The situation when the upper part of the refrigerator suddenly stops working often takes you by surprise, especially if the food in the main chamber still remains fresh. The owner of the unit notices that the cold has disappeared from the shelves, the ice cream is defrosting, and the compressor is either humming without interruption, or, conversely, is silent. This is a classic symptom of a refrigerant circulation disorder or a malfunction in the temperature control system, requiring immediate intervention.
Before calling a technician, it is necessary to carry out an initial diagnosis, since in 15% of cases the problem lies in a banal violation of operating rules or electrical problems. Understanding the operating principle of your model - whether it Indesit with a crying evaporator or LG with a system No Frost - will help you quickly localize the fault and avoid unnecessary expenses on calling a specialist for basic settings.
In this article we will analyze in detail the mechanical and electrical reasons for the failure of the top cameras, consider the leak detection algorithm and explain why replacing the compressor yourself can be a fatal mistake for a household appliance. An in-depth analysis will allow you to make an informed decision on further actions.
Fundamental differences in the operation of single-compressor and two-compressor systems
The logic of troubleshooting directly depends on the design of the refrigeration unit. In models with one compressor, cold is supplied to the upper chamber (freezing or refrigerating, depending on the layout) through a single circuit. It is often used here freon, which, passing through the evaporator, cools the air, and a fan or natural convection distributes it among the volumes. If the top does not freeze, but the bottom works, this indicates a violation of heat exchange or (clogging) of the cold supply channel.
In two-compressor systems, such as many models Bosch or Siemens, each chamber has its own independent cooling circuit and its own engine. Here the situation is simpler: if the top does not work, then the problem is localized strictly in the contour of the upper chamber. This could be a failure of the second compressor, a leak in this particular circuit, or a breakdown of the thermostat responsible only for the upper compartment.
It is important to understand that in systems No Frost the upper part is often an area of intense evaporation. The air is forced through a hidden evaporator and supplied into the chamber through air ducts. If the top does not cool, but the fan is humming, the supply channel may be frozen or the defrost heating element, which should periodically melt the ice, has burned out.
⚠️ Attention: In two-compressor models, if one motor breaks down, the second one can continue to operate normally. Do not confuse this with a general electrical malfunction if the refrigerator is partially functioning.
For accurate diagnosis, you need to know the type of your refrigerant. Modern environmentally friendly gases, such as R600a (isobutane), have different pressure characteristics and require more careful handling during possible repairs than outdated ones R134a.
Mechanical faults: blockages and refrigerant leaks
One of the most common reasons why the upper part has stopped freezing is is clogged capillary tube. In the freon circulation system there is a narrow section - a capillary, where a sharp drop in pressure and temperature occurs. Over time, oil oxidation products or moisture can accumulate in this place, turning into an ice plug. Freon stops flowing into the evaporator of the upper chamber, and cooling stops, although the compressor continues to hum.
The second critical problem is refrigerant leak. If a micro-hole has formed in the circuit (often in the foamed part of the housing or on the welds of the evaporator), the gas gradually escapes out. The pressure in the system becomes insufficient for effective cooling of distant sections of the circuit, which is often the upper chamber. Signs of a leak are a hot condenser (grid at the back) and a complete absence of cold throughout the entire volume during long-term operation.
How to check the presence of freon without a pressure gauge?
If you do not have professional equipment, you can touch the back wall inside the refrigerator with your hand (if it is not hidden plastic) or evaporator. If freon is present, it should be cold or unevenly covered with frost. If the tubes are warm or at room temperature, there is no freon or it is all in the condenser due to a blockage.
The third mechanical factor is a malfunction filter drier. This element is responsible for removing moisture from the system. If it is clogged, the circulation of the refrigerant is disrupted, similar to a clogged capillary. In such cases, gurgling or hissing is often heard inside the housing, which indicates improper movement of the oil and gas mixture.
Repairing mechanical damage requires calling a technician with a vacuum pump and a filling station. It is almost impossible to fix a leak or clean the capillary on your own at home without the risk of permanently damaging the system.
Problems of the defrost system in No Frost refrigerators
In units with the system No Frost the upper chamber is closely connected to the evaporator unit hidden behind the back panel. If this panel is covered with a thick layer of ice (“fur coat”), and the fan is humming, but the cold is not coming out, then the cycle is broken. Ice blocks airflow (air flow), and cold masses simply cannot reach the products on the shelves. automatic defrosting. Ice blocks airflow, and cold masses simply cannot reach the products on the shelves.
Three main elements are responsible for the defrosting process: Defrost heating element, defrost thermostat (or temperature sensor) and timer (or electronic control module). If the heating element burns out, the ice does not melt. If the thermostat is stuck, it does not give the command to turn on the heating. As a result, in 2-3 weeks a monolithic block of ice grows, blocking the channels.
- ❄️ Symptom 1: The fan is louder than usual or makes a grinding noise because the blades touch the ice.
- ❄️ Symptom 2: Water appears at the bottom of the refrigerator or under the vegetable drawers, which does not have time to evaporate.
- ❄️ Symptom 3: The compressor works non-stop, trying to gain temperature, but the sensors show normal due to local hypothermia in the evaporator area.
