The situation when you open the refrigerator door and it’s warm inside always causes panic, especially if perishable foods are stored in the compartments. The system No Frost, designed to save us from manual defrosting, is itself a complex mechanism where the failure of one element stops the operation of the entire circuit. Unlike drip systems, here the circulation of cold air is forced, and if this flow stops, the temperature quickly equalizes to room temperature.
The first thing to do is to assess the scale of the problem: only the refrigerator compartment, freezer or heat in the entire unit does not work. Users often notice that the compressor hums continuously, trying to increase the temperature, but there is no effect. In other cases, the equipment may not make engine operating sounds at all, which indicates problems with the electrical circuit or trigger mechanism.
Before calling a technician, it is worth conducting an initial diagnosis to rule out trivial causes. Check the tightness of the rubber seals, as even a small gap leads to a constant flow of warm air. Also make sure that the operating mode has not been accidentally changed to “holiday” or minimum cooling in the electronic control settings.
Malfunctions of the defrost and evaporator system
The most common reason why Samsung refrigerator or LG stops freezing is due to automatic defrost system. In No Frost units, the evaporator is hidden behind a plastic panel in the freezer, and over time a coat of ice builds up on it. If the defrost system fails, ice blocks the ventilation ducts, and cold air simply cannot flow into the main chamber.
Three key elements are involved in this process: the defrost timer (or electronic module), the heating element (heater) and the thermal fuse. When one of them fails, the defrost cycle does not start or is interrupted prematurely. You may notice that the back wall of the freezer is covered with a thick layer of frost or, conversely, appears dry, although the compressor is running.
⚠️ Attention: If you plan to defrost the refrigerator manually for inspection, do not use sharp objects to chip ice from the evaporator. Damage to the evaporator tubes will lead to an immediate release of refrigerant and expensive repairs.
Diagnostics of the heating element requires testing with a multimeter, since it is impossible to visually determine a broken filament without disassembling the unit. Often, it is the thermal fuse that protects against overheating that blows, breaking the circuit when critical temperatures are reached. Replacing these elements usually solves the problem if the wiring itself is not damaged.
How to check the defrost heating element?
To check the heating element, you need to gain access to the evaporator by removing the back panel in the freezer. Disconnect the wires from the heater and set the multimeter to resistance measurement mode. If the device shows infinity (break), the heating element is faulty and requires replacement. Normal resistance is usually from 200 to 400 Ohms.
Problems with the compressor and start relay
The compressor is the heart of the refrigerator, and if it does not start or does not work correctly, there will be no cooling in any of the chambers. You may hear a distinctive click, followed by a buzzing sound that lasts a few seconds, and then another click and silence. This is a classic symptom of a malfunction starting relay or the windings of the engine itself.
The starting relay is responsible for starting the engine and turning off the starting winding after gaining speed. Inside it there is a posistor or coil, which degrades over time. If the relay is stuck in the off position, the compressor will not receive the necessary impulse to start. In some models, for example Indesit or Atlant, the relay can be easily removed and changed without special tools.
A more serious situation occurs when the compressor hums constantly and gets very hot, but does not start. This may indicate an interturn short circuit in the windings or jamming of the piston group. In this case, the unit consumes increased current, and the thermal protection is triggered, opening the circuit until the engine cools down.
Sometimes the cause of failure is low voltage in the network. Modern inverter compressors are sensitive to changes and can go into protection when the voltage drops below 190 Volts. Check the voltage in the outlet using a tester before you sin on the equipment.
Refrigerant leak and capillary system clogged
If the compressor works non-stop, trying to reach the set temperature, but the chambers are warm, there is a high probability of a freon leak. The refrigerant circulates in a closed circuit, and a violation of its tightness leads to a decrease in pressure and loss of cooling capacity. It is difficult to notice a leak visually, since the gas is colorless and odorless.
Often leaks occur in places where tubes are soldered or in the foamed part of the body, where the metal has corroded from moisture. You may notice swelling on the sides of the refrigerator or oily spots around the compressor. Oil flows out along with the gas and is a sure indicator of the location of depressurization.
Clogged capillary tube is another reason why freon cannot circulate. An ice plug or blockage with oil breakdown products forms in the system. In this case, the condenser (grid at the back) can be hot only at the beginning, and the rest of the part remains cold.
| Symptom | Probable cause | Nature of compressor operation |
|---|---|---|
| Heat in the entire refrigerator | Freon leak | Works constantly or does not turn on |
| The freezer freezes, the refrigerator compartment does not | Clogged or faulty damper | Operates normally |
| Clicks and humming | Malfunction of the starting relay | Short-term attempts to start |
| Frost only at the channel entrance | No Frost system malfunction | Works without breaks |
To eliminate a leak, a search for the location of the damage is required, often using pressurized nitrogen, followed by soldering and charging with new refrigerant. It is impossible to carry out this procedure independently without a vacuum pump and scales for dosing gas.
