Situation, when refrigerator stops cooling, and its engine is silent, it takes every owner by surprise. The absence of a characteristic buzz or, conversely, an attempt to start followed by a click and silence are sure signs that compressor cannot enter operating mode. In modern models, such as Indesit, Atlant or Bosch, the reasons may be hidden either in a simple network overload or in a complex electronic breakdown.
Before calling a technician or looking for a new one unit, it is worth conducting initial diagnostics. Often the problem is solved by replacing an inexpensive start relay or defrosting the system. However, ignoring the symptoms can lead to complete failure of an expensive motor. If the compressor heats up to a red-hot state, but does not start, further independent attempts to turn on are prohibited in order to avoid a fire.
Primary diagnostics and checking the power supply
The most commonplace, but often ignored reason — no voltage in the outlet or damage to the cord. Visually inspect the power cable for kinks, signs of rodents, or melted insulation. If the outer part is intact, check the presence of current in the socket itself by connecting another device to it, for example, a lamp or hair dryer.
In some cases, the problem lies in poor contact of the plug with the socket of the socket. Weak contact causes sparking and a voltage drop, which starter is not enough to start. Try plugging the refrigerator into a different outlet, preferably one with grounding, to eliminate problems with the wiring in the apartment.
If you use an extension cord or surge protector, make sure that their rated power matches the needs of the refrigeration unit. A weak filter can act as a fuse during peak loads when starting the engine. It is also worth checking the integrity of the internal wire running from the plug to the terminal block inside the case.
It is important to consider that modern inverter models are sensitive to voltage surges. If your network experiences frequent fluctuations, the compressor may be blocked by the protection system. In this case, a stabilizer or a pause of 20-30 minutes before turning it on again will help.
☑️ Initial electrical check
Faults in the start protection relay and thermostat
The most common cause of startup failure is the failure of the start relay. This small unit is responsible for supplying an impulse to the starting winding of the motor. If the relay is “stuck” in the open or closed state, the motor will either not receive a starting impulse, or will hum but not rotate.
Thermostat (or temperature sensor in models with No Frost) is another candidate for checking. If it does not close the circuit when the temperature in the chamber rises, the signal to start the compressor simply will not be received. In older models with mechanical control, the contacts inside the regulator itself often oxidize.
To diagnose the relay, you need to remove the back cover at the bottom of the refrigerator. Carefully remove the plastic casing from the side of the compressor. Inside you will see a black box - this is the relay you are looking for. You can check it with a multimeter for a break or “ring” the contacts.
⚠️ Attention: Before removing any parts, be sure to unplug the refrigerator! Even after switching off, a residual charge may remain in the capacitors, which can cause an electric shock.
Often inside the relay you can hear the rattling of a ball, if it is a device with a posistor, or see traces of carbon deposits on the contacts. Replacing this part is usually inexpensive and does not require special skills, except the ability to work with a screwdriver.
How to check the relay without instruments?
Gently shake the relay near your ear. If a ringing or knocking sound of the ball is heard inside, it means that the posistor or mechanical part is damaged - the part requires replacement. In good condition, it should be quiet inside.
Problems with the capacitor and motor windings
The starting capacitor helps create the necessary phase shift to start the rotor. If it is swollen, has lost capacity or is punctured, the compressor will try to start, hum, but then stop. You can check it visually (blowing of the housing) or with a special device.
A more serious problem is an interturn short circuit in the motor windings. This can happen due to overheating, aging insulation, or a power surge. In this case, the resistance of the windings will differ from the nominal one, and the motor will consume increased current, causing the protection to trip.
To diagnose the windings, use a multimeter in resistance measurement mode. The normal resistance of the working winding is usually 10-30 Ohms, the starting winding is 20-50 Ohms (values depend on the model). If the device shows one (open) or zero (short circuit), the engine is faulty.
| Symptom | Probable cause | Solution |
|---|---|---|
| Silence, no reaction | Open circuits, thermostat, relay | Replacing the relay or thermostat |
| Humming and clicking | Stuck, relay, capacitor | Checking the capacitor and relay |
| The motor is heating up, not turns | Interturn short circuit | Replacing the compressor |
If a short circuit to the housing is detected (one of the winding wires is connected to a copper tube), it is dangerous to operate such a compressor. It requires professional rewinding or, which is most often more economically feasible, complete replacement.
