The situation when the compressor of your refrigerator hums for days on end, and the inside does not get colder, causes understandable anxiety. Continuous operation technicians - this is not only increased electricity bills, but also a direct risk of complete failure of an expensive unit. In systems No Frost the reasons can be hidden both in banal settings and in serious mechanical faults.
Before calling a technician or disassembling the back wall, it is necessary to carry out an initial diagnosis. Often, owners forget that they have turned on some special mode, or simply placed the products incorrectly. Let's figure out why the refrigerator does not turn off and how to determine the source of the problem yourself.
It is worth understanding that modern compressors, especially the inverter type, can operate in constant mode, simply changing the power. However, if you hear characteristic clicks of the relay or the unit operates at full speed without pauses for more than 12 hours, and the temperature on the display does not correspond to the set one, this is a signal of failure.
The influence of external factors and mode settings
The most common cause of panic is the human factor. If you have just returned from the store with a full package of products and loaded them into the chamber, the compressor will work in enhanced mode until it cools the entire volume to the set temperature. This is absolutely normal physics of the heat exchange process.
However, if the food has long cooled down and the motor continues to hum, check the control panel. Many models LG, Samsung or Bosch equipped with the “Super Freeze” or “Express Cooling” function. In this mode, thermostat is forcibly turned off, and the appliance works without stopping.
- ❄️ Check that the fast freezing mode indicator is not on (often indicated by a snowflake or Super button).
- 🌡️ Make sure that the set temperature is not set to the minimum value (for example, +1°C or -24°C).
- 🚪 Inspect the rubber seals: if the door does not fit tightly, warm air constantly flows inside.
Also pay attention to the location of the refrigerator. If it stands close to the wall, in a niche or next to the battery, heat transfer is disrupted. The compressor tries to compensate for the overheating of the condenser by working without interruption. The critical distance is less than 5 cm from the back wall to the nearest surface.
Malfunctions of the thermostat and temperature sensors
If everything is in order with the settings, the problem may lie in the “brains” of the cooling system. The thermostat (or electronic sensor in modern models) is responsible for sending a signal to turn off the compressor when the desired temperature is reached. If this element fails, the controller simply “does not know” that the cold has already been dialed.
In mechanical models, the thermostat is a capillary tube filled with freon. Over time, the tightness can be broken, the gas evaporates, and the contacts simply stop opening. In electronic systems No Frost thermistors are responsible for this. Their resistance can change unpredictably, sending false data to the control board.
Diagnostics of electronic sensors requires a multimeter. It is necessary to “ring” the element at different temperatures. If the resistance readings do not change or go to infinity, the part must be replaced. This is one of the most common reasons why the refrigerator does not turn off.
Problems with the defrost system in No Frost refrigerators
The main difference of the system No Frost is the absence of ice on the internal walls due to forced air circulation and periodic automatic defrosting. If this cycle is disrupted, the evaporator becomes overgrown with ice, blocking airflow. The temperature sensor located in the chamber does not feel the cold and forces the compressor to work constantly.
The defrost chain involves three main elements: a heating element (heater), a timer (or electronic module) and a defrost sensor. Most often, the heating element itself burns out or the sensor fails, which should inform the system that the ice has melted. As a result, the refrigerator “thinks” that there was no defrosting and continues to freeze.
To check the defrosting system, it is often necessary to completely defrost the unit within 24 hours. If after this the equipment worked normally, and a week later the situation repeated itself, the problem is precisely in one of the elements of the defrost system.
- 🔥 Heating element of the heater: checked for the integrity of the spiral (there should be no breakage).
- ⏱️ Defrost timer: a mechanical unit that can get stuck in the cooling mode.
- 📉 Defrost sensor: must open the circuit at a certain temperature (usually +10°C).
Why can't you ignore ice in a No Frost system?
If the evaporator is completely covered with ice, the fan may jam. This will lead to burnout of the fan motor or even breakage of the blades, which will require expensive repairs of the entire air system.
Refrigerant leakage and problems with the compressor
The most unpleasant and costly reason for continuous operation is a freon leak. When the amount of refrigerant in the circuit drops, the pressure decreases and the compressor cannot reach the required temperature to shut down. It works for wear and tear, trying to compensate for the lack of working fluid.
Detecting a leak visually is difficult, since freon is a colorless and odorless gas. Indirect signs are: poor cooling (or its absence when the motor is running), hot side walls (or vice versa, cold if the leak is serious), as well as swelling of the rear wall inside the freezer at the sealing point of the evaporator.
Another option is a malfunction of the compressor itself. If the valves inside the motor are worn out, it does not create the required pressure. In this case the refrigerator is humming, but it does not freeze. Replacing a compressor is a complex procedure that requires evacuation of the system and charging with freon, which cannot be done at home without special equipment.
⚠️ Attention: If you smell a burning smell or hear an uncharacteristic knocking/grinding noise from the motor, immediately unplug the appliance. Further operation may lead to a fire or complete destruction of the compressor.
Comparative table of symptoms and causes
To make it easier for you to navigate possible breakdowns, we have prepared a summary table. It will help narrow down the scope of troubleshooting before the technician’s visit.
| Symptom | Probable cause | Difficulty of repair | Necessity of a technician |
|---|---|---|---|
| It buzzes, but gets cold weak | Freon leak / Capillary clogged | High | Mandatory |
| Does not turn off, there is ice inside | Faulty defrost system (No Frost) | Average | Desirable |
| Works without stopping, there is cold | Thermostat or sensor is faulty | Low/Medium | You can do it yourself |
| Humming, compressor is hot | Compressor wear / Problem with the start relay | High | Mandatory |
Self-diagnosis algorithm
Before calling the service, try to perform a number of simple steps. They will help eliminate false alarms and save time. Start with the simplest thing: checking that the door is tightly closed and that there are no drafts in the room.
Next, perform a complete defrost. Even if you No Frost, leave the refrigerator turned off with the doors open for 24 hours. This will allow ice in hard-to-reach areas to evaporate. If, after switching on, the equipment started working in normal mode (turns on and off), then the problem was in the defrosting system.
☑️ Initial check checklist
If defrosting does not help, a deeper defrost will be required diagnostics using tools. Checking the thermostat and sensors requires care. In some cases, especially with electronic control, it may be necessary to reset errors through a combination of buttons.
⚠️ Attention: Do not attempt to open a sealed circuit or solder tubes yourself unless you are licensed and equipped. This is life-threatening and will permanently damage the equipment.
Frequently asked questions (FAQ)
Can the refrigerator work without stopping in the summer?
Yes, in hot weather (+30°C and above) the load is on the compressor increases. Working time increases and pauses become shorter. However, it should still turn off periodically. If there are no pauses at all, this is a malfunction.
How long should the compressor normally work?
The normal mode is when the compressor works about 30-40% of the total time (coefficient 0.3-0.4). That is, he works for 10 minutes and rests for 20. In fast freezing mode, it can work continuously for up to 12 hours.
Why doesn’t a new refrigerator turn off for a long time?
When turned on for the first time, an empty refrigerator takes time (up to 2-3 hours) to gain temperature. If you loaded it with products immediately, the time may increase to 12-24 hours. This is normal.
Is it dangerous to leave a running refrigerator overnight?
If it is working, no. But if you notice that it has been working non-stop for the second day, leaving it unattended is risky. There may be an overload of the wiring or a fire in the event of an electrical malfunction.