The situation when the refrigerator works, but stops freezing in the upper compartment, is one of the most common and frightening for owners of household appliances. Unlike a complete failure of the unit, when the compressor is silent, here the motor can hum for hours, creating the illusion of normal operation, until the food in the freezer begins to melt. Understanding the physics of the cooling process helps to quickly identify the essence of the problem: cold air is heavier than warm air, and if circulation is disrupted or there is not enough refrigerant, the upper zone suffers first.
Modern models, be they two-chamber systems with a weeping evaporator or advanced units Total No Frosthave a single closed refrigerant circulation system. A violation in any unit - from the sensor to the compressor - instantly affects the temperature balance. Fault diagnosis requires consistent elimination of simple causes before calling a technician, since sometimes the problem lies in a simple overload or incorrect installation.
It is important not to ignore the first signs of an unstable work, such as the formation of an ice coat on only one wall or the appearance of extraneous sounds when the motor is running. Ignoring these signals can lead to compressor failure, the repair of which is often not economically feasible. In this article, we will examine in detail the mechanical and electrical causes of failure of the upper chamber and methods for eliminating them.
⚠️ Attention: If you hear a sharp bang followed by the smell of burnt wiring or a chemical smell, immediately unplug the device. Further operation in this condition may lead to a fire.
Problems with tightness and freon leakage
The most likely reason that the refrigerator does not freeze enough in the upper compartment is a simple refrigerant leak. Freon circulates in the system, which, evaporating, takes heat from the chambers. If the amount of gas decreases, there is simply not enough of it for the entire volume of the evaporator, and cooling occurs only at the beginning of the circuit, usually in the lower part of the freezer or on the rear wall.
Leaks often occur in places where tubes are soldered, in the foamed part of the body or through microcracks in the evaporator caused by corrosion or mechanical damage during defrosting. Leak symptoms are continuous operation of the compressor without shutting down, hot side walls (or, conversely, cold if the system does not work at all) and lack of cold in the upper compartment when the engine is running.
It is almost impossible to independently find the location of the leak and refill the system without special equipment, such as a leak detector and a vacuum pump. Attempts to simply add gas without fixing the hole in the circuit give only a temporary effect, after which the problem returns after a few weeks or months.
- 🔍 The compressor runs non-stop, trying to increase the temperature.
- ❄️ The freezer is cold only at the back wall or in the corner.
- 🌡️ The products in the upper compartment are soft, although the regulator is at maximum.
- 🔇 Complete absence of characteristic gurgling or hissing when the unit is operating.
If a leak is confirmed, the technician needs to not only find the hole, but also replace the filter drier, since it is saturated with moisture from the air that entered the system during depressurization. Re-filling freon without replacing the filter-drier is guaranteed to lead to clogging of the capillary tube in a short time. This is a critical technical nuance that is often missed by unqualified repairmen.
Malfunctions of the thermostat and temperature sensors
The thermostat (thermostat) is the “brain” that commands the compressor to turn on or off depending on the temperature in the chamber. In older models this is a mechanical device with a capillary tube, in modern ones it is an electronic sensor. If the thermostat fails and does not “feel” heat, it does not give a command to start the motor, and the refrigerator gradually defrosts.
In systems No Frost air sensors are responsible for the temperature regime. If such a sensor “lies” and shows the controller that the chamber is -20°C, although in fact it is 0°C, the compressor simply will not turn on. Diagnostics in this case requires testing the thermostat contacts with a multimeter at different temperatures.
Often the problem lies not in the sensor itself, but in oxidation of the contacts or a break in the wiring going to it. Vibration during compressor operation loosens connections over time. Replacing the thermostat is a simple procedure and is often performed by owners themselves if they have access to the part.
It is worth noting that in two-chamber refrigerators with one compressor, the thermostat usually controls the temperature in the upper chamber (refrigerator compartment). Therefore, its malfunction directly leads to loss of cold there, while the freezer can still maintain the temperature for some time by inertia.
Clogged capillary tube and problems with circulation
The capillary tube is a very thin copper pipeline that creates the necessary pressure for freon circulation. Due to its microscopic diameter, it becomes clogged with oil breakdown products or moisture, which turns into an ice plug. This phenomenon is called “hydraulic blockage.”
When there is a blockage, the compressor tries to push freon, hums, heats up, but circulation in the system is absent or very difficult. As a result, the cold does not reach the evaporator at the top of the chamber. A characteristic sign is that the condenser (grid at the back) may be only partially warm or completely cold.
