The situation when you open the refrigerator door, you see a light on, but there is warmth inside, and the food begins to deteriorate, causes panic in any home cook. This is a classic sign that electrical circuit it is intact, but the cooling system has failed. The light in the chamber lights up from a separate circuit, which does not depend on the operation of the motor-compressor, so its glow is only an indicator of the presence of voltage in the network, but not a guarantee of the unit’s serviceability.
The first thing to do at such a moment is to listen. Does compressorwork? Does it make the usual hum or vibrate when you put your hand on it? It often happens that the engine either does not start at all, or runs nonstop, trying to gain temperature, but to no avail. Understanding how how exactly the unit behaves in the first minutes after opening the door will help narrow the range of possible faults and save time on diagnostics.
You should not immediately call a technician or take the equipment to a service center without conducting an initial inspection. In some cases, the problem lies in trivial things that you can fix yourself in a few minutes. However, when it comes to refrigerant leaks or electronic failures, professional attention will be required. Let's look at the main scenarios why your refrigerator stopped performing its main function.
⚠️ Attention: If you smell a strong burning smell or see sparking in the compressor area, immediately unplug the appliance. Further operation may lead to a fire.
Problems with the thermostat and temperature sensors
One of the most common reasons why the refrigerator stops freezing is failure of thermostat (thermostat). This element is responsible for turning the compressor on and off depending on the temperature inside the chambers. If the thermostat contacts have oxidized or the mechanism is stuck in the "off" position, the signal to start the engine simply does not arrive, although the light in the chamber continues to burn.
In modern models with a system No Frost and electronic control, instead of a mechanical thermostat, they can be used temperature sensors (thermistors). Their readings are read by the control module, which makes the decision to start the compressor. If the sensor “lies” and shows that it is already cold in the chamber, the compressor will not turn on. You can check a mechanical thermostat by closing its contacts directly: if the refrigerator is working, then the problem is in it.
How to check a thermostat with a multimeter?
To check a mechanical thermostat, remove it and ring the contacts with a tester in resistance measurement mode. At room temperature the contacts should be closed (resistance close to 0). If you put the thermostat in the freezer for 15-20 minutes, the contacts should open.
Replacing the thermostat is a procedure that you can do yourself if you have basic skills in working with tools. However, it is important to choose an analogue with exactly the same characteristics, otherwise the refrigerator will not work correctly: either constantly freeze or turn off frequently.
Faults in the starting relay and compressor
If, when you turn on the refrigerator, you hear a click, followed by a buzzing sound that lasts a few seconds, and then another click and silence - this is a sure sign of problems with starting engine. In this case starting relay, which supplies the initial impulse to the compressor winding, could burn out or stick. This is a consumable item that often fails due to power surges in the network.
A more serious problem is the malfunction of the compressoritself. The engine could burn out due to an interturn short circuit or a wedge in the piston group. In this case, even with a working relay, the engine will not start. Compressor diagnostics require checking the windings with a multimeter. The normal resistance between the contacts should be in the range of 10-30 Ohms (depending on the model). If the device shows an open circuit (infinity) or a short circuit (zero), the compressor must be replaced.
☑️ Compressor diagnostics
It is worth noting that replacing a compressor is difficult a process that requires evacuation of the system and charging with freon. It is impossible to perform this operation on your own without special equipment, so if the diagnosis is confirmed, you will have to call a specialist.
Freon leakage and violation of the tightness of the circuit
The most insidious reason why the refrigerator lights up but does not cool is refrigerant leak (freon). Freon circulates in a sealed circuit and, evaporating, takes heat from the chambers. If a microcrack has formed in the tubes (due to corrosion, mechanical damage or manufacturing defects), the gas gradually evaporates. Visually, you may not notice this, since freon is colorless and odorless.
Leak symptoms appear gradually. At first, the refrigerator begins to work longer than usual, then a “snow coat” may appear on the back wall of the freezer only in one corner, and over time, cooling stops completely. The compressor may hum continuously, trying to compensate for the lack of refrigerant, but this has no effect.
| Symptom | Description of the symptom | Probable cause |
|---|---|---|
| Heat in both chambers | The food is spoiling, the light is on | Complete freon leak |
| Hot condenser | The rear grill is only partially hot | Clogged or partial leak |
| Continuous operation | Compressor does not turn off | Trying to gain temperature |
| Bloating of the wall | Bloating of the inner wall | Evaporator corrosion inside |
⚠️ Attention: Having discovered an oily stain under the refrigerator or on the tubes of the compressor, you should know that this is almost guaranteed to be a place of freon leakage, since the oil comes out along with the gas.
