The situation when the refrigerator No Frost is turned on, the compressor is humming, the light inside is on, but the food begins to deteriorate due to the lack of cold, is one of the most common and alarming for owners of household appliances. Unlike drip systems, where signs of malfunction may appear in the form of puddles on the floor, the system No Frost often hides the problem until the last moment, when the temperature in the chambers has already risen above critical. Understanding that the unit “works” (makes sounds, vibrates) does not mean that it performs its main function - cooling.
In most cases, the root of all evil lies in the disruption of refrigerant circulation or failures in the electronics that control the defrost cycles. The user may hear the usual hum of the motor, thinking that the system is functioning normally, but it may be warm inside the freezer. It is important not to ignore the first signals, such as a long time of operation of the compressor without interruptions or the appearance of ice in unexpected places, even if outwardly the unit appears to be in good order. The critical sign is the temperature difference: if it is warm in the refrigerator compartment and still cold in the freezer (or vice versa), this narrows the scope of troubleshooting.
Further actions of the owner depend on an accurate diagnosis of the symptoms. Do-it-yourself repairs are possible in cases of capillary tube blockage or sensor failure, but a refrigerant leak or compressor failure often requires the intervention of a licensed professional. Below we will analyze in detail the main components of the system No Frostthat can cause a lack of cold, and we will propose an action algorithm for each case.
Problems with refrigerant circulation: leakage and blockage
One of the most common reasons why the refrigerator No Frost stopped freezing is a banal freon leak. The refrigerant circulates in a closed circuit, and if a microcrack appears in the system (often due to corrosion or mechanical damage during defrosting), the gas escapes. At the same time, the compressor continues to work, trying to pump what is not in the system, which leads to its overheating and lack of cold. Visually, this can be seen by swelling of the side walls or the appearance of rusty spots in the places where the tubes are soldered.
The second option for circulation problems is clogged capillary tube. An ice or dirt plug may form in the system, which blocks the flow of freon. The symptoms are often similar to a leak: the compressor runs almost non-stop, trying to overcome resistance, but there is no cold. Sometimes you can hear a characteristic gurgling or whistling sound coming from the back of the unit, which indicates gas passing through a narrow orifice at high pressure.
Diagnosing these problems requires specialized equipment, such as a leak detector and a gauge manifold. It is almost impossible and even dangerous to independently determine the location of the leak or break through the blockage without skills and tools. If you notice that the condenser grille at the back remains cold when the motor is running, the likelihood of a leak or blockage is more than 80%.
Malfunctions of the defrost and timer system
The system No Frost implies periodic activation of the heating element to defrost the evaporator. If this process is disrupted, the evaporator becomes overgrown with a “coat” of ice, which tightly blocks the ventilation ducts. Air simply cannot circulate between the chambers, and the cold does not enter the main compartment. The main culprit here is often defrost timer or the electronic control module.
If the timer is stuck in the “cooling” mode, the heater will never turn on, and the ice will build up until it completely blocks the air path. If the timer is stuck in the “defrost” mode, the compressor will not start and the refrigerator will simply stop freezing, although the light will be on. Also, defrost sensors often fail, they incorrectly read the temperature and do not give a command to turn on the heating element.
To check this group of faults, it is often necessary to completely defrost the refrigerator for 10-12 hours. If, after defrosting, the unit begins to freeze normally for a day or two, and then stops again, the problem is guaranteed to lie in the defrosting system components. This is a classic symptom that cannot be ignored.
Failure of the evaporator fan
Unlike old models, where the cold went down on its own, in No Frost the fan is responsible for forced air circulation. If it stops, cold air remains in the freezer compartment (or behind the wall) without entering the refrigerator compartment. As a result, food may freeze in the freezer, and melt in the upper compartment, or the cold will not be felt anywhere if the sensor quickly turns off the compressor.
The reasons for the fan stopping can be different: from the banal freezing of the blades due to frozen ice to the failure of the electric motor or broken wiring. Often a problem is indicated by the absence of a characteristic wind noise when the freezer door is open (provided that the door sensor is working properly). The fan may also hum, crackle, or operate intermittently, which indicates wear of the bearings.
You can check the operation of the fan by opening the freezer door and holding the door open sensor (usually located at the end), simulating closing. If you do not hear the noise of a running fan after 1-2 minutes, then the problem is in it or in its power supply circuit. Sometimes it is enough to simply defrost the unit so that the blades begin to rotate freely again.
Why can a fan freeze?
If the door seal does not fit tightly, moist air enters the chamber. It settles on the evaporator and, when frozen, can block the rotation of the fan blades, which are located in close proximity.
