Situation, when the refrigerator turns on and immediately turns off, is a classic sign of a malfunction in the control system or unit startup. In normal operation, the compressor should operate cyclically: gain temperature and turn off for a long period to maintain cold. If you hear a characteristic click, a hum for a couple of seconds and then silence again, this is a signal that the protective mechanism is blocking the engine from starting.
Ignoring such symptoms can lead to complete failure of an expensive compressor, since each start is accompanied by a high current load. Owners often notice that the temperature in the chamber stops decreasing, food begins to deteriorate, and there is no heat on the rear radiator grille. Diagnostics it is necessary to start with simple actions, excluding external factors, before disassembling the technical unit.
In this guide we will examine in detail the main reasons, why unit behaves this way, and consider the algorithm of actions for independently identifying the problem. It is important to understand that some faults require specialist intervention, but an initial check can be performed without special equipment. Your safety and the safety of the electrical wiring is a priority, so all work is carried out only when the power is turned off.
The main reasons for a short compressor operating cycle
The most common reason that the refrigerator clicks and does not startis a faulty start relay. This small element is responsible for supplying a starting pulse to the motor winding. If the contacts inside the relay are oxidized or burned, the circuit opens and the compressor stalls before it has time to gain speed. Visually, this looks like a series of short starts with an interval of several minutes.
The second most common reason is failure of the Thermostat (thermostat). If the temperature sensor transmits incorrect signals to the control board or directly to the motor, the operating cycle is disrupted. The unit may think that the temperature has already been reached and turn off, or, conversely, try to start, but immediately receive a command to stop due to a voltage surge or error in the thermostat circuit.
- 🔌 Surges voltage: An unstable network causes the protective relay to operate instantly, interrupting the operation of the motor.
- 🌡️ Sensor malfunction: Incorrect temperature readings inside the chamber provoke chaotic switching on.
- 🧊 Evaporator freezing: In No Frost systems, ice can block the fan or defrost sensor.
⚠️ Attention: If you smell burning or see sparking in the compressor area, immediately stop trying to start and unplug the device. Operation in this condition poses a risk of fire.
It is also worth considering the condition of the capacitor, if it is provided for in the design of your model. refrigerator. Swelling or loss of capacity of this element does not allow the engine to develop the necessary torque to start. As a result, the thermal protection is triggered and the cycle is interrupted. Replacing a capacitor is an inexpensive procedure, but requires precise selection of parameters.
Diagnostics of the starting relay and thermal protection
To understand why compressor cannot start, you need to check the starting relay. It is mounted directly on the motor housing and is often hidden by a plastic casing. Remove the back panel of the refrigerator, locate the black cylindrical compressor tank and carefully remove the relay box. Inside you will see contacts and, possibly, a posistor or coil.
Visual inspection often gives the answer: if carbon deposits, melted plastic are visible inside the relay, or the smell of burnt insulation is felt, the part requires replacement. Also try to gently shake the relay near your ear: if you hear a ringing sound, like from broken glass, it means that the posistor has cracked and is not working. This is the most common reason why the refrigerator hums for 5 seconds and turns off.
How to check the relay with a multimeter?
To check, remove the relay and ring the contacts. Resistance should be zero or close to it. If the device shows infinity or one, the circuit is broken. Also check for a short circuit between the contacts and the housing.
Thermal protection, which is often built into the same unit or located nearby, could also burn out. It reacts to overheating of the windings. If it is faulty, it opens the circuit even when the engine is cold. The integrity of the protection circuit is checked with a multimeter in continuity mode.
☑️ Relay diagnostics
When replacing, it is important to select an analogue with exactly the same characteristics Installation. an unsuitable relay can result in the engine either not starting or burning out due to a lack of phase-shifting effect or incorrect holding time of the starting winding.
Problems with the motor starting capacitor
In many modern models, especially with inverter or high-power compressors, starting is carried out using a starting capacitor If the refrigerator turns on for a few seconds and turns off, the reason may be the loss of capacity of this component. The capacitor accumulates energy and releases it at the moment of start, creating the necessary phase shift.
You can visually determine the malfunction by swelling of the housing or leakage of electrolyte, but often the defect is hidden. For accurate diagnosis, a capacitance meter is required. the actual capacity differs from the nominal value by more than 20%, the element must be replaced. Using capacitor with a lower capacity will cause the motor to hum but not start.
- ⚡ Bloating of the housing: A clear sign of breakdown of the dielectric inside.
- 💧 Leakage: Electrolyte out - the capacitor is dead.
- 📉 Loss of capacity: No visible signs, need to be checked with a device.
Replacing a capacitor is easy: it is usually secured with a clamp next to the relay. The main thing is to maintain the polarity if the capacitor is electrolytic (although non-polar ones are more often used in starting circuits). The new element must have the same voltage (or higher) and capacitance.
