The situation when the refrigerator seems to be working, the compressor is humming, but the upper chamber has ceased to maintain the desired temperature, is one of the most common complaints from users. Food in the freezer may remain frozen, but milk on the shelves in the main compartment may begin to spoil or ice cream may melt. This is a classic symptom of a refrigerant circulation problem or a malfunction in the temperature control system.
This problem cannot be ignored, as it often indicates a progressive malfunction, which over time can lead to a complete shutdown of the unit or spoilage of the entire food supply. In most cases, the reason lies in the technical part: from a banal blockage to a gas leak. Understanding the principles of operation of your model will help you quickly navigate in finding a breakdown.
Before calling a technician, it is worth conducting an initial diagnosis to eliminate simple factors that do not require complex intervention. Often users panic ahead of time without checking the settings or the tightness of the door. However, if simple methods do not help, we are talking about a serious technical defect.
The operating principle and features of two-chamber systems
To understand why the upper compartment stopped cooling, you need to briefly understand the physics of the process. In classic two-chamber refrigerators with one compressor, the refrigerant (freon) first passes through the evaporator of the freezer, where it boils and takes away heat, and then enters the evaporator of the refrigerator compartment. If at some stage this cycle is interrupted, it is the upper part that suffers, since it is “at the end of the queue.”
In models with the system No Frost cold air is forced by a fan from the freezer into the upper compartment through special channels. If the fan stops or the ducts become frozen with ice, circulation stops. In drip systems (“crying evaporator”), the problem is often associated with direct cooling of the rear wall, which is then transferred to the entire volume.
It is important to consider the age of the equipment. Older models often suffer from design features, while modern ones may display errors on the display indicating a specific component. Understanding the type of cooling system you have is the first step to a decision. Indesit or Atlant often suffer from design features, while modern Samsung or LG may produce errors on the display indicating a specific node. Understanding the type of cooling system you have is the first step to a solution.
Primary diagnostics: what to check before calling a technician
Do not rush to look for the service center number until you rule out the human factor. Sometimes the problem is solved in a couple of minutes. First of all, check that the food is not blocking the ventilation openings. If you have just loaded the shelves tightly, the air may have stopped circulating.
The second important point is the position of the thermostat. Someone in the household could accidentally move a knob or change settings in the electronic menu. Make sure the mode is not set to Minimum or Vacation. Also check the tightness of the sealing rubber around the perimeter of the door: if it allows heat to pass through, the refrigerator will not be able to gain temperature.
⚠️ Attention! If you notice that the compressor is running non-stop (humming around the clock), but there is no cold, immediately unplug the device. Long-term operation in this mode can burn out the motor, and then repairs will cost much more.
The third aspect is defrosting. Even if you have a No Frostsystem, sometimes failures occur and an ice plug blocks the channels. Try defrosting the unit completely (at least 24 hours with the doors open). If after turning on the problem disappeared, then there was a failure in the defrosting system.
☑️ Initial check checklist
Clogged capillary tube: the hidden enemy of the system
One of the most common reasons, The reason why the upper chamber stops freezing is that the capillary tube is clogged. This is a thin pipe through which the refrigerant enters the evaporator. Over time, oil oxidation products, paraffin or moisture can accumulate in the system, which turn into an ice plug inside the tube.
Symptoms of a blockage are very typical: the compressor is working, the condenser (grid at the back) is hot, but there is no cold in the chambers or it is very weak. In this case, the motor may overheat and often turn off via the thermal relay. The pressure in the system drops, and the freon simply does not reach the upper evaporator.
To eliminate this problem, professional intervention is required. The technician must:
- 🛠️ Warm up the capillary tube with a special hairdryer or torch to break through the ice or paraffin plug.
- 🛠️ Purge the system with nitrogen under high pressure to remove debris.
- 🛠️ Replace the filter drier, since the old one will no longer be able to effectively remove moisture.
- 🛠️ Refill the refrigerator with freon and seal the system.
It is almost impossible to remove the blockage yourself without a vacuum pump and a pressure gauge station. Attempts to “break through” the system using homemade methods often lead to rupture of pipes or damage to the compressor.
Why does blockage occur?
Clogging most often occurs due to moisture getting into the system due to poor-quality previous repairs or long-term operation. Moisture freezes at the narrowest point of the capillary, blocking the freon flow. Also, the cause may be the destruction of the motor when oil combustion products clog the tube.
Freon leak: when the gas is gone
If there is no refrigerant left in the refrigerator, cooling becomes impossible. Freon is a working fluid that transfers heat. Modern models use R600a (isobutane) or R134a gases. A leak can occur anywhere in the circuit: in the foamed part of the housing, in the condenser or at the joints of the tubes.
A common cause of leakage in models with a foamed evaporator (the tubes are mounted in the walls of the housing) is metal corrosion. Over time, the metal becomes thinner and gas escapes. Visually, this can be seen by swelling of the side walls or the appearance of rusty spots. In models with a visible evaporator (grid inside), the leak is often visible by oily spots in the soldering areas.
