The situation when in the refrigerator Samsung s system No Frost the upper chamber suddenly stops freezing, which is one of the most common and unpleasant problems for owners. Products in the freezer compartment may remain frozen, while in the main chamber the temperature rises to critical values, which threatens the spoilage of stocks. Often users notice an ice “coat” on the back wall or, conversely, complete dryness in the absence of cold.
The reason lies in the disruption of the circulation of cold air, which is produced in the freezer and must be forced upward. In systems No Frost a complex system of fans, dampers and sensors is responsible for this process. If any element of this chain fails, the physics of the process is disrupted, and the cold stops flowing into the refrigeration compartment.
Before calling a technician, it is necessary to carry out an initial diagnosis, since in many cases the problem can be solved independently or the faulty unit can be pinpointed. It is important to understand that ignoring the symptoms can lead to failure of the compressor, the repair of which will cost much more than replacing the thermal fuse or sensor.
Symptoms of defrosting system malfunction
The first sign that the refrigerator Samsung has stopped functioning normally is often not the lack of cold, but extraneous sounds or visual changes. The system No Frost implies the absence of ice inside the chambers, so the appearance of frost on the products or walls is a direct signal of a failure.
Pay attention to the operation of the compressor. If it hums almost continuously, trying to gain temperature, but there is no desired effect, it means that the cooling capacity is impaired. Also an alarm bell is a hot side wall of the case during normal motor operation.
⚠️ Attention: If you notice that the back wall in the refrigerator compartment is covered with a thick layer of ice or, conversely, has become completely dry and warm when the compressor is running, immediately stop loading new products and defrost.
The automatic diagnostic system often records errors that can be displayed by blinking indicators on the control panel. For example, flashing temperature symbols may indicate a specific failure in the sensor circuit.
Impaired air circulation: fan and damper
The operation No Frost is based on the principle of forced convection. Cold air is generated around the evaporator, hidden behind a plastic panel in the freezer, and blown by a fan into the upper compartment. If this process is stopped, the upper chamber turns into a regular cabinet.
Most often the problem lies in freezing of the air supply channel. A snow “plug” blocks the flow, and the fan, even working properly, cannot blow air through the ice jam. This occurs due to abnormal operation of the evaporator defrost system.
- ❄️ Check whether the sound of the fan running is heard when the freezer door is open (you need to press the door simulator button).
- 🌬️ Inspect the air ducts for the presence of ice plugs, which often form at the junction cameras.
- 🔧 Make sure that the temperature regulator damper is not stuck in the closed position.
If the fan hums but does not spin, it may be jammed with ice or the bearing has failed. In models Samsung with digital control, the position of the damper is regulated electronically, and a failure in its operation also leads to a lack of cold from above.
How to check the fan without disassembling?
Apply a strip of thin paper to the air duct openings in the refrigerator compartment. If the fan is running and there is no ice, the paper should be noticeably attracted by the air flow.
Problems with the defrost heating element and thermal fuse
The most likely reason why Samsung refrigerator it does not freeze in the upper chamber is a malfunction of the evaporator defrost system. Ice builds up on the radiator, blocks the channels, and cold stops flowing into the refrigerator compartment. The key elements here are the heating element (heating element) and the thermal fuse.
The thermal fuse is a disposable protective element that breaks the power supply circuit of the heating element during critical overheating. If it burns out, the heater stops turning on, the ice does not melt and gradually blocks the entire system. You can check it with a multimeter in continuity mode: a serviceable fuse shows zero, a burnt fuse indicates a break.
The defrost heating element itself can also burn out or become covered with a layer of scale, which reduces efficiency. Some models Samsung use a heating element built into an aluminum profile, which is more difficult to diagnose visually, but can easily be checked for resistance.
☑️ Diagnosis of the defrost system
⚠️ Attention: Replacing the thermal fuse without eliminating the cause of its burnout (for example, sticking of the defrost relay on the board) will lead to repeated failure after a short period of time.
Temperature sensors and their effect on operation
Modern refrigerators Samsung are equipped with several temperature sensors that control the operation of the compressor and defrost system. If the evaporator sensor “lies” and shows that the temperature is high, the controller may not start the defrost mode, which will lead to ice accumulation.
