The situation when your refrigerator begins to behaves uncharacteristically and always causes anxiety. You notice that the unit hums much longer than expected, trying to reach the set temperature, and then there is a long silence, during which the food in the chamber may begin to deteriorate. This behavior often indicates that the cooling system is operating intermittently or is overloaded. In modern models with a system No Frost or drip defrosting, the on and off cycles are strictly regulated electronically, and deviations from the norm require immediate attention.
Ignoring symptoms can lead to failure of expensive components, such as compressor or the control board. Understanding the reasons why equipment works for a long time and rarely turns on will help you save on repairs or prevent complete loss of products. In this article, we will analyze in detail the mechanical and electrical malfunctions that cause similar symptoms.
⚠️ Attention: If you hear clicking sounds when you try to start or smell a burning smell, immediately disconnect the device from the power supply. Further operation in this mode may lead to a fire in the wiring or a jam in the motor.
Primary diagnosis often depends on exactly how the problem manifests itself: whether the refrigerator freezes weakly or, conversely, freezes food before a long period of inactivity. Electronic control module may read the readings erroneously sensors, causing the unit to operate in emergency mode. It is important not to panic, but to consistently check the main components.
Malfunctions of the thermostat and temperature sensors
One of the most common reasons why refrigerator it takes a long time to gain temperature and rarely turns off is the failure of the thermostat. In older models, this is a mechanical device that physically opens the circuit when cold temperatures are reached. If its sensitivity has dulled or the capillary tube has lost its tightness, the compressor will work until the bitter end until the thermal protection relay is triggered, after which there will be a long pause.
In modern electronically controlled units, this process is responsible temperature sensors (thermistors). They are located in the evaporator, refrigerator and freezer compartments. If one of them produces incorrect data or has a “floating” contact, the refrigerator brain does not receive a signal that the desired temperature has been reached. As a result, the cooling cycle is delayed, and the subsequent rest may be unreasonably long due to errors in the logic of the controller.
- ❄️ Shift in sensor calibration leads to the fact that the refrigerator “thinks” that the chamber is warmer than it actually is.
- 🔌 Oxidation of contacts in the thermostat connector causes an intermittent signal that disrupts the operating algorithms.
- 🌡️ Damage to the capillary tube of a mechanical thermostat leads to leakage of freon filler and loss of sensitivity.
Thermostat diagnostics often require testing the contacts with a multimeter at different temperatures. If you are not confident in your skills in working with electrical appliances, it is better to entrust this task to a specialist, since incorrect installation can lead to cyclic on-off switching every few minutes, which is detrimental to the engine.
⚠️ Attention: When replacing temperature sensors in systems No Frost it is extremely important not to damage the fragile wires and correctly fit the new sensor into the standard socket, otherwise the readings will be incorrect.
Problems with the start relay and compressor
The heart of any refrigerator is compressor. If it works with overload, this immediately affects the duration of the cycles. Often the problem lies in the start-up relay. This small element is responsible for starting the engine and protecting it from overheating. When the relay wears out, it can keep the circuit closed for a long time or, conversely, prevent the engine from starting the first time, creating the effect of “long work” with breaks for cooling.
Wear of the compressor itself also leads to a drop in performance. The piston group wears out, the valves lose their tightness, and the pressure in the system drops. The motor is forced to work almost non-stop to compensate for the loss of cold, but due to overheating it often goes into protection, creating long pauses. In such cases, the refrigerator hums, but gives little cold.
You can check the operation of the compressor by placing your hand on its body (be careful, it may be hot). If it is red hot or to temperatures that cannot be touched, then it is operating in emergency mode. It is also worth paying attention to the current consumption: if it is significantly higher than the rated current indicated on the nameplate, the problem is definitely in the electrical part of the motor or relay.
- 🔥 Overheating of the compressor windings due to insufficient ventilation or dust behind the unit.
- 🔨 Mechanical knocking or hum indicates wear of the bearings or internal suspension motor.
- ⚡ Frequent clicks of the relay indicate an attempt to start and instantaneous shutdown of the protection.
Refrigerant leakage and blockage capillary system
The most serious technical reason why refrigerator works for a long time and does not turn off is a freon leak or a clogged capillary tube. The refrigerant is the working fluid that transfers heat from the chambers to the outside. If its amount in the system decreases due to microcracks in the circuit or corrosion, the efficiency of heat transfer decreases. The unit is working hard, trying to achieve the set parameters, but physically cannot do this quickly.
Clogging of the capillary tube often occurs due to moisture entering the system or oil breakdown products. At the point of narrowing, an ice plug or mud mass forms, blocking circulation. The pressure on the suction side drops, the compressor operates in a vacuum, which also leads to overheating and long operating cycles. In this case, the condenser (grid at the back) may remain only partially cold or warm.
