The situation when the refrigerator has stopped freezingand from its depths the usual hum is not heard, always takes you by surprise. The interior heats up quickly, food begins to spoil, and urgent intervention is required. Most often, the problem lies in the electrical circuit, which is responsible for starting the compressor the heart of the entire cooling system.
Before calling a technician or looking for a replacement unit, it is necessary to carry out a primary diagnostics. Failure of the motor can be caused by either a banal power surge or a serious breakdown of internal components. Understanding the principle of operation trigger mechanism will help you save time and money on repairs.
In this article we will analyze in detail why the engine does not startwhat sounds should alert you and how to safely check the serviceability key nodes. You will learn in which cases self-repair is possible, and when you cannot do without professional intervention.
Diagnostics of failure to start: first steps
The first thing to do if the refrigerator is silentis to listen. The absence of any sounds may indicate an open circuit, a blown fuse, or a malfunctioning thermostat. If you hear a quiet click, followed by an attempt to start, but the motor immediately stalls, the problem is most likely in start relay or the motor windings.
The check begins with a visual inspection and simple measurements. Make sure that the plug is firmly inserted into the socket and that the socket itself is working properly - this can be checked by connecting any other electrical appliance to it. It is also worth inspecting power cord for damage, especially if you have pets or repair work is being carried out in the house.
⚠️ Attention: Before any manipulations with the internal components of the refrigerator, be sure to disconnect the device from the power supply! Working with electricity requires compliance with safety precautions.
If an external examination does not produce results, it is necessary to proceed to a more in-depth diagnosis. Often the reason for this is a malfunction of the thermostat. He may simply “not see” that the chamber has become warm and not give a signal to start the motor. Try to forcefully close the thermostat contacts (after examining the diagram for your model) to check whether the unit will start. the compressor does not turn on, is a malfunction of the thermostat. He may simply “not see” that the chamber has become warm and not give a signal to start the motor. Try forcibly closing the thermostat contacts (after studying the diagram for your model) to check whether the unit will start.
It is important to pay attention to the nature of the sounds that the refrigerator makes when trying to start. Humming without starting, repeated clicks or complete silence - all this diagnostic signsindicating different parts of the breakdown. Accurate identification of the sound will help narrow down the troubleshooting.
Failure of the starting relay and the starting protective device
One of the most common reasons why the refrigerator motor hums, but does not startis the failure of the starting relay. This small component is responsible for supplying an impulse to the starting winding of the engine at the moment of start. If the relay is “stuck” or burned out, the engine cannot go into operating mode and only hums, trying to turn over.
Modern models often use start-up protective device (ROM), which combines the functions of a starter and a thermal relay. It protects the motor from overheating and overcurrent. If the ROM malfunctions, the circuit opens and the compressor remains de-energized, even if the thermostat requires cooling.
To check the relay, it must be removed from the compressor contacts. Visually inspect the case for melting, blackening or cracks. If a ringing sound is heard inside when shaken (for some types of relays) or traces of burning are visible, the part requires replacement. You can also “ring” the contacts with a multimeter in ohmmeter mode.
How to test a relay with a multimeter?
To check, connect the multimeter probes to the relay contacts. In the initial position, the resistance should be zero (closed circuit). If the meter shows infinity or very high resistance, the relay is faulty and needs to be replaced. Important: before checking, make sure that the device is unplugged and cooled down.
Replacing the start relay is one of the most accessible procedures in refrigerator repair. However, it is important to choose an analogue that fully matches the characteristics of your compressor. The power, type of connection and overall dimensions must match, otherwise the new component will also quickly fail or damage the motor.
Problems with the windings of the compressor electric motor
If the starting device is working properly, and the compressor is hummingbut the shaft does not rotate, there is a high probability of problems with the motor windings. The electric motor of the refrigerator has a starting and operating winding. An insulation failure, an interturn short circuit or a wire break leads to the fact that the magnetic field is not formed correctly and the rotor cannot start rotating.
Diagnostics of the windings is carried out using a multimeter. It is necessary to measure the resistance between the contacts on the compressor housing. Normal resistance values are usually in the range of 10 to 30 ohms for the operating winding and slightly higher for the starting winding. If the device shows zero (short circuit) or infinity (break), the engine is faulty.
The situation when this happens is particularly dangerous. breakdown to the housing. In this case, the current begins to flow to the metal part of the unit, which not only blocks the start, but also creates a threat of electric shock. You can check this by measuring the resistance between any contact and the copper tube or compressor housing - it should be infinite.
| Type of fault | Multimeter readings | Repairability | Recommendation |
|---|---|---|---|
| Winding break | Infinity (∞) | Rewind required | Replacement of the compressor |
| Interturn short circuit | Resistance below normal | Complicated repair | Replacement of the compressor |
| Breakage to the housing | Resistance 0 or low | Impossible | Urgent replacement |
| Normal | 10-30 Ohm (working) | Good | Looking for the cause in the relay |
Unfortunately, rewinding the compressor in everyday conditions it is practically impossible and economically impractical. The sealed housing is difficult to disassemble and reassemble without losing its properties. Therefore, if a defect in the windings is confirmed, the only correct solution is replacing the compressor to a new one.