The air sensor in the refrigerator compartment also plays an important role. If it malfunctions, the control board may “think” that the cold has already been dialed in and turn off the refrigerant supply or the fan. The resistance of the sensors changes depending on the temperature, and a deviation from the nominal value of even 10-20% can cause the algorithm to fail.
Often users are faced with a situation where after replacing the sensor the problem does not go away. This may indicate oxidation of the contacts in the connector or a malfunction of the control board itself, which does not read the readings correctly.
| Element | Function | Failure symptom | Check method |
|---|---|---|---|
| Defrost heating element | Evaporator heating | Ice block in the freezer | Resistance measurement |
| Thermal fuse | Overheat protection | The heating element does not turn on | Open circuit test |
| Evaporator sensor | Temperature control | No defrost or short | Resistance measurement |
| Fan | Air circulation | Heat in the upper chamber | Visual and sound |
Freon leak: a hidden threat
If the defrost system is working properly, the fan is spinning, but the cold still does not reach the upper chamber, there is a possibility of a refrigerant leak. In refrigerators No Frost the evaporator is often baked into polyurethane foam or hidden behind a plastic panel, which makes visual search for a leak impossible.
When there is a partial leak of freon, the compressor works constantly, trying to compensate for the lack of pressure. The circuit in the freezer is usually the first to freeze, and the freon simply does not reach the refrigerator compartment in the required state of aggregation. A characteristic sign is a hot condenser (grid at the back) with poor cooling inside.
In such cases, you need to call a specialist with a leak detector and equipment for evacuation and refilling. It is almost impossible to independently repair a leak in the foamed part of the case without compromising the integrity of the thermal insulation.
Failures in the operation of the control board
The “brain” of the refrigerator Samsung is an electronic module that controls all processes. Voltage surges in the network can lead to burnout of triacs that control the defrost heating element or the compressor relay. In this case, physically serviceable parts do not receive a command to turn on.
A frequent problem is the defrost relay contacts sticking in the “open” position. The board “sees” working sensors, but does not supply voltage to the heater. Diagnostics requires opening the module and checking the output voltages in defrost mode.
Sometimes the problem is solved by flashing or resetting the error (“glitch”) of the electronics. To do this, the refrigerator is disconnected from the network for a long time (more than 30 minutes), which allows the capacitors to discharge and the controller memory to clear.
⚠️ Attention: Repairing the electronic board requires qualifications. Improper replacement of components can lead to a short circuit and complete failure of the refrigerator.
Self-defrosting algorithm
Before buying spare parts, it is necessary to exclude simple freezing. Complete defrosting is the first and mandatory diagnostic step. It allows you to melt ice plugs in the channels and check whether the system will start in normal mode.
To properly defrost the refrigerator Samsung you need to unplug it, completely empty it of food and leave it with the doors open for at least 24 hours. A shorter procedure may not melt the ice deep in the channels and on the hidden evaporator.
After defrosting, turn on the device empty. If within 24 hours the temperature in the upper chamber has not dropped to normal, and frost or ice has appeared on the back wall again, the problem is of a technical nature and requires replacement of parts.
Frequently asked questions (FAQ)
Why, after defrosting, did the Samsung refrigerator stop freezing again after a week?
This is a classic sign of a malfunction of the defrost system. Ice has again accumulated on the evaporator and is blocking the air passages. Most likely, the heating element, thermal fuse or defrost sensor has failed.
Is it possible to operate the refrigerator if the upper chamber does not freeze?
Short-term - yes, but you cannot work in this mode for a long time. The compressor will work hard, trying to gain temperature, which will lead to overheating and expensive repairs. In addition, the food in the upper chamber will spoil.
How much does it cost to replace a defrost heating element in a Samsung refrigerator?
The cost consists of the price of the spare part and the work of the technician. The heating element itself is relatively inexpensive, but replacing it requires complete disassembly of the freezer, which is labor-intensive. It is better to check the exact price at service centers in your region.
Does the fan hum when the No Frost system malfunctions?
Not always. The fan may hum normally, but air will not flow through the ice plug. Or it may be blocked by ice and humming without rotating. The absence of a fan sound when the freezer door is open also indicates its malfunction.