The situation when it gets warm inside the refrigeration chamber, food begins to deteriorate, and the unit continues to hum and work, is one of the most stressful for the owner. It seems that the technology has gone crazy: the motor-compressor is working hard, trying to produce cold, but there is no desired result. This is a sure sign that a failure has occurred in the closed refrigerant circulation system, or heat transfer is impaired.
Before calling a technician or panicking, it is important to understand the physical essence of the process. The refrigerator does not produce cold, it transfers heat from the chamber to the outside. If the engine is running, then the electrical circuit is intact and the mechanical part of the compressor is trying to function. However, the absence of cold indicates that the thermodynamic cycle is interrupted or ineffective. In this article we will analyze in detail all possible causes, from simple operating errors to complex technical malfunctions.
Understanding the operating principle will help you quickly diagnose the problem. Most often, the culprits are a freon leak, a clogged capillary tube, or a breakdown of the electronics that control the modes. Let's look at each scenario one by one so that you can make an informed decision on further actions.
The main reasons for the lack of cold when the engine is running
The most common reason why refrigerator it stops freezing when the compressor is running is a banal refrigerant leak. Freon circulates in a closed loop, and if a microcrack appears in the system, the gas gradually evaporates. As a result, the compressor continues to pump, but there is nothing to pump, or the pressure in the system drops to a critical minimum.
The second common culprit is clogging of the capillary tube. During operation, oil breakdown products may form in the system or moisture may enter, which freezes in a narrow place in the tube, forming an ice plug. This blocks the circulation of freon, and the cold does not enter the evaporator.
It is also worth considering the wear of the compressor itself. The motor may hum and even start, but it valve group may be worn out. In this case, the compressor does not create the necessary pressure to compress and move freon through the system. It works “idle”, simulating activity, but not performing its function.
Don’t forget about the thermostat or temperature sensors. If thermostat stuck in the “on” position, the compressor will work continuously, trying to reach a non-existent temperature, or, conversely, will not receive a signal to start the cooling cycle, although formally power can be supplied to it through bypass circuits in some models.
Diagnostics of freon leakage: how to check it yourself
A refrigerant leak is not just a loss of efficiency, it is the risk of complete failure of the system if air gets inside and moisture It is rarely possible to detect a leak visually, since freon is colorless and odorless. However, there are indirect signs that will help you suspect this particular problem.
First of all, pay attention to the operation of the compressor. When there is a leak, it often works without interruption, trying to compensate for the lack of cold. If you notice that the refrigerator is humming 24 hours a day, but the temperature inside does not drop, the likelihood of a leak is very high. Also check the back wall or condenser (grill at the back). Normally it should be warm or hot. If the grill is cold, although the motor is running, this is an almost guaranteed leak.
Another method is to visually inspect the tubes leading to the compressor. If you see traces of oil or rust at the joints (soldering), this is a sure sign that freon is poisoning there. Oil often comes out along with gas.
⚠️ Attention: Self-filling the refrigerator with freon without evacuating the system and replacing the filter-drier is strictly prohibited. An attempt to simply “add gas” will lead to the formation of an ice plug in the capillary and the final breakdown of the compressor in a short time.
For accurate diagnosis, technicians use leak detectors or the nitrogen pressure test method. At home, you can only state the fact that there is no cold when the engine is running and the radiator grill is cold.
Problems with the compressor: when the motor “hums, but does not pump”
The compressor is the heart of the refrigerator. If it works, but does not create the necessary pressure, the refrigerator turns into an ordinary cabinet. This condition is often called “the compressor does not pump.” This occurs due to breakage of the valves inside the cylinder or wear of the piston group.
This problem can be diagnosed by the temperature of the nozzles at the outlet of the compressor. During normal operation, one pipe (discharge) should be very hot, and the other (suction) should be cold or at room temperature. If both pipes have the same temperature (for example, both warm or both cold) when the engine is running, then compression is not occurring.
It is also worth checking the start relay. Sometimes the relay clicks, trying to start the engine, the compressor hums for a few seconds and turns off. But in your case, judging by the condition, the engine runs constantly. This means that the electrical part is working, but the mechanical efficiency has dropped to zero.
| Symptom | Probable cause | Characteristic sound |
|---|---|---|
| Compressor is hot, grille is cold | Freon leak | Smooth humming |
| The compressor is warm, both pipes are the same | Valve malfunction | Humming with a metallic tint |
| The compressor vibrates, there is no cold | Breakage of the internal suspension | Strong knocking and vibration |
| The motor hums for 5 seconds and clicks | Stuck or relay | Click and silence |
Is it possible to replace the compressor yourself?
Theoretically, yes, if you know how to work with gas and solder copper tubes. However, this requires special equipment: a burner, a vacuum pump, a pressure gauge station and a filling scale. Without these tools, a high-quality replacement is impossible.
