The situation when refrigerator stops turning off the compressor and works continuously, familiar to many equipment owners. This phenomenon is alarming because it leads to a sharp increase in energy bills and can signal serious problems with the cooling system. Unlike older models, modern units with the system No Frost have a more complex electronic control circuit, where sensors and thermostats are responsible for stopping the engine.
To understand why compressor buzzes without interruption is possible only by consistently eliminating faults. Often the problem lies not in the motor itself, but in a violation of heat exchange or malfunction of the control elements. Ignoring this symptom can lead to overheating of the engine and the need for an expensive replacement of the entire unit.
In this article we will analyze the main reasons why your refrigerator does not turn offand determine which of them can be eliminated yourself, and when it is better to call a technician. It is important to listen carefully to the operation of the equipment and monitor the temperature inside the chambers.
⚠️ Attention: If you smell burning or see sparking in the compressor area, immediately disconnect the device from the network to avoid a fire.
Malfunctions of the thermostat and sensors temperature
One of the most common reasons for the continuous operation of a refrigerator is failure thermostat. This element is responsible for breaking the electrical circuit when the temperature in the chamber reaches the specified values. If the contacts inside the thermostat “stick” in the closed position, the compressor will receive current constantly, even if the food is already frozen.
In models with electronic control, the thermostat function is performed temperature sensors (thermistors). They are resistors whose resistance changes depending on heat. If a sensor breaks down, it can transmit incorrect data to the control module that there is “heat” in the chamber, causing the system to cool the air endlessly.
Diagnostics of these elements requires the use of a multimeter to measure resistance. In mechanical thermostats, the bellows tube, which must respond to changes in refrigerant pressure, often breaks. In electronic systems, sensors simply burn out or their contacts oxidize.
- 🔍 Check whether the capillary tube of the mechanical thermostat has moved from the chamber wall.
- ❄️ Test the thermistor with a multimeter: as the temperature changes, its resistance should change.
- 🔧 Make sure that the wires going to the sensors are not broken and have reliable contact with the board.
⚠️ Attention: Replacing the thermostat in electronically controlled refrigerators often requires flashing or adjusting the module, which only specialists can do.
Refrigerant leaks and problems with tightness
When freon leakoccurs in the circulation circuit, the pressure in the system drops. Sensors detect that the required temperature has not been reached and command the compressor to work longer and more intensely. However, due to a lack of refrigerant, the cooling efficiency drops, and the refrigerator enters an endless operation mode, trying to compensate for the losses.
In systems No Frost leaks often occur at the soldering points of the evaporator or in the foamed parts of the housing. It is impossible to visually notice a gas leak, since freon is colorless and odorless. An indirect sign may be a weak cold pressure or the formation of ice in only one corner of the freezer.
If you notice that the condenser (grid at the back) remains only partially cold or warm, this is a sure sign of a leak in the circuit. In such a situation, the compressor works for wear, trying to create the required pressure, which physically cannot be achieved.
Clogged capillary tube or filter-drier
Another technical reason why refrigerator does not turn off is clogged capillary tube or filter-drier. In the refrigerant circulation system, oil oxidation products, moisture or small debris can accumulate, which blocks the flow of liquid.
When clogged, the compressor tries to push freon through the plug, creating excess pressure in front of the blockage and a vacuum after it. This leads to the fact that the evaporator does not cool evenly, the sensors do not detect the cold, and the motor continues to hum. Often, you can hear a characteristic gurgling or whistling sound.
To eliminate this problem, you need professional blowing the system nitrogen and replacement of the filter-drier. It is difficult to perform this operation on your own, since it requires evacuation of the system and precise charging of refrigerant by weight.
Pressure in the system: 0.06 - 0.08 MPa (for R600a)
Pressure in the system: 0.4 - 0.6 MPa (for R134a)
Violation of the thermal insulation and tightness of the chambers
If sealing rubber the door is worn out, dirty or deformed, warm air from the room constantly penetrates into the chamber. The refrigerator tries to cool this incoming volume, and the compressor does not receive a signal to stop. This is the most common reason, which is easy to check visually.
Thermal insulation may also be damaged due to mechanical damage to the housing or manufacturing defects. If heat penetrates the walls, the temperature sensor will constantly record an excess of the norm. In models No Frost the problem may lie in a loose fit of the air duct damper between the chambers.