Jagging of the mechanical part of the compressor
Sometimes the electrical part of the motor is fully operational, current is consumed, a magnetic field is created, but the motor does not start due to mechanical jamming. This happens when the rubbing parts inside the compressor (pistons, shafts) stick to each other due to lack of lubrication, moisture or prolonged downtime of the equipment.
In such cases, the engine emits a characteristic hum, trying to overcome the resistance, but cannot budge. If you leave the refrigerator in this condition, the windings will quickly overheat, and the thermal protection will trip or the motor will completely burn out. Therefore, if a hum appears without starting the refrigerator must be turned off immediately.
There is a “wedging” method, which sometimes helps to revive the unit. It consists of applying increased voltage to the starting winding for a short time to create a powerful jerk. However, this method is risky and requires special equipment and skills. At home, it is safer to try to gently tap the compressor housing with a rubber mallet to shake off the jammed parts.
⚠️ Attention: The wedging method should only be used by professionals. Inept handling of high voltage can lead to final breakdown of the compressor or fire.
If mechanical jamming occurs due to the exhaustion of its resource, then any starting measures will be temporary. Compressor is a mechanism with a limited service life, and its jamming often indicates that the resource has been exhausted. In this case, replacing the unit is the only long-term solution.
The influence of the thermostat and the starting capacitor
Do not forget that the commander in the cooling orchestra is thermostat. It is he who closes the circuit when the temperature in the chamber rises above the set value. If the thermostat contacts have oxidized or the mechanism is stuck in the “open” position, the signal to start the motor simply will not be received, and the refrigerator will be silent, despite the warmth inside.
You can check the thermostat by temporarily removing it from the circuit. To do this, the wires coming from the thermostat are connected directly (shorted). If after this procedure the refrigerator started, then the problem is in the temperature sensor, and it needs to be replaced. This is an inexpensive and quick procedure.
In some models of refrigerators, especially those equipped with asynchronous motors, starting capacitorplays an important role. It creates the phase shift necessary to create torque at start. If the capacitor is dry or swollen, the engine will not be able to gain the required speed and start. Checking the capacitor is also carried out with a multimeter with a capacity measurement function.
- 🔍 Inspect the capacitor for swelling of the housing or electrolyte drips.
- ⚡ Measure the capacitance of the device: it should correspond to the marking with a tolerance of ±5-10%.
- 🔄 When replacing, use a capacitor with similar voltage and capacitance parameters.
Often users confuse the symptoms of a malfunction of the thermostat and the start relay. If the refrigerator does not turn on at all and does not click, it is most likely a problem with thermostat or the wiring. If it clicks and buzzes, the relay or compressor is to blame. Correct diagnostics begins with an analysis of the behavior of the device.
When you need to call a professional technician
Despite the possibility of self-diagnosis, there are situations when qualified intervention is indispensable. If you checked the socket, thermostat and relay, but the engine does not startthe problem may lie deep in the system. For example, a refrigerant leak or a clogged capillary tube, which can also block engine operation through the protection system.
Replacing a compressor is a complex technological process that requires special equipment: a vacuum pump, a pressure gauge station, a burner and a supply of freon. An independent attempt to replace without knowledge of soldering technology and the rules for vacuuming the system will lead to the fact that the new compressor will burn out in a few days or weeks.
☑️ When to call a technician
In addition, modern refrigerators are equipped with complex control electronics. If you have a model with a system No Frost and an electronic module, the reason may be a failure of the control board, which does not supply voltage to the compressor. Diagnostics of such systems requires special knowledge and circuits.
Do not ignore signs of malfunction. Timely repairs allow you to save products and avoid more expensive replacement of entire units. If you doubt your abilities, it is better to entrust the equipment to professionals who guarantee the quality and safety of the work performed.
Is it possible to repair a burnt-out compressor?
In a domestic environment, repairing a burnt-out compressor is impossible. The sealed housing is not intended for disassembly, and rewinding the windings requires industrial equipment. The only way out is to replace it with a new unit.
Why does the refrigerator click but does not turn on?
Clicks are usually produced by a starting relay or thermal protection relay. This means that current is supplied to the motor, it is trying to start, but something is interfering (jamming, malfunction of the windings or the relay itself). Cyclic clicks are a sign that the protection is working.
How long can a refrigerator operate with a non-working motor?
Without a working compressor, the refrigerator retains cold from 4 to 24 hours, depending on the model, load and ambient temperature. Do not open the doors to extend this period until the technician arrives.
Is it dangerous to change the starting relay yourself?
If you follow safety precautions (disconnect the device from the network) and have basic skills in working with tools, replacing the relay is safe. The main thing is to choose the right analogue and install it in the correct position.