The situation when you open the refrigerator door, and there is room temperature, although the hum of a running motor comes from the kitchen, is one of the most alarming for the owner. At this point, it becomes obvious that a serious failure has occurred inside the cooling system, which does not allow the production of cold, despite the visible activity of the unit. Often, equipment owners continue to operate the device in the hope that it will “lose” or “work on its own,” but this only aggravates the situation and can lead to complete damage to the products.
Understanding that compressor runningbut there is no cold, narrows the range of possible causes to a few key components: the refrigerant circulation system, thermoregulation, or the mechanical integrity of the circuit. Ignoring the problem at the initial stage can lead to expensive repairs becoming economically unfeasible. In this article we will analyze in detail why this happens, how to carry out initial diagnostics and what steps to take to restore the functionality of your refrigerator cabinet.
The main reasons for the lack of cold when the compressor is running
The most common and, alas, the unpleasant cause is refrigerant leak (freon). In good condition, the gas circulates in a closed circuit, changing its state of aggregation and removing heat from the chambers. If a microcrack has formed in the tubes due to corrosion or mechanical damage, the gas gradually evaporates into the atmosphere. The motor continues to hum, trying to pump through what is left in the system, but the pressure is no longer enough to create cold.
The second common problem becomes clogged capillary tube. During operation, oil oxidation products or moisture may accumulate in the system, which turns into an ice plug. This prevents the normal circulation of freon. The compressor tries to push through the plug, works with overload, but heat exchange does not occur. It is also impossible to exclude a breakdown of the compressoritself: it may hum, but not create the necessary pressure due to wear of the valves or piston group.
⚠️ Attention: If you hear, that the motor hums, then a click is heard and it goes silent, after which the cycle repeats - this is a sign that the thermal protection relay has tripped. Do not try to constantly plug the device into the network, this may completely burn out the motor windings.
The third reason lies in malfunctions thermostat or the electronic control module. If the temperature sensor is “stuck” or transmits incorrect data, it may not give a command for full cooling, or, conversely, not turn off the motor when the cold has already been reached (although in the latter case the refrigerator usually freezes too much). In modern models with the system No Frost the problem may lie in the failure of the fan, which simply does not blow the cold through the chambers.
- 🔍 Freon leakage due to corrosion of the evaporator or mechanical damage to the tubes.
- 🧊 Formation of an ice plug or blockage in the capillary system.
- 🛠️ Wear of compressor valves when there is no compression.
- 🌡️ Malfunction of the thermostat or temperature sensors.
Diagnostics systems: how to understand what happened
Before calling a technician, you can conduct a series of visual and auditory checks that will help a specialist more accurately describe the problem. First of all, pay attention to exactly how the motor works. If it hums smoothly and continuously but is warm inside, this almost always indicates a leak or clog. If you hear an intermittent hum with periodic clicks, the problem may be in the start relay or the compressor itself.
Carefully inspect condenser (the grille at the back of the refrigerator or hidden in the side walls). In normal mode, it should be warm or hot evenly over the entire area. If you feel the grille and realize that it is cold, although the motor has been running for several hours, it means that the freon has either left or is not circulating. If only the part of the grille near the compressor is hot, and then it cools down, there is a blockage.
It is also worth checking the operation of the system No Frost. Open the freezer and listen. If the compressor is running but you do not hear the characteristic fan noise, it may be frozen or damaged. In this case, cold is produced, but does not enter the refrigerator compartment. Another important indicator is the condition of the evaporator. If you can look behind the back wall of the freezer (by removing the plastic), pay attention to the ice.
- ❄️ Uniform light frost throughout the evaporator is the norm.
- 🌨️ Local “coats” of ice or a “snow coat” in one corner are a sign of a leak freon.
- 💧 A completely dry and clean evaporator with the engine running is a sign of complete loss of freon.