Checking the tightness can be done using a sheet of paper. Clamp the sheet with the door around the perimeter: if it falls out or is pulled out without resistance, then the seal is broken. Regular cleaning and lubrication of rubber bands helps extend their service life.
☑️ Checking the door tightness
Incorrect operation of the defrost sensor
In system refrigerators No Frost the correct cycle is critical defrosting. If defrost sensor (defroster) is faulty, it may not inform the controller that the evaporator is covered with ice, or, conversely, block the compressor from starting. However, a more common scenario is when the system “freezes” in cooling mode.
If the defrost heating element or timer (if it is mechanical) malfunctions, ice freezes on the evaporator in a thick layer. This ice blocks the air circulation channels. The fan moves the air, but there is no cold. The temperature sensor in the chamber “screams” about heat, and the compressor works non-stop, trying to break through the ice plug.
Visually this is manifested by the fact that barely warm air is blowing from the vent in the freezer or not blowing at all, although the motor is running. Complete defrosting of the refrigerator within 24 hours is required to test this hypothesis.
| Symptom | Probable cause | Action |
|---|---|---|
| Ice on the back wall | Malfunction Defrost heating element | Replacing the heater |
| Fan noise | Ice on the blades | Defrost 24 hours |
| Compressor hot | Overload due to ice | Checking sensors |
| Frost on products | Defrosting cycle failure | Timer diagnostics |
⚠️ Attention: If after complete defrosting (24 hours without connecting to the network) the refrigerator started working normally, but a week later the problem recurred, one of the elements of the defrosting system is faulty.
Problems with the electronic control module
Modern refrigerators are controlled electronic module, which receives signals from all sensors and decides whether to turn the compressor on or off. If relays burn out on the control board, tracks oxidize, or the microcontroller fails, commands may be issued incorrectly.
Often the module “sticks” in cooling mode due to power surges in the network. In this case, even working temperature sensors cannot stop the engine, since the “brain” of the refrigerator ignores their signals. Repairing the module requires soldering skills and knowledge of electronics.
Sometimes it helps by simply resetting errors disconnecting the device from the network for 15-20 minutes. If, after turning on, the refrigerator begins to operate normally, it means that a software failure has occurred. If the situation repeats, the board or its components need to be replaced.
Is it possible to repair the module yourself?
Independent repair of the board is possible only if you have experience working with electronics and a soldering iron. It is necessary to ring the tracks, check the capacitors for swelling and replace burnt out relays. However, without a circuit and an oscilloscope, there is a high risk of permanently damaging the board.
The influence of external factors and improper operation
Do not forget about external factors. If the refrigerator is installed too close to a wall, a radiator, or in direct sunlight, the heat transfer from the condenser is impaired. The compressor overheats and cannot effectively cool the refrigerant, running idle.
Loading the refrigerator with warm food also forces it to work in increased mode for a long time. In addition, frequent opening of doors in a hot room creates a constant influx of warm, humid air, which the system No Frost cannot cope with.
Check the gap between the back wall of the refrigerator and the wall of the room. It should be at least 5-7 cm for free air circulation. Also make sure that the room is not too hot: most models are not designed to operate at temperatures above +32°C.
Frequently asked questions (FAQ)
How long should it work Is the compressor normal?
In normal mode, the compressor operates cyclically: it works for about 10-15 minutes and rests for 20-30 minutes. The work rate is approximately 30-40% of the total time. If the refrigerator operates continuously for more than 1 hour without a break in an empty chamber, this is a malfunction.
Is it dangerous if the refrigerator does not turn off for a day?
Yes, it is dangerous. Long-term operation without breaks leads to overheating of the motor windings, oil burnout and eventual jamming of the compressor. The risk of a wiring fire also increases significantly.
Could the "Super Freeze" mode be the cause?
Yes, if you accidentally activated the function Super Freeze or Quick Cool, the refrigerator will work without stopping until you turn off this mode manually or the programmed time has passed (usually 24-48 hours).
Why does a new refrigerator work constantly?
When turned on for the first time, a new refrigerator takes up to 24 hours to gain temperature and stabilize the mode. During this period, continuous operation of the compressor is the norm.