The situation when you open the refrigerator door and see a light on, but there is a warm atmosphere inside, and the food begins to spoil, causes panic. This is a classic sign that the electrical circuit is fine, but the cooling system has failed. The light is on because there is voltage at the input plug and the lamp power circuit is not broken, however compressor or the control system does not start the cooling process. At such a moment, it is important not to waste time, since food can spoil in a matter of hours, especially in the summer.
The first thing you need to do is listen to the operation of the unit. If you hear the hum of the motor, but there is no cold, or there is absolute silence, the action algorithms will be different. Two-compressor models they may behave differently than single-compressor ones, so initial diagnosis requires care. You should not immediately call a technician if the problem lies in a banal defrosting or an electronics failure, which you can fix yourself.
In this article we will analyze in detail the mechanical and electrical causes of failure, diagnostic methods and steps that will help bring the equipment back to life. Understanding the principles of operation refrigeration circuit will help you more accurately describe the problem to a specialist or even solve it on your own. We will consider both simple cases and complex breakdowns that require professional intervention.
Primary diagnosis: listen and check
Before disassembling the back wall or looking for tools, it is necessary to conduct a visual and auditory analysis. Go to the refrigerator and place your hand on the sides or the condenser grille at the back. If they are cold even though the compressor is running, that's one scenario. If the motor hums, but after 10-15 seconds a click is heard and it goes silent, this indicates problems with starting. Start relay or the motor itself may be faulty.
In modern models with the system No Frost diagnosis is complicated by the presence of many sensors If you hear that the fan is running, but no cold air is flowing into the chambers, the ducts may be clogged or there is a failure in the control unit. It is important to check whether the temperature alarm indicator on the control panel is lit. Its activation confirms that the electronics “see” a problem with the temperature regime.
⚠️ Attention: If you smell burning or see sparking in the compressor area, immediately unplug the device. Further operation may lead to a fire or complete burnout of the wiring.
Check the tightness of the door. Sometimes the light is on because the door is open or poorly closed, and at this moment the compressor may not turn on due to the operating logic of some models, or, on the contrary, may run idle if the door sensor is stuck. Make sure that the food does not interfere with the tight closure, and that the sealing rubber is clean and elastic.
Mechanical malfunctions of the compressor and relay
One of the most common reasons why equipment stops freezing is the failure of the start-up relay. This small element is responsible for supplying current to the motor windings at startup. If the relay is burned out or stuck, the compressor will either not start at all, or will try to start, making a characteristic click, and then go into protection. Replacing this part is a relatively simple procedure, accessible even to beginners.
A more serious problem is an interturn short circuit in the windings itself compressor. In this case, the motor may hum, heat up, but not develop the required pressure for refrigerant circulation. You can check the integrity of the windings using a multimeter by ringing the contacts. If the resistance tends to zero or infinity, the unit will need to be replaced, which is an expensive repair.
It is also worth paying attention to the operation of the motor over time. If it turns on, works for a couple of minutes, then turns off, but there is still no cold, perhaps the problem is thermal expansion of the parts or lack of lubrication. Inverter compressors they are quieter and change speed smoothly, so sharp clicks are uncharacteristic for them and indicate a serious electronics failure.
☑️ Diagnostics of the compressor unit
Freon leak and capillary system clogged
If the compressor runs continuously, without turning off, hums smoothly, but the chambers are warm, there is a high probability of leakage refrigerant. Freon can escape through microcracks in the evaporator, which are formed due to corrosion or mechanical damage due to careless defrosting with a knife. It is impossible to visually see the gas, but an indirect sign is the lack of heating of the condenser grill at the back.
Another option is a clogged capillary tube. An ice or oil-paraffin plug may have formed in the refrigerant circulation system. In this case, the pressure in the system increases sharply, the compressor operates with overload, but the circulation of freon stops. A characteristic sign is that part of the condenser may be hot and the other part cold.
To eliminate these problems, you need to call a technician with professional equipment. It is necessary to find the leak, solder it, evacuate the system and fill it with new freon in strict accordance with the technical data sheet of the model. It is impossible and dangerous to perform these actions on your own without vacuum pump a pressure gauge station.
| Symptom | Probable cause | Nature of motor operation | Need a technician |
|---|---|---|---|
| Silence, there is light | Relay or thermostat burned out | Does not turn on | Medium |
| Buzzes, clicks, turns off | Compressor jammed | Short start | High |
| Works constantly, no cold | Freon leak | Continuous | High |
| Noisy, little cold | Capillary clogged | Intense | High |
Problems with the defrosting system (No Frost)
In refrigerators with a system No Frost a common reason for cooling to stop is a malfunction of the defrosting system. If the evaporator heating element, timer or defrost sensor fails, a “coat” of ice builds up on the evaporator. The fan cannot drive air through the ice shell, and the cold stops flowing into the chambers, although the compressor itself may work properly.
You can diagnose this problem by looking into the freezer (sometimes you need to remove the back panel). If you see a thick layer of ice or snow blocking the channels, the problem has been found. Often in such cases, it is triggered defrost sensor, which erroneously informs the control unit that the temperature has already been reached, or, conversely, prevents heating from starting to remove ice.
The solution may be to completely defrost the refrigerator in the off state for 24 hours. If after switching on the equipment works normally, then the problem was temporary. However, if the situation repeats after a week, the heating element or sensor will need to be replaced. This is a typical “disease” of age models.