Restoring the tightness and filling the system with freon is a task for professionals. It is important not only to find the hole and seal it, but also to correctly calculate the amount of refrigerant and oil. Overfilling or underfilling will lead to rapid breakdown of the compressor.
Clogged capillary tube
There is a narrow section in the freon circulation system - capillary tube. This is where a sharp drop in refrigerant pressure occurs, which provides cooling. If there is moisture or oxidation products in the system (after poor-quality past repairs), they can clog this narrow passage. As a result, freon cannot circulate through the circuit, and cold does not enter the chambers.
The blockage can be diagnosed by characteristic signs: the compressor operates very loudly, overheats, and the condenser (grid at the back) remains cold or warm only at the very outlet of the compressor. The pressure in the system increases sharply, which puts a load on the engine. Sometimes “pushing” the system with nitrogen helps, but more often the filter-drier and capillary tube need to be cleaned or replaced.
This problem often occurs after the refrigerator has been improperly filled, when air or moisture gets into the system. This is why it is so important to contact trusted specialists who use a vacuum pump to remove air before refueling.
Failure of the control module (electronics)
In modern refrigerators with a system Full No Frost and displays on the door, it is responsible for all processes electronic control module. If it is "buggy", it may simply not issue a command to turn on the compressor, although the display on the panel may work normally. Often such failures occur after power surges.
Sometimes a simple one helps. error reset. To do this, you need to unplug the refrigerator from the outlet for 15-20 minutes, and then turn it on again. If the problem was a software glitch, the system will restart and work correctly. If the module is physically burned out (blackened elements are visible, a burning smell), it will require replacement or complex repair of the board.
The cost of control modules is high, and replacing them is an expensive repair. Before buying a new board, you should make sure that the problem is not in the wiring or sensors that send incorrect signals to the “brains” of the refrigerator.
Problems with the defrost system (for No Frost)
If you have a system refrigerator No Frost, and it stopped freezing when the compressor is running, there may be a failure in the system evaporator defrost. The defrost heating element, timer or defrost sensor may have failed. As a result, the evaporator becomes covered with ice, which blocks the circulation of cold air. The fan moves the air, but it cannot pass through the ice plug to the food.
In such cases, completely defrosting the refrigerator within 24 hours often helps. If after this the unit begins to freeze normally for a couple of days, and then stops again, the problem is definitely in the defrosting system. You need to check the chain: Heating element -> Defrost sensor -> Timer/Module.
Mechanical damage and wear of seals
Sometimes the reason for the loss of cold is trivial and is located outside. If sealing rubber band the door is worn out, dirty or deformed, warm air from the room constantly enters the chamber. The compressor works hard, trying to cool this volume, but cannot cope. Visually this may not be noticeable, but the heat exchange is disrupted.
You can check the tightness using a sheet of paper. Clamp the sheet with the door around the perimeter. If it comes out easily and without resistance, the seal does not fit. It is also worth checking the door hinges: if they are loose, the door warps and does not close tightly.
In addition, frequently leaving the door ajar or loading hot food can also lead to temporary loss of cold. In such cases, the unit simply needs time to restore the temperature.
Why does the refrigerator hum but not freeze?
If you hear a hum, it means the compressor is trying to work. Most likely, the problem is a freon leak, a clogged capillary tube, or a stuck start relay, which prevents the engine from starting fully.
Is it possible to operate a refrigerator if it does not freeze?
It is strictly not recommended. The compressor will work continuously, trying to gain temperature, which will lead to overheating and eventual failure. It is better to turn off the device until the reasons are determined.
How much does it cost to repair if the refrigerator stops cooling?
The cost depends on the breakdown. Replacing the thermostat or start relay is inexpensive. Freon refilling and leak detection are more expensive. Replacing the compressor is the most expensive option, often comparable to buying used equipment.
What to do if it is warm in the refrigerator and ice in the freezer?
This is a characteristic sign of a malfunction of the defrost system (for No Frost) or a freon leak. There may be residual ice in the freezer, but no new portion of cold is supplied. Diagnostics by a technician is required.