Refrigerant leak: symptoms and consequences
Freon leak is the “silent killer” of your refrigerator. Since modern refrigerants are odorless and colorless, it is impossible to visually detect their leakage. However, the consequences for the operation of the unit are catastrophic. Without a sufficient amount of working fluid in the circuit, the pressure drops, and boiling of freon occurs not in the evaporator (where it needs to be cooled), but in other parts of the system or does not occur at all.
Often a leak occurs at the place where the tubes are sealed or in the foamed part of the housing where the system is located No Frost. Over time, moisture that enters when doors are opened causes corrosion of the aluminum. First, the refrigerator begins to freeze worse, then the motor starts working almost non-stop, trying to reach the set temperature, which it physically cannot reach. As a result, the compressor overheats and may burn out.
| Symptom | Probable cause | Required actions |
|---|---|---|
| Compressor hot, condenser cold | Complete leak freon | Finding the leak, evacuation, refilling |
| Ice coat in one corner of the freezer | Partial leak | Repairing the circuit or replacing the evaporator |
| Motor works without stopping | Lack of refrigerant | Diagnostics of pressure in the system |
| Bloating of the refrigerator wall | Corrosion inside the case | Complicated repairs with opening thermal insulation |
⚠️ Attention: Self-filling the refrigerator with freon is impossible without special equipment (vacuum pump, pressure gauge station, scales). An attempt to simply “add gas” without eliminating the leak and evacuating the system will lead to rapid failure of the compressor.
Circulation problems: blockages and plugs
Clogged capillary tube is the second most popular reason why the refrigerator does not freeze. A capillary is a very thin tube where freon sharply expands and cools. Even a microscopic piece of debris or a clot of oil can block this passage. As a result, freon accumulates in front of the plug, without getting into the evaporator, and the cooling cycle is interrupted.
Often the blockage is accompanied by a characteristic sign: the filter drier (the metal cylinder near the compressor) may become covered with frost or, conversely, be very hot at the inlet/outlet point. There may also be a phenomenon when, after defrosting for 24 hours, the refrigerator begins to freeze, and then stops again. This indicates that the plug was icy (moisture in the system), it melted, allowed to work, but then froze again in the narrowest place.
To eliminate this problem, you need blowing the system nitrogen under high pressure and replacing the filter drier. It is extremely difficult to do this at home, since access to the process pipe and skills in working with a blowtorch are required. If you do not replace the filter, a new blockage will form very quickly.
- 🚫 An attempt to break through the blockage by increasing pressure can rupture the thin-walled evaporator tubes.
- 🔥 Using an open flame during defrosting (hair dryer, heater) can melt plastic parts and damage the wiring.
- 🛑 Adding oil to the system indiscriminately can aggravate the situation and create new plugs.
Faults of the compressor and start relay
You may get the false impression that the engine is running, when in fact it is only humming, trying to start. The engine is started by a starting relay. If it is faulty, the motor windings receive power, a hum is heard, but the shaft does not rotate. After a few seconds, the thermal protection is activated and a shutdown click is heard. The cycle repeats.
A more complex case is turn-to-turn short circuit or wear of the valves inside the compressor. In this case, the engine may run continuously, make increased noise, but not develop the required compression. The outlet pressure will be low and the freon will not circulate at the required speed. You can check the compression by disconnecting the tubes and briefly turning on the motor (be careful, there will be strong air pressure), but it is better to entrust this to a professional.
How to check the start relay yourself?
Disconnect the refrigerator from the network. Remove the back cover and locate the black box on the side of the compressor. Carefully remove it and shake it near your ear. If something rattles inside (like a coin), it means that the starting coil is damaged and the relay needs to be replaced. This is a frequent and inexpensive breakdown.
Replacing a compressor is a complex and expensive process that requires:1. Cream of freon residues; 2. Dismantling the old motor; 3. New installations with selection according to power; 4. Soldering tubes; 5. Vacuuming and refueling. Often the cost of such repairs is 50-70% of the price of a new refrigerator, so the feasibility of the operation must be assessed individually.
