The situation when a refrigeration unit stops performing its functions always takes you by surprise. The food begins to deteriorate, the ice melts, and the inside of the chamber becomes warm. However, if you notice that The refrigerator does not heat in the evaporator area or on the rear outer wall, this may indicate a specific problem with the defrost system or refrigerant circulation. Understanding the principles of operation of the compressor and the freon circuit will help you quickly navigate the problem.
In normal operation, the motor-compressor pumps hot gas into the condenser, which then cools as it passes through the tubes. If this process is disrupted, heat is not released where it should. Owners often confuse the lack of heating of the condenser with a breakdown, although in some energy saving modes this may be the norm. However, persistently ignoring signs of malfunction leads to spoilage of food and complex repairs.
In this article we will look in detail at why the rear grill stops heating, what to do if the freezer compartment does not freeze, but the refrigerator compartment, on the contrary, defrosts. We will consider both simple causes that can be eliminated on your own, as well as complex technical faults that require the intervention of a specialist. It is important to act consistently and not make mistakes when diagnosing the electrical part.
The principle of operation of the defrost and condensation system
To understand why the unit behaves strangely, you need to know the basics of thermodynamics inside the cabinet. No Frost System or drip systems depend on cyclic heating and cooling. In models with full automatic defrosting, a heating element (thermoelectric heater) is responsible for this. If it does not turn on, ice freezes on the evaporator, blocking airflow.
The heat exchanger located at the back of the housing (black grille) should be warm or even hot in good condition. This is a normal physical reaction of compressed freon. If you touch the grill, and it is cold, it means that the compressor is not working or there is no pressure in the system. Indesit refrigerators and Atlant they often suffer from clogged capillary tube, which disrupts the entire cycle.
⚠️ Attention: Never try pick off the ice from the evaporator with a knife or sharp objects. Damage to the evaporator tubes will lead to an immediate release of refrigerant and expensive repairs with replacement of the entire sealed system.
Refrigerant circulation is a closed process. The gas is compressed, heated, releases heat to the environment through a condenser, then expands and cools sharply in the evaporator. If at some stage the chain is broken, no heat is released. Diagnostics begins with checking whether the compressor is working and whether the condenser is heating up.
Diagnostics of compressor and start relay faults
The first element that needs to be checked is the heart of the refrigerator - the compressor. If it doesn't start, then there's nothing to heat. Often the problem lies not in the motor itself, but in starting relay. This is a small part that provides the starting impulse. If the relay is burned out, the compressor may hum, twitch, but not start.
Checking the relay is carried out visually and with a continuity tester. There should be no carbon deposits inside, and the contacts should close at a certain position. In some cases, replacing the relay with a similar one helps. However, if the compressor itself is jammed, no relay will help - the entire motor will need to be replaced.
It is also worth paying attention to the thermostat. If it is “stuck” in the “off” position, the compressor simply will not receive a command to start. In modern models with electronic control, instead of a mechanical regulator, there is temperature sensorwhich can also fail.
☑️ Compressor diagnostics
It is important to distinguish between a noisy compressor and the knocking or humming of a faulty one. If the unit turns on for a couple of seconds and turns off with a click, this is a classic sign of a problem with the starter or a winding break.
Problems with the defrosting system in No Frost refrigerators
In systems No Frost the defrost timer and the evaporator heating element are critically important. If the timer does not switch modes, the refrigerator only works for cooling, without starting the defrost cycle. Ice builds up on the fan and evaporator, blocking the access of cold air to the chamber. As a result, it is warm in the refrigerator compartment, although the freezer may still be working.
The defrost heating element is a nichrome spiral that burns out over time. You can check its integrity with a multimeter. If the resistance is infinitely high, then the heating element is broken. Replacing the heating element is an accessible procedure, but requires partial disassembly of the back wall of the freezer.
- 🔥 The heating element does not heat - the coil is burnt out or the contacts are oxidized.
- ⏱️ The defrost timer is jammed - does not switch the “cooling/defrosting” modes.
- ❄️ The defrost sensor is faulty - it does not give a signal about the need for heating.
- 💨 The blower fan is frozen - the ice has blocked the blades.
⚠️ Attention: When replacing the heating element, be sure to disconnect the refrigerator from the network. Working with energized heating elements is deadly. Also check the condition of the wiring going to the heating element; it often melts.
A symptom of a malfunction in the defrost system is often water under the refrigerator or on the kitchen floor. This melts the ice, which does not have time to evaporate in the compressor tray due to its large volume. In such cases, Bosch refrigerators i Samsung can display error codes on the display.
