The situation when No Frost refrigerator stops turning off and works around the clock is familiar to many owners of modern equipment. In normal mode, the compressor should turn on and off cyclically, maintaining the set temperature inside the chambers. If the motor hums continuously, this indicates that the control system detects an inability to achieve target indicators or has received a false signal about the need for cooling.
Ignoring this problem can lead to serious consequences: from food spoilage due to freezing to failure of an expensive one compressor due to overheating. Continuous operation of the motor for 24 hours often indicates depressurization of the circuit, which requires immediate intervention by a technician. In this article we will analyze in detail the mechanical and electronic causes of the malfunction, as well as methods for eliminating them.
Violation tightness of the chambers and wear of the seal
The most common, but common reason is a violation of the thermal insulation of the internal volume. If warm air from the outside constantly enters the chamber, thermostat or the electronic control module will require the compressor to operate continuously to compensate for heat inflows. In systems No Frost this is especially critical, since the moisture contained in the incoming air actively freezes on the evaporator.
First of all, you need to carefully inspect sealing rubber (cuff) around the perimeter of the door. Over time, the rubber profile loses elasticity, cracks or deforms. Even a microscopic gap of 1-2 millimeters creates a constant flow of warm air, which the cooling system simply does not have time to “overcome.”
It is also worth checking the geometry of the door itself. If the refrigerator was overloaded with heavy food or was not transported correctly, the door could become warped. In this case, a tight fit becomes physically impossible, and refrigerator compartment cannot maintain the temperature.
⚠️ Attention: Do not try to forcefully slam the skewed door or glue the seal with superglue. This will lead to destruction of the rubber structure and will require replacing the entire cuff.
For quick diagnosis, you can use a simple method with a sheet of paper. Clamp the sheet between the door and the body at various points around the perimeter. If the paper comes out too easily or falls out on its own, the seal is broken. In such cases defrost mode it may turn on more often than usual, trying to remove excess ice, but the compressor will wear out.
Problems with temperature sensors and thermostat
The refrigerator electronics rely on sensor readings. If thermostat (in mechanical models) or temperature sensor (in electronic) fails, it can transmit false data to the control module that it is too warm inside the chamber. Receiving such a signal, the controller does not give a command to stop the engine.
In models with the system No Frost several sensors are often used: one monitors the air temperature in the chamber, the other controls the degree of freezing of the evaporator. Failure of any of them leads to incorrect operation of the algorithms. For example, if the evaporator sensor is “shorted” in the “cold” position, the system may not start defrosting, which will lead to fouling and, as a result, to continuous operation of the compressor to pump air.
Main signs of sensor malfunction:
- 🌡️ The compressor works without interruption, but the temperature in the chamber is lower standards (products freeze).
- ❄️ An ice crust forms on the back wall of the chamber, although the system No Frost should prevent this.
- 🔌 When the thermostat is mechanically turned off (turning the knob to minimum), the motor does not stop.
Replacing the thermostat is a relatively simple procedure, but requires precise adjustment. Electronic sensors require checking with a multimeter to ensure that the temperature resistance is appropriate. If you do not have the skills to work with electrical appliances, it is better to entrust this operation to a specialist.
☑️ Symptoms of sensor malfunction
Refrigerant leakage and capillary system blockage
One of the most serious technical problems is a violation of the tightness of the refrigeration circuit. If a microcrack has formed in the system, freon it begins to gradually evaporate. Its quantity becomes insufficient for effective heat removal, and the compressor is forced to work constantly, trying to compensate for the loss of performance.
A similar situation is observed when clogged capillary tube. Oil wear products or moisture entering the system can clog the thin channel through which the refrigerant enters the evaporator. The pressure in the system drops, circulation stops, but the sensors “see” heat and require the motor to work.
| Symptom | Probable cause | Actions |
|---|---|---|
| Compressor is hot, cold is weak | Freon leak | Call a technician to find a leak |
| The motor works, but does not freeze | Clogged capillary | Purge the system and replace the filter |
| Gurgling and noise are heard | Lack of refrigerant | Refill or recharge the circuit |
Repair the leak yourself or clogging is almost impossible. This requires a vacuum pump, a pressure gauge station and a supply of inert gas or freon. Attempts to “just add gas” without eliminating the cause of the leak will only give a temporary effect.
⚠️ Attention: If you notice oily spots under the refrigerator or in the compressor area, this is a sure sign of a leak. Freon carries with it the oil that lubricates the compressor. Further operation of the engine without oil will lead to its wedge.
