The situation when the refrigerator is workingmakes the usual noise, but stops cooling food, is one of the most alarming for the owner. Internal panic is understandable: food spoils, and calling a technician or buying new equipment requires significant funds. However, the problem does not always lie in a fatal breakdown of the main unit. Often the reason lies in a violation of the tightness of the system, electronic failures, or even a banal overload of the freezer with ice, which blocks air circulation.
The first thing you need to do when you hear that motor-compressor it is humming, but there is no cold, is listen to the nature of the technology. If the unit turns on, runs for a few minutes, then there is a click and it turns off, and after a while the cycle repeats, this indicates overheating or problems with the starting mechanism. In cases where the equipment works continuously for days, but the temperature inside remains room temperature, we are most likely talking about refrigerant leak or a clogged capillary tube.
It is important to understand that modern models, whether then Indesit, Atlant or Boschhave complex control systems. Sometimes the lack of cold is the result of an error in the sensors, which “think” that the temperature is normal and do not give a command for active cooling. Before sounding the alarm, it is worth carrying out a primary diagnosis to exclude simple factors, such as a loosely closed door or a damaged seal.
Primary diagnosis: can you hear the sound of a running compressor
Diagnostics always begin with an analysis of the sound. If you walk up to your refrigerator and hear a steady, monotonous hum, the compressor motor is trying to work. However, noise itself does not guarantee that the piston group creates the necessary pressure for circulation freon. The compressor may hum “idle” if there is a mechanical breakdown of the valves inside it.
⚠️ Attention: If you hear a metallic knock, clanging or strong vibration of the housing during operation, immediately disconnect the device from the network. Continuing operation in this mode will lead to the final destruction of the compressor and will make its restoration impossible.
If the motor is silent, but the light inside is on, the problem may lie in the start relay or thermostat. The relay is responsible for supplying voltage to the motor windings when starting. If it burns out, the engine will not start, despite the presence of electricity in the outlet. Checking this element requires a multimeter or visual inspection for melting and a burning smell.
It is also worth paying attention to the temperature of the rear wall or condenser (grid at the back). If the compressor is running but the grate remains cold, this is a sure sign that there is no gas circulation. Normally it should be warm or hot. If only part of the grate is hot, and the rest is cold, there may have been a formation clogging in the system or the tube has become pinched.
Refrigerant leakage: symptoms and places of probable damage
The most common cause is why the refrigerator does not freeze, while the motor runs without stopping, is a banal freon leak. The refrigerant is the working fluid of the system, which, as it evaporates, takes away heat. If its quantity in the circuit has decreased critically, cooling stops. Freon is not consumed during operation, so its disappearance always indicates a violation of the seal.
Most often, leaks occur in hidden places that cannot be seen without special equipment. In models with the No Frost system, the evaporator is often foamed in the housing walls, and damage can occur due to corrosion. In older models with an open condenser on the back wall, the cause is rust or mechanical damage due to careless cleaning.
You can visually determine the leak by swelling of the wall inside the chamber or the appearance of oily spots under the refrigerator (oil comes out along with the gas). However, most cases require the use of a leak detector or a soap solution that is applied to the joints. If bubbles appear, it means the seal is broken.
Is it possible to fill the refrigerator yourself?
Self-refueling is impossible without a vacuum pump and scales. Trying to simply “add gas” through the Schrader valve will result in air and moisture entering the system, which will cause the formation of an ice plug and failure of the compressor in a short time.
It is important to note that after eliminating the leak and sealing the hole, the system must be thoroughly evacuated. This removes moisture and air, which are the main enemies of the refrigeration circuit. Residual moisture will freeze in the capillary tube and block the system again.
Clogged capillary tube and ice plug
The capillary tube is a thin copper pipe that separates the high and low pressure zones in the system. Its diameter is extremely small, so even a microscopic particle of debris that gets into the circuit during poor-quality repairs or due to destruction of the insulation of the motor windings can cause clogging. When clogged, freon cannot circulate, and the cooling capacity drops to zero.
The symptoms of a clog are often similar to a leak: the compressor works, but does not freeze. They can be distinguished by the temperature of the compressor. When clogged, it often overheats as it pumps gas into the “locked” system. There may also be a lack of characteristic gurgling and hissing when the device is turned off.
- ❄️ Ice plug: occurs due to moisture entering the system, which freezes in a narrow place in the capillary.
- 🛠️ Mechanical blockage: caused by copper oxides, burnt oil or debris after soldering.
- 🔨 Pinching of the tube: mechanical damage during transportation or installation, narrowing the passage.
