The situation when the refrigerator compressor hums without interruption is familiar to many owners of household appliances. This is not just an annoying noise that interferes with restful sleep, but also an alarming signal that cooling system it is working in emergency mode. If timely measures are not taken, the engine may burn out, and the food in the chamber may deteriorate due to a violation of the temperature regime.
In most cases, the reason lies in banal operating errors or a loose door fit, but sometimes the problem requires the intervention of a specialist. Understanding the principles of operation compressor-condensing unit will help you quickly determine the source of the malfunction and avoid costly repairs. Let's look at why the equipment behaves incorrectly.
The first thing to do is to evaluate the nature of the motor. Does it hum smoothly or intermittently? Does the back of the case get hot? Answers to these questions will help narrow down the scope of troubleshooting.
Influence of external factors and operating conditions
Before opening the technical compartment or calling a technician, it is necessary to exclude the influence of the external environment. Often compressor overheating caused by a banal violation of the rules for installing the device. If the refrigerator is standing close to the wall or in a niche without proper clearance for ventilation, heat transfer is disrupted and the motor is forced to wear out.
It is also worth checking the temperature in the room. In hot summer weather, when the temperature in the room is above 30-35 degrees, it is physically more difficult for the refrigerator to remove heat. In such conditions, it can work almost non-stop, trying to maintain the set parameters inside the chambers.
⚠️ Attention: Do not try to speed up cooling by opening the door wide or setting the minimum temperature in the freezer. This will create an additional load on thermostat and will only worsen the situation.
Another important aspect is the tightness of the circuit. If the rubber seal on the door is worn out, dirty or deformed, warm air constantly enters the chamber. Sensors detect an increase in temperature and give the command to the motor not to turn off.
Checking the thermostat and temperature sensors
One of the most common reasons for continuous operation is failure of the thermostat (thermostat). This element is responsible for turning the compressor on and off depending on the temperature inside the chamber. If its contacts are “stuck” in the “on” position or the sensor transmits incorrect readings to the control board, the refrigerator will work constantly.
In modern models with electronic control, defrost sensor or a temperature sensor is responsible for control. Its breakdown often results in the system “not seeing” the achieved cold and not stopping the cooling cycle. Diagnostics of such elements requires a multimeter and certain knowledge of electrical engineering.
Symptoms of a malfunctioning thermostat often manifest themselves in the absence of characteristic clicks when switching from cooling mode to rest mode. If you do not hear a shutdown sound after a long period of operation, most likely the problem is in the control circuit.
How to check a thermostat with a multimeter?
To check, you need to remove the thermostat, set the multimeter to the dial mode and connect the probes to the sensor contacts. At room temperature the chain should ring. If you put the sensor in the freezer for 15 minutes, the circuit should break (the sound will stop). If this does not happen, the part is faulty.
Problems with the refrigerant and system tightness
A more serious problem is leakage freon (of the refrigerant). It would seem that if there is little gas, the refrigerator should work worse, but the opposite happens: the compressor hums non-stop, trying to gain temperature, but due to a lack of working fluid this does not happen. As a result, the motor overheats, and the chamber is warm.
Leaks can occur at the soldering points of the tubes, in the evaporator, or even in the foamed part of the housing. It is difficult to determine a leak visually; often this is indicated only by metal corrosion at the junction of the tubes or a characteristic hissing sound when the circuit is damaged.
If an “ice jam” has formed in the system (moisture freezing in the capillary tube), the circulation of freon is also disrupted. The compressor runs, but the refrigerant does not circulate through the circuit and no cooling occurs. This requires a professional charging and vacuuming system.
Faulty compressor and start relay
The very "heart" of the refrigerator - compressor - can also be the source of the problem. If the motor is worn out, its performance decreases. It works at full power, but cannot create the necessary pressure in the system. In such cases, often only replacing the unit helps.
Deserves special attention start-up protection relay. This small element is responsible for starting the engine and protecting it from overloads. If the relay is faulty, it may not open the circuit after starting, which is why the motor continues to run even when it is not necessary, or hums, but does not start.