Clogged capillary system and ice plug
The capillary tube is a very thin copper channel that serves as a choke in the cooling system. Its diameter is less than a millimeter, so it clogs (very easily). The causes of blockage are divided into two types: mechanical (oil breakdown products, copper oxide) and ice (moisture entering the system).
If the blockage is mechanical, the symptoms will increase gradually. The refrigerator will start to freeze worse, the compressor will work longer. Over time, the cold will disappear completely. In this case, the condenser (grid at the back) can heat up only in the initial part, and then remain cold.
In the case of an ice plug, the situation is more interesting. Moisture enters the system due to poor quality repairs or depressurization. Passing through the capillary, it freezes and blocks the freon flow. A characteristic feature: the refrigerator can periodically “thaw” on its own. When the compressor turns off (by timer or overheating), the plug melts, freon passes through, and cold appears. Then the cycle repeats.
☑️ Signs of a clogged system
Removing the blockage requires purging the system with nitrogen under high pressure and replacing the filter-drier. At home, it is almost impossible to perform this procedure efficiently.
Malfunctions of the No Frost system and sensors
If you have a modern refrigerator with the system No Frost, the lack of cold when the compressor is running may be due to problems in the defrost system. In such units, the cold is produced in a separate evaporator (often hidden behind a plastic panel) and is pumped by a fan into the chambers.
If the defrost timer or defrost sensor fails, the evaporator becomes overgrown with ice. The fan continues to circulate air, but the ice coat blocks the heat exchange. The compressor works non-stop, trying to cool the air, but the cold simply does not pass through the ice shell. Defrost heating element, defrost timer or defrost sensor, the evaporator is covered with ice. The fan continues to circulate air, but the ice coat blocks the heat exchange. The compressor works non-stop, trying to cool the air, but the cold simply does not pass through the ice shell.
You can diagnose this by listening to the operation of the fan. If it hums, but air does not blow from the holes in the chamber (or barely blows), it means that the air ducts are clogged with ice. Another sign may be the presence of water under the vegetable drawers, which flows out when the door is opened.
⚠️ Attention: Do not try to remove the ice with a knife or sharp objects! You may damage the aluminum evaporator, making repairs no longer economically feasible. Defrost the chamber naturally, leaving the doors open for at least 24 hours.
Also in the No Frost system, temperature sensors (thermistors) often fail. If the sensor “lies” and shows that the chamber is already -30°C, the compressor may not turn on or operate in the wrong mode. Although in your case the motor is working, a faulty sensor may not give a command to turn on the defrost heating element, which ultimately leads to freezing.
The influence of improper operation and external factors
Sometimes the reason lies not in the breakdown of parts, but in the operating conditions. If the refrigerator is close to the wall, it has no ventilation. The compressor overheats, efficiency drops, and even with constant operation, no cold is generated. The gap between the back wall and the wall should be at least 5-7 cm.
The room temperature is also critical. If you place the refrigerator on an unheated balcony in winter, the oil in the compressor thickens and it cannot work normally, even if it hums. In summer, at temperatures above +35°C, the refrigerator may not be able to cope with the heat flow, operating at its maximum capacity.
Frequently opening the door or adding hot food also leads to the fact that the unit does not have time to freeze. The compressor works, but heat enters faster than it is removed.
When you need to call a technician, and when you can handle it yourself
If the problem is improper installation, contaminated condenser or the need for complete defrosting, you can handle it yourself. Clean the radiator from behind from dust, check the tightness of the door seal and defrost the chamber for a day.
However, if after defrosting (24 hours with the doors open) the refrigerator turned on, worked for a couple of hours and again stopped freezing with the motor running - this is “hardware”. A leak, blockage or breakdown of the compressor requires the intervention of a professional with the equipment.
Repairing a sealed circuit (replacing a compressor, finding a leak, replacing a capillary) is a complex procedure. It includes:
1. Opening the circuit.
2. Burning out old freon.
3. Nitrogen purging.
4. Soldering new parts.
5. Vacuuming (removing moisture and air).
6. Accurate refilling with freon by scale.
How much does a repair cost if the refrigerator does not freeze?
The cost depends on the breakdown. Refilling with freon is usually cheaper than replacing the compressor. However, the exact price can only be announced after diagnosis. Replacing a compressor is the most expensive repair, often amounting to 60-70% of the cost of a new refrigerator.
Is it possible to use a refrigerator if it does not freeze, but works?
Short-term - yes, but keeping it on for a long time in this mode is dangerous. The compressor wears out, the oil may not return, which will lead to its combustion. It is better to turn off the appliance before the technician arrives.
Why did the refrigerator start working after defrosting, but after a week it stopped again?
This is a classic sign of moisture getting into the system (ice jam) or a beginning leak. Defrosting temporarily removes ice, but does not remove the cause of its appearance. Replacement of the filter-drier and vacuuming are required.
How often do you need to defrost a No Frost refrigerator?
The No Frost system does not require regular defrosting to remove ice, as it does it automatically. However, once every year or two it is recommended to defrost it for hygienic washing and cleaning hard-to-reach places from dust.