Malfunctions of the motor-compressor
Wear of the motor itself compressor is the most costly scenario. Over time, the piston group wears out, compression drops, and the engine loses the ability to create the necessary pressure in the system. It starts to idle without turning off, since it cannot dial the necessary parameters.
Also, the problem may lie in the start-up relay. If the relay contacts are stuck in the "on" position, the compressor will receive power constantly, even if the thermostat requires it to stop. This is dangerous due to overheating of the motor windings and the risk of fire.
Signs of problems with the compressor:
- 🔊 Abnormally loud hum, knocking or clanging during operation.
- 🔥 Strong heating of the compressor housing (impossible to touch hand).
- ⚡ Frequent attempts to start followed by a click and stop (thermal protection).
In modern inverter models No Frost diagnosis is even more difficult, since there the control occurs through a frequency converter. A failure in the inverter board can simulate continuous operation, although physically the motor can either accelerate or slow down without stopping completely.
Is it possible to replace the compressor yourself?
Theoretically, it is possible if you have the skills to solder copper pipes, evacuate the system and charge freon by weight. However, without special tools, the quality of the repair will be low, and the risk of damaging the new expensive unit will be high.
Failure of the control module and electronics
The “brain” of the refrigerator is an electronic control module. It is he who processes signals from all sensors and makes decisions about turning on or off compressor and fans. Voltage surges in the network, moisture or manufacturing defects can lead to “sticking” of one of the control transistors or relays.
In this case, the module does not physically open the compressor power circuit. The refrigerator may freeze normally, but not go into standby mode. Often such breakdowns are accompanied by errors on the display (if there is one) or chaotic blinking of indicators.
Diagnostics of electronics requires testing the output circuits of the module. If there is a constant voltage of 220V at the output from the module (or a control signal for the inverter) regardless of the readings of the temperature sensors, the problem is in the board. Repairing the module is possible, but it is often cheaper and more reliable to replace it with a new one, reflashing it or customizing it for a specific model.
⚠️ Attention: Before replacing the module, be sure to check that the wiring is in good condition. Oxidized contacts or frayed wires can give false signals, and replacing the “brains” will not solve the problem.
The influence of external factors and improper operation
The cause is not always a breakdown. Sometimes the refrigerator No Frost does not turn off due to improper operating conditions. For example, if the equipment is installed too close to a wall or in a niche without proper ventilation, heat transfer is disrupted. The compressor overheats and cannot effectively cool the condenser.
It is also worth considering the temperature in the room. If the refrigerator is placed on an unheated balcony or, conversely, next to a hot stove/radiator, it will work at its maximum capacity. The climate class of the device must correspond to the environmental conditions.
Frequent opening of the door, loading a large amount of warm food, or a loosely closed door (due to an interfering package) also force the system to work in enhanced mode. In such cases cooling cycle simply does not complete because the heat gain is too great.
Diagnostics and action algorithm
To understand why your refrigerator does not turn off, you need to act consistently. First, rule out simple household causes, then move on to technical diagnostics. Do not rush to call a technician if the problem is solved by adjusting the door position or defrosting.
Self-testing algorithm:
- Check the tightness of the door and the condition of the seal.
- Make sure that there are no products in the chamber that block the ventilation holes.
- Listen to the operation of the compressor: is there any extraneous knocking?
- Defrost the refrigerator completely (at least 24 hours with the doors open) to eliminate the ice plug in the system No Frost.
- If the problem persists after switching on, professional repairs are required.
If after complete defrosting and checking the tightness, the motor continues to run without interruption, and the temperature in the chamber does not drop to normal - this is a sign of a freon leak or a compressor malfunction. Further operation in this mode will quickly destroy the equipment completely.
Frequently asked questions (FAQ)
Can the refrigerator not turn off in the summer due to the heat?
Yes, in hot weather, heat transfer worsens and the compressor may work longer than usual. However, it still has to stop periodically. If there are no pauses at all, this is a malfunction.
How long should the compressor operate normally?
The work and rest time depends on the model and load, but usually the cycle is: 15-20 minutes of work and 20-30 minutes of rest. The operating coefficient should not exceed 50-60%.
Is it dangerous to leave a refrigerator running non-stop on?
Yes, it is dangerous. The motor may overheat and burn out, and if clogged or leaking, a fire hazard may arise due to overheating of the oil and electrical contacts.
Why does the refrigerator not turn off again after defrosting?
This indicates that the reason is not an ice plug. Most likely, a freon leak has occurred, the compressor has worn out, or the temperature sensors have failed.
Is it possible to repair a refrigerator with a motor that does not turn off with your own hands?
You can replace the seal, thermostat (in simple models) or clean the condenser yourself. Repairing the freon circulation system and replacing the compressor require a license and special equipment.