Signs of problems with the compressor are often accompanied by strong heating of the motor housing (up to 80-90 degrees) and a specific smell of burnt insulation. If you smell such a smell, immediately disconnect the device from the network to avoid a fire.
☑️ Compressor diagnostics
Failure of the electronic control module
In new generation refrigerators with a system No Frost and electronic control, the control module is responsible for all processes. Malfunctions in its operation, power surges in the network or oxidation of contacts can lead to the fact that the “brains” of the device stop sending a signal to turn off the compressor.
Often the problem lies in burnt triacs or relays on the board. Visually, this may look like blackening of the elements or swelling of the capacitors. Repairing a module requires high qualifications and soldering equipment.
Sometimes a complete reset (reboot) helps. To do this, you need to disconnect the refrigerator from the power supply for 15-20 minutes. If after switching on the operating mode returns to normal, it means a software failure has occurred. If not, diagnostics of the board is required.
Table: Symptoms and probable causes
To quickly navigate through the problem, use the summary table of symptoms. It will help you understand which direction to go when troubleshooting.
| Symptom | Probable cause | Difficulty of repair |
|---|---|---|
| The compressor hums, but does not cool | Leakage freon or system blockage | High (requires a master) |
| The motor runs non-stop, the chamber is cold | The thermostat or sensor is faulty | Medium (you can do it yourself) |
| Extreme heating of the housing at the rear | Poor ventilation or compressor wear | Low / Medium |
| Clicks and attempts to start | Faulty start relay | Low (part replacement) |
When you need to call a technician
Not all breakdowns can be repaired yourself. If you checked the seals, made sure there was normal ventilation and rebooting did not help, most likely the problem is deeper. Refilling with freon, soldering tubes and repairing the electronic module require special equipment and licenses for working with refrigerants.
Also, you should not take risks if the refrigerator is under warranty. Any tampering with sealed components (compressor, capillary tube) will result in loss of the manufacturer's warranty. In this case, the only correct way is to contact an authorized service center.
⚠️ Attention: Working with refrigerants requires caution. Some types of freon emit toxic substances when in contact with an open flame. Do not try to solder tubes yourself without proper preparation.
If you decide to call a specialist, prepare a model of the refrigerator and describe the symptoms as accurately as possible. This will allow the technician to take the necessary spare parts with him and reduce repair time.
Prevention of continuous operation
To extend the life of your refrigerator, it is important to follow simple operating rules. Defrost your equipment regularly (if it is not No Frost), wash the drainage holes and check the cleanliness of the condenser at the back. Dust on the radiator grille is a common cause of overheating.
Monitor the room temperature. If the kitchen is located on the sunny side, during hot hours try to ventilate the room or use a hood to reduce the overall air temperature around the appliance.
Timely replacement of worn parts, such as rubber seals, will cost less than repairing a compressor that has burned out from overload. Do not ignore the first signs of unstable operation.
How often should you wash the capacitor?
Ideally - every 6 months. If you have pets, hair can clog the grill much faster, so check the condition of the radiator once a quarter.
Why does the refrigerator hum but not freeze after defrosting?
Most often this is a sign of a freon leak or the formation of an ice plug in the capillary. When defrosting is complete, the ice melts, but the system does not start correctly due to circulation problems. You need to call a technician to find a leak and refill it.
Is it possible to operate the refrigerator if it does not turn off?
For a short time - yes, so that the food does not disappear. But long-term operation without a break (more than 24 hours) will lead to overheating and failure of the compressor. It is necessary to find the reason or temporarily turn off the device.
Does the amount of food affect the operating time?
Yes, a full refrigerator keeps the cold longer, but it also takes longer to cool after loading warm products. However, an empty refrigerator with a broken seal will also work constantly. It is important not to overload the chambers by blocking the airflow.
What to do if the situation has not changed after replacing the thermostat?
This means that the problem is not in the sensor. Perhaps the compressor itself is faulty, there is a freon leak, or a problem in the electronic module. Further diagnostics using a pressure manifold are necessary.
Is it normal for the refrigerator to run for a long time in the summer?
Yes, in hot weather the compressor operating time increases and the standby time is reduced. But it should still turn off periodically. If it does not turn off at all, this is a malfunction.