Fan and air damper malfunctions
In system refrigerators No Frost a fan located in the freezer is responsible for air circulation. If it stops spinning, cold air remains in the freezer and the refrigerator compartment becomes warm. The reason for the stop may be freezing of the blades or failure of the fan motor.
Often the fan is blocked by ice that freezes on the shaft due to a broken door seal or a malfunction of the defrost system. In this case, you may hear some noise, crackling or humming coming from deep inside the freezer. The blades, hitting the ice, stop rotating.
In models with two cooling circuits, the air damper (damper) is responsible for the distribution of air flows. It opens and closes at the command of the thermostat, releasing cold into the upper chamber. If the damper mechanism is stuck in the closed position or the drive motor is burned out, the refrigerator compartment will remain without cooling.
⚠️ Attention: Before checking the fan, be sure to unplug the refrigerator. Rotating blades can cause injury, and moisture getting on open wiring during defrosting is dangerous due to electric shock.
Checking the fan is simple: with the freezer door open (and the door sensor clamped, if there is one), the fan should work. If it is silent when voltage is applied, the part requires replacement. It is also worth checking whether the wires going to the engine are frayed.
Failures in the operation of sensors and electronic module
Modern refrigerators, such as Bosch or Haierare controlled by complex electronics that receive data from many temperature sensors. If the sensor in the refrigerator compartment “lies” and shows that it is already cold there, the control module will not give a command to cool, even if it is hot inside.
Temperature sensors are thermistors, the resistance of which changes depending on the heating. Over time, their characteristics “float” and they begin to transmit incorrect data to the control board. This leads to chaotic switching on and off of the compressor or complete system failure.
The electronic control module is the “brain” of the refrigerator. Power surges in the network can damage elements on the board, which will lead to incorrect control of all nodes. In some cases, the module can be reflashed or repaired, but often a complete replacement is required.
☑️ Electronics diagnostics
Sometimes the problem lies not in the board itself, but in the oxidized contacts of the connectors. Moisture entering the housing can cause corrosion of the contacts, which disrupts the transmission of signals between the sensors and the module. Careful inspection of the connectors and their cleaning can restore operation.
The influence of operating mode and external factors
The reason for the lack of cold is not always a breakdown. Sometimes the user himself sets the wrong settings. For example, the activated “Super Freeze” mode in some models can work cyclically, or the temperature is set to the minimum value, which is perceived as a lack of cold.
The location of the refrigerator also plays a role. If the equipment is located close to the wall or in a niche without gaps for ventilation, the condenser does not have time to release heat. This causes the compressor to overheat and reduce cooling efficiency. The minimum gap at the back should be at least 5-7 cm.
Loading the refrigerator with food affects the cooling capacity. If you have just placed a large amount of warm food inside, the system will take time (up to 24 hours) to stabilize the temperature. During this period, the compressor can work without interruption.
It is also worth considering seasonality. In winter, in an unheated room, the oil in the compressor may thicken, making it difficult to start. In the summer, in extreme heat, the equipment may not cope with the heat flow if the room is not ventilated.
Frequently asked questions and answers (FAQ)
Why does the refrigerator hum, but does not freeze after defrosting?
If you defrosted the refrigerator for less than 8-10 hours, there could be ice left in the system, which blocks channels. It is also possible that during defrosting you damaged the evaporator tube, which led to a freon leak. Let the unit stand unplugged for a day so that the moisture completely evaporates.
Is it possible to use a refrigerator if it does not freeze well?
It is not recommended to operate equipment with a malfunction. A compressor operating non-stop if there is a freon leak or blockage will quickly overheat and burn out. In addition, bacteria actively multiply in a warm environment, which is dangerous for products.
How to understand that the compressor has burned out?
The main sign is that the compressor is hot, emits a loud hum or clicks, but does not start, or starts for a couple of seconds and stalls. It can also knock out the automatic switch in the panel when the refrigerator is turned on.
Why is it warm in the refrigerator compartment, but ice in the freezer?
This is a classic sign of a malfunction of the No Frost system: either the fan does not work, or the air supply channels are clogged with ice, or the air damper does not open. Cold is produced, but does not enter the upper compartment.