To eliminate the ice plug, sometimes it is enough to defrost the refrigerator in the off state for 24 hours. If the problem is a mechanical blockage, professional purging of the system with nitrogen under pressure and replacement of the filter-drier are required.
Compressor malfunctions: when the motor is “powerless”
The compressor is the heart of the refrigerator. The situation when it hums but does not pump is called a “compressor without pressure.” This occurs when the suction or discharge valve inside the housing breaks down. Valves are thin plates that lose elasticity over time or break due to water hammer (ingress of liquid freon).
You can diagnose this malfunction by biting off the capillary tube and discharge tube (only for professionals!). If, when turned on, there is no powerful air flow from the discharge tube and no pressure is created, then the compressor requires replacement. Sealed units cannot be repaired.
Another reason for poor motor operation may be an interturn short circuit of the windings. In this case, the engine tries to start, hums, but does not gain momentum. Often in such cases, the thermal protection relay is triggered and the unit is turned off. Checking the resistance of the windings with a tester helps to identify a breakdown in the housing or a violation of the integrity of the turns.
| Symptom | Probable cause | Nature of motor operation | Condenser temperature |
|---|---|---|---|
| Works, does not freeze | Freon leak | Works without stopping | Cold or barely warm |
| Buzzes, clicks, turns off | Compressor / Relay jammed | Short-term attempts to start | Does not have time to heat up |
| It freezes slightly | Clogged capillary | Works long | Hot, but unevenly |
| Does not freeze, makes noise | Valve failure | Works smoothly, but quietly | Warm |
Problems with the No Frost system and sensors
In refrigerators with the system No Frost the lack of cold when the compressor is running is often associated with a malfunction of the defrost system. If the defrost heating element, defrost thermostat or timer (electronic module) fails, the evaporator becomes covered with a “coat” of ice. This ice blocks the channels through which the fan should blow cold air into the chambers.
As a result, the compressor works, trying to cool the evaporator, but no air enters the chamber. The user sees (or hears) the fan running, but the food is warm. To check, you must defrost the unit manually for 24 hours. If after turning on the cold appears for 5-7 days, and then disappears again, the problem is definitely in the defrosting system.
⚠️ Attention: Do not try to break off the ice from the evaporator with a knife or sharp objects. Damage to the evaporator tubes in the No Frost system will lead to expensive repairs involving opening the housing or replacing the entire unit.
Also in modern models, temperature sensors are responsible for everything. If the sensor “lies” and shows the control module that it is already -20°C in the chamber, the controller will simply not turn on the compressor or turn it on for a short time. Replacing the sensor is a simple procedure, but requires precise selection of an analogue in terms of resistance.
☑️ No Frost diagnostics
Influence of the environment and proper operation
Sometimes the reason for the lack of cold lies not in the breakdown, but in the operating conditions. If the refrigerator is placed close to the wall, there is no air flow to the radiator from the back, which leads to overheating and reduced efficiency. Ambient temperature is also critical: most models are not designed to operate in unheated rooms at temperatures below +10°C or above +32°C.
At low temperatures, the oil in the compressor thickens, and it may not start or work with overload. At high ambient temperatures, the condenser does not have time to give off heat, the pressure in the system increases, and the protection is triggered. It is important to maintain clearances during installation: at least 5-10 cm from walls and cabinets.
Frequently opening doors or loading hot products can also disrupt the work cycle. In such cases, the motor will run continuously, trying to compensate for the heat gain, but due to overload, the cooling efficiency will drop. Give the equipment time to get into operation without loading it with products in the first hours after switching on.
FAQ: Frequently asked questions
Why does the refrigerator hum, but does not freeze after defrosting?
If after complete defrosting (more than 24 hours) the cold has not appeared, it has probably occurred Freon is leaking or a blockage has formed. During the defrosting process, water could get into the electrical parts, but more often the problem lies in the fact that the seal was broken even before defrosting, and you simply did not notice it.
Is it possible to add freon yourself through the valve?
No, you cannot. For high-quality refilling, you need to know the exact brand of refrigerant, its weight, use a vacuum pump to remove moisture and air, and also have a pressure gauge station. Simply adding gas “by eye” will lead to breakdown of the compressor.
How long should the compressor work normally?
Under normal conditions, the compressor operates cyclically: it works for about 10-20 minutes, rests for 20-40 minutes. The work rate is approximately 30-50%. If it works constantly without stopping and does not freeze, this is an emergency mode.
What to do if after a power surge the refrigerator stops freezing?
Most likely, the start relay has burned out or the control module has failed. In the worst case, the compressor itself could burn out. It is necessary to call a technician to diagnose the electrical circuit.