Failures in the operation of the thermostat and sensors
The electronics of the refrigerator No Frost relies on the readings of many sensors. If thermostat (or the electronic temperature sensor) transmits incorrect data that the chamber is already cold enough, it will not give the command to the compressor to turn on. As a result, the refrigerator is turned off, the light is on, but there is no cold. This is a common problem in models with mechanical control, where the thermostat loses calibration over time.
In modern models with electronic control, temperature sensors (NTC thermistors) are responsible for everything. Their resistance changes depending on the temperature, and if the sensor “lies” or breaks, the control module can block the start of the compressor to avoid emergency situations. Often a breakdown is accompanied by blinking indicators on the control panel or the appearance of an error code.
Diagnostics of sensors is carried out with a multimeter by testing and measuring resistance at different temperatures. Replacing the thermostat in mechanical models is a relatively simple procedure and is often performed by the owners themselves. However, replacing electronic sensors requires disassembling the internal casing and knowledge in the field of electronics.
| Symptom | Possible cause | Action |
|---|---|---|
| The compressor does not turn on, the light is on | Faulty thermostat or start relay | Replacing the thermostat or relay |
| The compressor hums, but does not start | The compressor is jammed or the starter is burned out | Call a technician, replace the starter |
| The refrigerator works without stopping | Freon leak or blockage | Searching for leaks, refueling |
| It’s cold in the freezer, it’s warm in the refrigerator compartment | The fan does not work or the duct is frozen | Defrosting, checking the fan |
Faults of the compressor and start relay
Compressor - This is the heart of the refrigerator, and if it fails, the system stops working completely. However, it often happens that the motor itself is intact, but cannot start due to a malfunction start relay or protective thermal contact. In this case, you may hear a short click, a hum for a few seconds, and then a shutdown click again. This is a sign that the compressor is trying to start, but cannot gain speed.
If the compressor runs constantly without turning off, but does not create the necessary pressure (does not freeze), this may indicate a loss of compression inside the cylinders. The valves could be worn out or burned out, and the gas is simply rushing around in circles without compression. Such a breakdown requires replacement of the compressor, since the unit cannot be repaired.
It is important to distinguish between a noisy compressor and abnormal sounds. A knocking, clanging, or intermittent humming sound is a sure sign of mechanical failure. In such cases, operation of the refrigerator must be stopped immediately to prevent complete burnout of the motor windings.
☑️ Primary diagnostics of the compressor
Operation rules and prevention
Often reasons why refrigerator No Frost stops freezing, the problem lies not in the breakdown of parts, but in improper operation. Loading hot food, not closing the door tightly or damaging the seal leads to a constant influx of moisture. This moisture freezes on the evaporator faster than the defrost system works, and eventually blocks the system.
It is also important to keep the condenser grill at the back of the refrigerator clean. If it is clogged with dust and animal hair, heat transfer is impaired. The compressor overheats and may be switched off by protection, or the cooling efficiency drops to zero. Regular cleaning behind the refrigerator is a simple but effective preventative measure.
You should not ignore installation requirements. If the refrigerator is too close to the wall or in a niche without gaps, air circulation around the cabinet is disrupted. This is especially critical for built-in models, where ventilation is provided for by the furniture design. Failure to comply with these standards leads to system overload and premature failure.
⚠️ Attention: If you smell burning or see sparking in the compressor area, immediately unplug the refrigerator. Further activation may result in a fire.
⚠️ Attention: Technical characteristics and location of components may vary depending on the specific model and year of manufacture. Always check the manufacturer's official instructions before starting disassembly.
Frequently asked questions (FAQ)
Is it possible to use a refrigerator if it does not freeze, but works?
Use such a refrigerator for Storage of perishable products is strictly prohibited. The temperature in the chambers rises above the safe norm (+5...+8°C), which creates an ideal environment for the growth of bacteria. Products can deteriorate in a few hours, even if it is not yet noticeable outwardly.
How long should complete defrosting take to check?
To effectively remove the ice plug in the system No Frost the refrigerator must stand unplugged from the mains with the doors open for at least 10-12 hours. A shorter defrosting may not melt the ice in hidden channels and ventilation holes.
Why did the refrigerator start to freeze after defrosting, but then stopped again a day later?
This is a classic sign of a defrosting system malfunction (the heating element, timer or sensor burned out). The ice melted, air began to flow, but during the next cycle of operation the system froze again and blocked the channels. A faulty element of the defrost system needs to be replaced.
Is it dangerous to change freon in the refrigerator yourself?
Yes, it is dangerous and ineffective without equipment. Freon requires evacuation of the system before refueling and precise dosage. In addition, modern refrigerants can be a fire hazard when mixed with air. Refilling should only be carried out by a certified technician.