Signs of a freon leak:
- 📉 The compressor works constantly, without turning off, trying to gain temperature.
- 📉 The condenser (rear grill) remains cold or warm only partially.
- 📉 Complete absence of cold in both chambers or weak cold only near the evaporator.
- 📉 A characteristic whistle or hissing when turned on (if the leak is large).
Repair in the event of a leak in the foamed part is difficult and expensive. Often, experts suggest installing an external evaporator (“crying” circuit) inside the chamber, since opening the factory foam and changing the foamed evaporator is not economically feasible.
Malfunctions of the thermostat and temperature sensors
Electronics and mechanics of temperature control are another layer of problems. If the “brain” of the refrigerator receives incorrect data, it will not give the command to cool. In mechanical models, a thermostat is responsible for this; in electronic models, air sensors and the main control module are responsible.
The thermostat is a simple switch that opens the circuit when the desired temperature is reached. If its contacts are stuck or the bellows has lost its seal, the circuit may not close at all and the compressor simply will not start. Or, on the contrary, it will work without interruption, but incorrectly.
In electronic systems Samsung, Bosch or LG a separate sensor is responsible for the temperature in the upper compartment. If it “lies” (shows that there is enough cold, although it is warm there), the compressor will not turn on. Often such errors are recorded in memory and displayed as codes on the display.
To check the thermostat in mechanical models, you can close its contacts directly. If the refrigerator is working, the reason is in the thermostat. For electronic sensors, you need a multimeter to measure resistance at different temperatures.
Problems with the defrost system (for No Frost)
In refrigerators No Frost the upper compartment does not cool if the evaporator in the freezer is frozen. Ice blocks the fan and damper, and cold air simply cannot get up. The defrosting system consists of a heating element, a timer (or electronic module) and a thermal fuse.
If the heating element of the heater burns out, the ice does not melt and increases with each cycle. If the defrost timer is faulty, it will not switch the refrigerator to defrost mode. As a result, you get a block of ice behind the back wall of the freezer and heat in the refrigerator compartment.
Diagnostics requires disassembling the freezer and removing the back panel. It is necessary to “ring” the heating element for integrity and check the resistance of the thermal fuse. Often it is the fuse that fails, which costs a penny, but without it the circuit does not work.
| Component | Failure symptom | Check method | Difficulty of repair |
|---|---|---|---|
| Defrost heating element | Ice on the evaporator, no defrosting | Resistance measurement (should be normal) | Average (needs disassembly) |
| Timer/Module | The refrigerator does not go into defrost or does not come out of it | Checking the voltage on the contacts | High (electronics) |
| Fan | Noise, lack of air circulation | Visual inspection of blade rotation | Low (unit replacement) |
| Damper | Freezes or does not let in cold | Checking the mechanics and damper drive | Medium |
⚠️ Attention! Information about error codes and sensor locations may vary depending on the specific series and year of your model. Always check the manufacturer's technical documentation before starting disassembly.
Rare but possible causes
Sometimes the problem lies where you don't expect it. For example, a malfunction of the compressor motor. If the compressor's performance has decreased (valve group wear), it may hum, create vibration, but not build up enough pressure to pump freon through the entire circuit. As a result, the freezer still somehow keeps minus, and the top is “warm.”
Another reason is the loss of the seal of the case. If you often leave the door open or the seal is very worn, a lot of moist air enters the chamber. The defrosting system does not have time to remove moisture, and the “ice collapse” described above occurs.
In refrigerators with a freshness zone (zero chamber), the damper or fan responsible for this particular compartment may separately fail. In this case, the rest of the refrigerator operates normally, and the freshness zone turns into an ordinary shelf.
Frequently asked questions (FAQ)
Is it possible to operate the refrigerator if the upper chamber does not freeze?
Short-term - yes, if the food does not spoil. Long-term operation is harmful to the compressor, which will wear out, trying to compensate for the lack of cold. This can lead to its combustion.
How much does repair cost if the problem is a freon leak?
The cost depends on the difficulty of accessing the leak. If the tube is visible, the repair is inexpensive. If there is a leak in the foamed part of the body, the price will increase due to the complexity of the work or installation of a new evaporator.
Why, after defrosting, did the refrigerator stop freezing again after a week?
This is a sure sign of a malfunction of the defrosting system (heating element, timer, sensor) in the models No Frost. Ice accumulated again and blocked the channels. The burnt element needs to be replaced.
How can you tell that the capillary is clogged and the freon has not left?
When clogged, the compressor is often hotter than usual, it can operate jerkily, and the condenser heats up unevenly. If there is a leak, the condenser is usually cold, and the motor may be warm, but operates constantly without a characteristic pressure.
Is it necessary to change the compressor if it has been idling for a long time?
Not necessarily. If the compressor starts and creates pressure (checked by the technician), it can be left. But if it overheats and jams, replacement is inevitable.