Diagnosing a leak or blockage at home is difficult, since a pressure gauge manifold station and the skills of a roller are required. However, an indirect sign may be swelling of the side walls of the refrigerator (where the circuit is foamed) or the appearance of oily spots under the unit.
| Symptom | Probable cause | Nature of compressor operation |
|---|---|---|
| The refrigerator is warm, the compressor hot | Freon leak | Works continuously or with short breaks |
| The freezer freezes, the refrigerator compartment does not | Capillary clogged or fan No Frost | Long cycles operation |
| Severe freezing of the rear wall | Faulty defrost or sensors | Irregular cycles dependent on ice |
| The compressor is cold, but hums | Not the motor (relay/capacitor) starts | Short switching on with clicks |
⚠️ Attention: Independent refilling of the refrigerator with freon without evacuating the system and replacing the filter-drier is strictly prohibited. Residual moisture in the system will lead to a new blockage in a few days.
Failure in the defrost system (for No Frost models)
In refrigerators with the system No Frost the serviceability of the defrost system is critically important. If the defrost heating element, timer or defrost sensor fails, the evaporator becomes coated with ice. This ice blocks the air flow and the cold stops flowing into the chambers. Temperature sensors detect heat and instruct the compressor to run longer. As a result, the engine hums for hours, trying to break through the ice jam, and then goes into a long rest.
You can check for the presence of ice by reaching the evaporator (usually the back wall of the freezer behind the plastic panel). If you can see a solid piece of ice hiding the radiator fins, the problem is in the defrost cycle. In this case, the refrigerator can work for days, since ice is an excellent heat insulator and interferes with cooling.
How to defrost a refrigerator correctly?
Disconnect the device from the network for at least 12-24 hours. Keep doors open. Do not use a hairdryer or hot water to speed up the process - this can damage the plastic and lead to cracks in the evaporator.
A frequent breakdown is the defrost heating element burning out. It just stops heating and the ice doesn't melt. Less often, the defrost sensor fails, which “does not see” that the ice has melted and does not allow heating to start, or vice versa - does not allow cooling to start. It is also worth checking the drainage hole: if it is clogged, water flows to the floor or freezes below, creating additional problems.
- 💡 A burnt-out defrost heating element is the most common cause of the formation of an ice lump.
- ⏱️ A faulty defrost timer does not switch the "cooling/defrosting" modes on time.
- 💧 Clogged drainage leads to leaks inside the housing and freezing of channels.
Environmental influences and improper operation
The cause is not always a breakdown. Sometimes refrigerator works for a long time due to external factors. High ambient temperature in the room (for example, in the summer in a kitchen without air conditioning or near a stove) causes the heat exchanger to work less efficiently. The condenser does not have time to cool down, the pressure in the system increases, and the compressor is forced to work longer to release heat.
Poor ventilation is another scourge of modern built-in refrigerators. If the unit is tightly surrounded by furniture and the gap for air circulation is minimal, hot air from the radiator circulates in a circle, heating the refrigerator itself. This leads to increased operating time and long pauses until the motor cools down enough for the next start.
☑️ Checking the operating conditions
It is also worth considering the loading of cameras. If you put a large amount of warm food in the refrigerator, it will work in intensive mode for several hours. This is fine. However, if the door does not fit tightly due to a dirty seal or a skewed door, the cold will constantly escape, forcing the equipment to work almost non-stop.
⚠️ Attention: Technical characteristics of refrigerators may vary depending on the climate class. Make sure that your model is designed to work at the temperature that prevails in your room (for example, class SN is not intended for hot kitchens).
Diagnostics and procedure for action in case of malfunction
If you encounter the problem described, do not rush to call a technician right away. Start with simple steps. Complete defrosting of the refrigerator during the day often helps eliminate false sensor readings and remove ice plugs in the channels. After turning on, let the unit run empty for 2-3 hours and evaluate the dynamics.
Check the tightness of the door. A sheet of paper clamped around the perimeter of the door should not be easily pulled out. If the seal is worn out, replacing it will solve the problem of constant operation. Also inspect the back of the condenser: a layer of dust several millimeters thick reduces heat transfer by 20–30%, which directly affects the duration of the cycles.
In cases where simple measures do not help, professional diagnostics with tools are required. The technician will check the pressure in the system, the current consumption of the compressor and the serviceability of the electronics. Repairs can range from replacing a cheap sensor to complex overcooking of the circuit.
Why does the refrigerator not turn on for a long time after defrosting?
This is normal. After complete defrosting, it takes time for the thermostat or sensor to detect an increase in the temperature inside the chambers to a level where it needs to be turned on. In an empty refrigerator, this process can take from 2 to 6 hours. Don’t panic if the motor is silent during the first hours.
Is it possible to operate a refrigerator if it has been running for a long time?
For a short time - yes, but this leads to increased energy consumption and wear on the compressor. If the cause is a freon leak, the motor may burn out due to overheating, since the returning gas must cool the windings. Long-term operation in emergency mode is not economically feasible.
How to understand that the compressor has burned out?
If, when turned on, you hear a beep, then a click, and nothing else happens, and the motor housing itself remains cold, the winding is probably burned out or the motor is jammed. Another sign may be that the machine in the panel is knocked out when trying to start.