Removing the blockage requires professional cleaning of the system with high-pressure nitrogen, replacement of the filter drier and vacuuming. At home, sometimes the method of “massaging” the tube or heating it helps, but these are temporary measures that do not solve the problem of contamination.
| Symptom | Probable cause | Nature of motor operation |
|---|---|---|
| It’s cold only at the bottom | Freon leak | Works without stopping |
| Heat in all chambers | Thermostat is faulty | Won't turn on at all |
| Buzzes and clicks | Capillary clogged | It turns on, after a while there is a click and silence |
| Ice only on one corner | Circulation disturbance | Works as usual |
Failure in the system No Frost (Defects in defrosting)
In refrigerators with a system No Frost the lack of cold in the upper chamber is often associated with ice freezing on the evaporator, which is hidden behind a plastic panel. If the defrosting system (heating element, timer, defrost sensor or fuse) does not work correctly, ice builds up and blocks the channels through which the fan should drive cold air into the chamber.
As a result, the fan hums, air circulates inside the technical compartment, but does not enter the refrigerator compartment. Outwardly, it looks like a working refrigerator with the lights on and the sound of the motor, but without cold. Often, before a complete failure, you can notice that the refrigerator has begun to freeze weaker or that sharp icicles have appeared on the back wall.
How to check the defrost system?
To check, you need to get to the evaporator. Remove the back panel in the freezer compartment. If there is a huge lump of ice, and the heating element underneath it is cold when the defrost is turned on, the problem is in the defrost circuit. If the heating element heats up, but the ice does not melt, it may be in poor contact or broken.
Diagnostics of defrost circuit elements requires testing each component with a multimeter for resistance. A burnt heating element or a “floating” defrost temperature sensor can be easily replaced. It is also important to check whether the defrost timer is stuck in cooling mode without switching to defrosting.
⚠️ Attention: Do not try to pick out the ice with a knife or screwdriver! Damage to the evaporator or fan tubes will lead to expensive repairs, which can cost as much as half a new refrigerator.
Mechanical damage and wear of seals
Sometimes the reason lies not in the “internals”, but in a violation of the tightness of the chamber itself. If the rubber seal on the upper chamber door becomes old, cracked or dirty, it no longer fits tightly to the body. Warm, moist air from the kitchen constantly enters the chamber.
The compressor tries to compensate for heat loss and works for wear, but due to the constant flow of heat, the temperature does not drop to the required values. This is especially noticeable in summer or in hot rooms. You can check the seal using a sheet of paper: hold it with the door and try to pull it out. If the sheet is removed easily without resistance, the seal is broken.
The door may also be skewed due to loose hinges or overweight shelves. Heavy food on the door can pull it down, creating a gap at the bottom or top. Adjusting the hinges often solves the problem without replacing parts.
- 🧹 Wash the seal thoroughly with warm water and soap to remove grease.
- 💡 Check for even fit around the entire perimeter of the door.
- 🔧 Adjust the legs of the refrigerator to ensure the correct tilt of the body back.
- 🚪 Make sure that the door is not skewed and closes tightly.
☑️ Diagnosis of the seal
When you need to call a specialist
There are a number of symptoms in which self-repair is not only useless, but also dangerous. If you hear that the compressor is trying to start, clicks and turns off (the thermal protection relay is working), this may mean an interturn short circuit in the motor windings or a critical blockage of the system.
Replacing a compressor is a complex technical operation that requires soldering copper tubes in an open flame, working with gas and evacuating the system. It is impossible to do this efficiently at home without professional tools. In addition, recycling old oil and freon requires compliance with environmental standards.
You should also contact a specialist if, after defrosting for 12-24 hours, the refrigerator does not start to freeze. This suggests that the problem is not an ice jam, but a hardware malfunction. Professional diagnostics are often paid, but it allows you to accurately estimate the cost of repairs and make an informed decision.
Remember that modern refrigerators are complex electronic and mechanical devices. An attempt at deep intervention without knowledge of circuit design can lead to the burning of the control board, the cost of which is up to 50% of the price of a new device.
Why is it warm in the upper chamber, but normal in the freezer?
This is a classic sign of a freon leak or a clogged capillary tube. There is only enough refrigerant for the first section of the evaporator (usually in the freezer), and it simply does not reach the upper compartment in the required volume. This may also be a sign of a malfunction of the damper that regulates the flow of cold air in dual-circuit systems.
Is it possible to operate a refrigerator if it does not freeze well?
For a short time - yes, but this cannot be done for a long time. The compressor operates non-stop, which leads to overheating and burnout of the windings. In addition, bacteria begin to multiply in the warm compartment, spoiling the food. It is better to temporarily reduce the load by moving the food to another place and start making repairs.
How long to defrost the refrigerator to check?
To completely defrost and equalize the pressure in the system, as well as to thaw possible ice jams in hidden places, the refrigerator should stand turned off with the doors open for at least 24 hours. A shorter defrosting may not yield results when diagnosing blockages.
Does the temperature in the room affect the operation of the refrigerator?
Yes, it does directly. If the room is too hot (above +30°C), the refrigerator may not be able to cope with the heat gain, especially if it is located close to the wall or heating devices. If it is too cold (below +10°C), the oil in the compressor thickens, and the thermostat may not turn on the motor, since it is “already cold.”