Compressor malfunctions: wedge and interturn short circuit
The most unpleasant scenario is a malfunction of the very heart of the refrigerator If the compressor is jammed, the piston group cannot move, and the motor tries. turn the shaft, consuming a huge current. The protection instantly reacts and turns off the power. Often this is preceded by a long hum and attempts to start.
An inter-turn short circuit in the motor windings also leads to unit the resistance of the windings. drops, the current increases, and the thermal relay is triggered. You can check the windings with a multimeter by measuring the resistance between the contacts. A short circuit to the housing (insulation breakdown) is also a critical malfunction.
| Symptom | Probable cause | Actions |
|---|---|---|
| Buzzing for 3-5 seconds, clicking, silence | Faulty starting relay | Replacing the relay |
| Motor housing gets very hot | Stuck or shorted | Replacing the compressor |
| Starts, but there is no cold | Freon leak | Searching for leaks, refilling |
| Chaotic switching on | Thermostat is faulty | Replacing the thermostat |
If the diagnostics show that the relay and capacitor are working, but the motor still does not start or knocks out the protection, the compressor will most likely need to be replaced. This is a complex procedure that requires evacuation of the system and charging of refrigerant, which is best left to professionals.
The influence of the thermostat and temperature sensors
Thermoregulator is a device that gives the command to turn the compressor on and off depending on the temperature in the chamber. If the refrigerator often turns on and off., perhaps the thermostat contacts are “stuck” or it has lost calibration. In mechanical models, this is a simple tube with a bellows; in electronic models, it is a resistance sensor.
In models with a system No Frost and electronic control, several sensors are responsible for the temperature. If one of them (for example, the evaporator sensor) shows an error, the control board may block the start of the compressor or turn it on in emergency mode. Often, an error code lights up on the display.
Checking a mechanical thermostat is simple: short-circuit the two wires going to it directly. If the refrigerator runs continuously, the thermostat is faulty. However, you cannot operate the device in this mode for a long time - the food will freeze.
⚠️ Attention: When replacing the thermostat, it is important not to bend the capillary tube. Mechanical damage to the tube will cause freon to leak from the thermostat and it will stop working.
Electronic sensors are checked by measuring resistance at different temperatures. Their characteristics must correspond to the manufacturer's table. A deviation of several kilo-ohms can be perceived by the board as a critical situation.
Problems with power supply and wiring
Sometimes the reason lies not in the refrigerator, but in the external environment. If in your apartment voltage jumps, the protective relay inside the device will constantly operate. Check the voltage at the outlet using a multimeter or voltmeter. The range of 220V ± 10% is considered normal.
Loose contacts in the socket or plug of the power cord cause heating and voltage drop under load. When trying to start, the compressor consumes a lot of current, the voltage drops, and the motor stalls. Inspect the plug for melting and blackening.
- 🔌 Socket: Check the tightness of the contact and the absence of sparking.
- 🔌 Extension cord: Do not connect the refrigerator through thin extension cords or tees.
- ⚡ Network: With constant surges, a voltage stabilizer is needed.
Using low-quality surge protectors can also cause problems. They are not designed for compressor starting currents and can open the circuit, mistaking a normal start for an overload.
Specifics of inverter compressors
Owners of modern models with the inscription Inverter may encounter a different picture. Inverter motors do not turn off completely, but change speed. However, if such a refrigerator tries to start and stalls, the problem often lies in the inverter control board. It is very sensitive to voltage surges and the quality of grounding.
Diagnostics of inverter systems is more complicated and requires a special tester to check the signals going to the compressor. Errors are often indicated by blinking LEDs on the front panel. Self-repair of the board is only possible if you have circuit knowledge.
It is important to note that inverter compressors have a lower starting current, but a more complex operating logic. If the board “sees” the resistance of the windings outside the norm, it blocks the start so as not to burn expensive electronics.
Why is an inverter refrigerator quieter?
The inverter motor operates constantly at low speeds, avoiding sudden starts and stops, which reduces noise and wear of mechanical parts, but makes the system more sensitive to electronics.
Frequently asked questions (FAQ)
Why does the refrigerator turn on for 10 seconds and turn off?
Most likely, the thermal protection is triggered due to a faulty start relay or jammed compressor. The motor tries to start, the current increases, and the protection turns off the power to avoid a fire.
Is it possible to temporarily short-circuit the thermostat?
Yes, this is permissible for diagnostics. But for constant operation - no, since the refrigerator will freeze endlessly, which will lead to food freezing and breakdown.
A click is heard, but the refrigerator does not start, what's the matter?
The click is made by a thermal relay or starting device. This means the chain is broken. The reason may be in the relay itself, in the motor windings, or in the absence of a phase/zero in the socket.
How often should a working refrigerator turn on?
In normal mode, the operating coefficient is about 20-40%. That is, he works for 10-20 minutes, rests for 30-40 minutes. Depends on the load and room temperature.
Is it dangerous to frequently turn the refrigerator on and off?
Yes, frequent starts (less than 5-10 minutes after stopping) are harmful to the compressor, since the pressure in the system does not have time to equalize and the oil does not return to the crankcase.