Mechanical compressor wedge
Sometimes the electrical part is working, but the engine rotor cannot budge due to mechanical jamming. This occurs when friction pairs wear out, metal shavings enter the system, or during prolonged downtime of equipment. In this case, the motor emits a dull hum and quickly heats up.
There is a “wedging” method by increasing the voltage, but it requires special equipment and is dangerous for inexperienced users. The essence of the method is to briefly apply increased voltage to the starting winding in order to rip the rotor out of place.
A safer, but more labor-intensive method is to dismantle the compressor, warm it up and try to rotate the shaft manually (after removing the refrigerant). However, at home it is almost impossible to do this efficiently without losing the tightness of the system.
⚠️ Attention: Attempts to start a jammed compressor directly, bypassing the protection, can lead to a fire in the wiring or an explosion of the refrigerant cylinder due to a sharp increase in pressure.
If you have diagnosed a jam, the most reasonable solution would be to call a technician to replace it unit. Modern compressors are often supplied sealed, and their repair is not structurally provided for.
Faults in refrigerators with an inverter compressor
Equipment owners LG, Samsung or Hitachi with a system Linear Inverter face other problems. There is no classic starting relay, and starting and speed control are carried out by an electronic module. If the inverter does not see feedback from the motor, it blocks the start.
A common reason is the failure of the inverter module itself, located at the bottom of the refrigerator or in the upper part of the case. Power surges often damage sensitive control electronics. Visually, swollen capacitors or traces of burning may be visible on the board.
Diagnostics of inverter systems requires special equipment to check the waveform and voltage on the windings. It is impossible to check the dynamics of the inverter with a conventional multimeter. The error is often displayed on the refrigerator display in the form of a code.
The cost of repairing such systems is much higher due to the price of components. The control module and the linear compressor itself are expensive components, the replacement of which requires qualifications.
Information about error codes and inverter board compatibility may vary depending on the model revision. We recommend checking the fault codes in the manufacturer's official manual or through the service menu of your specific model.
If the refrigerator with an inverter does not start, first try a full reset (unplug it for 15-20 minutes). This will allow you to reload the logic of the controller, which could have gone into error.
When you need to call a professional technician
Independent repair is justified in cases of replacing the thermostat, starting relay or checking the wiring. However, there are a number of situations where the intervention of an amateur can only aggravate the situation and lead to additional costs.
If diagnostics require opening a sealed system (cutting tubes), releasing freon or vacuuming, you cannot do without special equipment and skills. Working with refrigerants requires a license and compliance with safety regulations.
It is also worth contacting specialists if, after replacing the relay, the problem does not disappear, and the new compressor burns out within a short time. This may indicate a blockage in the capillary tube or the presence of moisture in the system, which requires professional purging.
Do not forget that independent intervention in the design often voids the warranty. If the equipment is under warranty, carry out any repairs only through an authorized service center.
Why does the compressor turn on for a few seconds and then turn off?
This is a classic sign of a thermal protection relay tripping. The motor tries to start, the current increases 5-7 times, the winding heats up, and the protection opens the circuit. Reasons: jamming, malfunction of the starting relay, low voltage in the network or interturn short circuit.
Is it possible to start the compressor directly without a relay?
Technically, you can apply voltage directly to the working and starting windings, but this must be done extremely carefully and briefly only for diagnostics. Constant operation without a relay will lead to burnout of the starting winding in a matter of minutes.
How much does it cost to replace a compressor in a refrigerator?
The cost consists of the price of a new unit, the cost of soldering, vacuuming and refilling with freon. Depending on the model and region, the price can vary from 50% to 80% of the cost of a new refrigerator.
Does a working compressor hum?
Yes, a working motor makes a smooth, monotonous hum. Strong vibration, clanging, knocking or intermittent noise indicate faulty bearings, valves or loose mounting bolts.