For diagnostics, it is necessary to defrost the refrigerator completely (at least 24 hours with the doors open). If, after defrosting, the upper part began to work perfectly, but after 1-2 weeks the problem returned, the diagnosis of “malfunction of the defrost system” has been confirmed. It is necessary to test the heating element with a multimeter and check the resistance of the thermostat.
Electrical circuit malfunctions: thermostats and sensors
Electronics control the “brain” of the refrigerator. If the upper chamber is not cooling, but the compressor does not turn on at all or runs in too short cycles, the problem may be in thermostat (thermostat). In older models it is a mechanical “twist” with a bellows, in new ones it is an electronic sensor. If it “lies” and shows that there is already cold, the engine will not start.
In modern models with electronic control, each zone is responsible for its own temperature sensor. If the upper chamber sensor fails (resistance changes), the control module receives a false signal. For example, the sensor may show -20°C, when in reality it is +10°C. As a result, the controller does not give a command to cool this zone, although in the freezer (where there is another sensor) everything may be in order.
It is also worth checking solenoid valve (in some models). It shuts off the supply of freon to the refrigeration chamber circuit when the desired temperature is reached. If the valve is stuck closed, freon only circulates through the freezer and the top remains warm. This is a common problem in two-chamber refrigerators with one compressor.
| Component | Function | Symptom of failure | Method check |
|---|---|---|---|
| Thermostat | On/Off compressor | The compressor does not turn on or off | Contact dialing when temperature changes |
| Sensor (NTC) | Data transfer to the board | Incorrect temperature on the display, errors | Measuring resistance with a multimeter |
| Switching valve | Freon supply to the chamber | One chamber works, the other does not | Checking the voltage on the coil, clicks when turned on |
| Control board | Signal processing | Chaotic operation, lack of response to buttons | Visual inspection, measurement of output voltages |
Replacing sensors and thermostats is a procedure accessible to a home craftsman with basic skills. The main thing is to choose an analogue with identical characteristics, since even a small deviation in the parameters can lead to incorrect operation of the entire system.
Diagnostics of the compressor and start relay
The heart of the refrigerator - compressor. If it hums but does not start (you hear a click and the hum dies down), the problem may be with the start relay or the motor itself. In this case, there will be no cold anywhere, but sometimes inertia allows the lower chamber to maintain temperature for some time, creating the illusion that only the top is not working.
If the compressor works constantly without turning off, but the upper part does not freeze, this may indicate a loss performance. The piston group is worn out, and the compressor cannot create the necessary pressure to pump freon through the entire circuit. Gas circulates, but only at the beginning of the system (usually the freezer), without reaching the upper compartments.
☑️ Primary check of the compressor
Another nuance - starting relay. If it is faulty, the compressor may not start at all or may start jerkily. In some dual-compressor models, the relay may be separate for each motor. Checking the relay consists of visually inspecting the contacts and checking the continuity of the windings.
The influence of external factors and operating rules
The reason is not always a breakdown. Often, users themselves create conditions under which the upper part ceases to perform its functions. Dense loading blocks the ventilation holes with products. Cold air physically cannot circulate if the boxes are filled to capacity and rest against the back wall.
Also critical door tightness. If the top door seal is worn out, dirty, or the door itself is warped, warm, moist air constantly enters. The defrosting system does not have time to remove moisture, and an ice crust forms, blocking heat exchange. You can check the seal with a simple test with a sheet of paper: hold it with the door and try to pull it out - it should come out with force along the entire perimeter.
⚠️ Attention: Installing the refrigerator close to the wall or in a niche without a gap disrupts the heat transfer of the condenser. The compressor overheats and goes into protection, stopping cooling the chambers.
The temperature in the room also matters. If the refrigerator is placed on an unheated loggia or next to a radiator, where the temperature is below +10°C or above +35°C, the refrigerant may not evaporate or condense correctly. In such conditions, the upper chamber often fails first.
FAQ: Frequently asked questions
Why did the refrigerator work after defrosting, but after a week stopped freezing the top again?
This is a classic sign of a malfunction of the defrost system (the heating element, thermostat or timer burned out). Defrosting temporarily removes the ice plug, but since the automatic melting mechanism does not work, the ice builds up again, blocking the channels.
Is it possible to operate the refrigerator if the upper chamber does not work?
For a short time - yes, if the food in the lower chamber does not spoil. However, prolonged operation in this mode is harmful to the compressor, which can work without stopping, trying to compensate for heat loss. In addition, melting ice can cause water to leak onto the floor.
How much does the repair cost if you need to replace the compressor?
The cost consists of the price of a new unit, the work of a technician, evacuation of the system and refilling with freon. This is one of the most expensive types of repairs, often amounting to 50-60% of the cost of a new refrigerator.
How to understand that there has been a freon leak, and not just a blockage?
If there is a leak, the condenser (grid at the back) will be cold or barely warm, and if there is a blockage, it will be very hot. Also, if there is a leak, the compressor may work longer than usual, but not gain temperature anywhere, while if there is a blockage, one part of the system will overheat and the other will freeze.
Does the position of the transportation bolts affect the operation of the refrigerator?
Yes. If, when installing a new refrigerator, the transport bolts on the compressor were not unscrewed (if they are provided for in the design), vibration and noise will be colossal, and operating efficiency will be reduced. However, this rarely affects the lack of cold in the upper part, rather it affects the overall resource.