Failures in the electronics and No Frost system
In modern models, the electronic control module is responsible for all processes. If the “brains” of the refrigerator receive incorrect data from the sensors, they may not turn on the compressor at full power or not start the fan. For example, if the defrost sensor indicates that the evaporator is hot, the module may not start the refrigeration cycle, believing that there is already cold.
Particular attention should be paid to the system No Frost. If the fan that circulates air or the defrost heating element, which is supposed to melt the ice on the evaporator, fails, the system quickly becomes clogged with ice. The air stops circulating and the chambers become warm. In this case, the compressor may work normally, trying to cool an already frozen block of ice in the freezer.
Diagnostics of electronics requires a multimeter and knowledge of circuit design. Burnt tracks or swollen capacitors are often visually visible on the board. Repairing the module is possible, but sometimes it is cheaper and more reliable to replace the entire board, reprogramming it for your model.
When you need to call a technician: checklist
There are a number of situations when independent repair is not only useless, but also dangerous. If you do not have experience working with refrigeration equipment and tools, it is better not to take risks. This is especially true for work related to violation of the tightness of the circuit.
☑️ Do you need a technician?
Calling a specialist is required if required:1. Soldering copper or aluminum tubes; 2. Evacuation of the system; 3. Accurate freon filling by weight; 4. Replacing the compressor or filter drier. A professional technician has sealant, freon, oil and tools for finding leaks (leak detector), which cannot be reproduced at home.
⚠️ Attention: Freon used in refrigerators forms toxic phosgene when in contact with an open flame (for example, when soldering without removing the gas). Be careful and follow safety precautions when any manipulations with the refrigeration circuit.
Prevention and extension of service life
So that the situation “works, but does not freeze” does not take you by surprise, it is important to follow the operating rules. Regular but not too frequent defrosting (every 6-12 months for a drip system) will help keep the system clean. Do not load warm products into the chamber - this creates extra load on the compressor and contributes to the formation of excess ice.
Keep the condenser clean. If you have a refrigerator with an open grille at the back, periodically (once a year) vacuum it and the area near it with a motor. Dust acts as a heat insulator, preventing freon from giving off heat, which forces the motor to work longer and harder, reducing its resource.
Also check condition of door seals. If the rubber becomes dry or dirty, wipe it with warm water and soap and replace it if necessary. A tight fit of the door is the key to a stable temperature and the absence of excess moisture in the system.
Is it possible to repair a refrigerator with a freon leak on your own?
Theoretically, it is possible if you have soldering skills, a vacuum pump, pressure gauges and a cylinder with freon. However, in practice, finding micro-leakage in a foamed casing is a daunting task. Most often, partial opening of the thermal insulation is required, which violates the aesthetics and requires subsequent sealing. Without experience, there is a high risk of permanently damaging the unit.
How long does it take the refrigerator to restore the temperature after defrosting?
Usually it takes from 2 to 6 hours to reach operating temperature, depending on the volume of the chambers and the ambient temperature in the room. If more than 8-10 hours have passed and the refrigerator still does not freeze (or the motor runs non-stop without achieving results), this is a sign of a malfunction.
Why does the refrigerator freeze only the freezer compartment?
This is a classic sign of a malfunction of the No Frost system (the fan does not work or the air supply channel is clogged) or the initial stage of a freon leak. In dual-compressor models, the problem may be in one of the circuits. It is also worth checking whether the food has blocked the outlet of cold air into the refrigerator compartment.
Is it dangerous to continue using the refrigerator if it hums but does not cool?
Yes, it is dangerous. The compressor, running idle or overloaded, quickly heats up. This can lead to insulation melting, short circuit and even fire. In addition, food in a warm chamber will quickly spoil. At the first signs of a lack of cold, it is better to turn off the device until the reasons are clarified.
What should you do if, after defrosting, the refrigerator started working, but after a day it stopped freezing again?
This is a sure sign of a “floating” malfunction, most likely associated with moisture in the system (ice blockage) or blockage. The water freezes in the bottleneck of the capillary, blocks the flow of freon, then thaws (when the compressor cools down or during defrosting), and the cycle repeats. Professional purging of the system and replacement of the filter are required.