air circulation. If it is warm in the refrigerator compartment and cold in the freezer, the problem often lies in a violation of air circulation or operation of the defrost system defrost systems.
The main failure scenario: the evaporator in the freezer compartment (which is the same for both chambers) is overgrown with ice due to a malfunction of the defrost heating element, timer or sensor defrost. Ice blocks the fan, and cold air simply cannot enter the upper chamber through the air ducts. In this case, it may be cold in the freezer due to the proximity to the cold source, but the refrigerator compartment is defrosted.
- 🌬️ Checking the fan: Open the freezer door and press the button (or magnetic sensor) that simulates the door closing. If the fan does not make noise, it may be frozen or faulty.
- 🧊 Symptom of "ice shell": If you remove the back panel in the freezer, you may find that the evaporator is completely or partially frozen, although this is not visually noticeable from the outside.
- 🔌 Solenoid valve: In two-compressor No Frost systems (rare) or systems with one compressor and valve, the fault may be in the valve itself, which does not switch the freon flows.
Often users notice that after the refrigerator is completely defrosted (for 24 hours with the doors open) it starts working fine. However, after a week or two the problem returns. This is a classic sign of a defrost system malfunction.
☑️ Diagnostics before calling a technician
Problems with the compressor: when the motor “does not pull”
Although the compressor is the “heart” of the refrigerator, its partial malfunction can produce the symptoms described. If the compressor has exhausted its service life, its piston group may wear out. As a result, it loses compression - the ability to create the necessary pressure to pump freon throughout the entire circuit.
The engine hums and starts, but the outlet pressure is too weak. Freon circulates only in a small circle (to the freezer) or does not circulate at all, heating up from the operation of the motor. A breakdown of compressor valvesis also possible, which leads to similar consequences: the unit works, but does not freeze.
Another option is a malfunction of the start-protective relay. It can allow the compressor to start, but immediately turn it off when the current increases, preventing it from reaching operating mode. In this case, you will hear clicking and buzzing sounds lasting several seconds, followed by silence.
| Symptom | Probable cause | The nature of the compressor operation |
|---|---|---|
| Warm at the top, cold at the bottom | Freon leak | Works almost non-stop, hot sides |
| Heat at the top, cold at the bottom | Capillary clogged | Works with overheating, periodicity is possible |
| Heat in both chambers | Broken compressor | Humming and turning off or silent |
| Heat at the top, ice in the freezer | No Frost malfunction | Operating in normal mode |
Diagnostics of the compressor requires measuring current consumption and discharge pressure. If the current is below the rated current and the pressure does not increase, the compressor “does not work” and must be replaced. Repairing an old compressor is not economically feasible.
The role of the thermostat and electronics in temperature control
In older models of refrigerators, the mechanical one is responsible for turning the compressor on and off. thermostat. Its capillary tube is usually attached to the evaporator or in the channel of the fridge compartment.