Freon leak and capillary tube clogged
If the compressor runs constantly, do not when turning off, it hums, but there is no cold, and the condenser (grid at the back) is cold or warm only at the outlet of the compressor - probably freon leak. The refrigerant evaporates through microcracks in the circuit. Without freon, heat exchange does not occur, and the refrigerator stops freezing.
Clogged capillary tube is the second common cause. Oil and freon circulate in the system. Over time, the oil can thicken or moisture can enter, which turns into an ice block. This blocks the flow of gas. The compressor tries to push through the plug, hums, but there is no circulation.
| Symptom | Possible cause | Nature of heating of the condenser | Actions |
|---|---|---|---|
| Compressor silent | No current, relay burned out | Cold | Measure voltage, replace relay |
| Buzzing, does not freeze | Clogged or leaking | Warm only at the motor | Call a technician, vacuum |
| Works jerkily | The compressor is jammed | Does not heat up | Replacement compressor |
| It freezes slightly | Lack of freon | Partially warm | Searching for leaks, refilling |
It is difficult to diagnose a leak on your own. Often it occurs in the foamed part of the body (inner circuit). In such cases, repairs are not economically feasible. If the leak is in a visible part (for example, in the locker - a tube running around the perimeter of the door to prevent condensation), repair is possible.
Is it possible to fill the refrigerator with freon yourself?
Self-refueling is highly not recommended. Special equipment is required: a vacuum pump, a pressure gauge station, scales for accurate dosing. In addition, you need to know the type of freon (R134a, R600a) and brand of oil. An error in dosage or the presence of air in the system will lead to rapid breakdown of the compressor.
Malfunctions of the thermostat and sensors
Electronics controls physics. If thermostat or the electronic control module “thinks” that the chamber is already cold, it will not turn on the compressor. In older models, the mechanical thermostat can be checked by closing the contacts directly. If the refrigerator is working, we change the regulator.
In models with electronics (for example, LG, Whirlpool) air sensors are responsible for the temperature. They may lie due to oxidation of contacts or aging. The error is read in service mode. Often the evaporator temperature sensor fails, giving a false signal that defrosting was successful, although the ice has not yet melted.
The sensors are checked with a multimeter in resistance measurement mode. When the temperature changes (heating in your hand or cooling in the refrigerator), the resistance should change smoothly. If there are no surges or the resistance is zero/infinity, the sensor needs to be replaced.
The influence of the environment and improper operation
The breakdown does not always lie in the details. If the refrigerator is located close to the wall, the air circulation around the condenser is impaired. The unit overheats and goes into protection. The temperature in the room also affects: if the room is hotter than +30°C, the refrigerator may not be able to cope, and if it is colder than +10°C (on the balcony), the oil in the compressor thickens.
The load in the chambers also plays a role. If you put a bucket of hot soup in a warm chamber, the compressor will work hard, trying to reduce the temperature. At some point, it may overheat and turn off via a thermal relay.
- 🌡️ The room temperature is below +10°C or above +35°C.
- 🧱 No gap between the back wall and the furniture (at least 5-7 cm).
- 🍲 Loading hot products.
- 🚪 The door is not tightly closed or the seal is worn out.
Check the rubber seal around the perimeter of the door. If it does not fit tightly, warm, moist air enters. This leads to increased ice formation and system overload. A simple test with a sheet of paper will help identify leaks.
When you need to call a technician
If you checked the socket, defrosted the unit, checked the relay, but the problem did not go away, it’s time to call a professional. Especially when it comes to refilling with freon or replacing the compressor. These jobs require a license, tools and experience. Independent intervention in the freon circuit often leads to the final destruction of the equipment.
The technician will conduct a full diagnosis: check the current consumption, pressure in the system, and the tightness of the circuit. Only after this can you say for sure why the refrigerator does not heat or freeze. Repairs can take from 1 hour to several days if the unit needs to be replaced.
Do not delay repairs. An idling compressor burns a lot of electricity and wears out quickly. Timely replacement of a cheap sensor or relay will save an expensive motor from burning out.
Why does the refrigerator hum, but does not freeze?
Most likely, the problem is a lack of freon circulation (clogging or leakage) or a jammed compressor. The compressor tries to start or works without load, but the cooling capacity is zero.
How long should the refrigerator cool down after defrosting?
Usually, raising the temperature to operating mode takes from 2 to 6 hours, depending on the volume of the chambers and the ambient temperature. You should not load food at this time.
Is it possible to use the refrigerator if it does not heat from the back?
No, this is a sign that the cooling cycle has not started. Products will begin to deteriorate. It is necessary to find the reason: either the motor does not turn on, or there is no freon.
What to do if it is warm in the refrigerator compartment and ice in the freezer?
This is a classic sign of a malfunction of the defrost system or a blockage in the circuit. Ice blocks the cold air passages into the upper chamber. Defrosting and diagnostics of the heating element are required.