The situation when the refrigerator does not startand it’s already starting to get warm inside causes panic in any home cook. Silence in the kitchen instead of the usual hum is the first warning sign indicating a malfunction of the cooling system. Most often, the problem lies in compressor the heart of the unit, which is responsible for the circulation of the refrigerant. However, before calling a technician or preparing for complex repairs, it is worth carrying out an initial diagnosis, since the reasons may be trivial.
In this article we will analyze a step-by-step algorithm of actions that will help you understand why engine does not respond to turn on. We will look at both simple faults that can be fixed with your own hands, and complex technical breakdowns that require the intervention of a professional. It is important to act consistently and follow safety precautions when working with electricity.
The first thing to do is to eliminate external factors. Check to see if there is power at the outlet, if the power cord is working, and if the doors are closed tightly. Sometimes thermostat it simply does not receive a signal about an increase in temperature if the door is skewed. If everything is in order with the electricity, but the motor is still silent, you will have to move on to a more detailed diagnosis of the internal components.
Primary diagnostics and checking the electrical circuit
You should always start troubleshooting by checking the voltage supply. Even if the light is on in the room, there may be a bad contact in a particular outlet or a blown fuse in the panel. Use a multimeter or plug another working electrical device into the outlet to make sure there is current. Lack of power is the most common reason why compressor does not start.
Next, carefully inspect the power cord and plug. There should be no traces of melting, cracks or kinks on them. If you find damage to the insulation, operate such a refrigerator strictly prohibited to avoid a short circuit. It is also worth checking the integrity of the wire inside the camera if the model allows visual inspection without disassembly.
An important element of the circuit is thermostat. In older models it is mechanical, in new ones it is electronic. If the thermostat is faulty, it breaks the power supply to the engine, and it does not receive a command to start. Try to forcefully close the thermostat contacts (after disconnecting the refrigerator from the network!). If after this the motor starts humming, then the problem is in the temperature sensor.
⚠️ Attention! Carry out all manipulations with electrical circuits only with the device completely disconnected from the network. Do not touch exposed live wires, this is deadly.
To systematize checking the main elements of the power circuit, use the following table:
| Check element | Fault symptom | Diagnostic method |
|---|---|---|
| Socket and network | Indicators do not light up, the motor is silent | Tester or connecting another device |
| Power cord | Visual damage, sparking | Visual inspection, continuity |
| Thermostat | The refrigerator does not turn on at all | Closing of contacts bypassing the sensor |
| Internal wiring | Open circuit, traces of burning | Visual inspection, multimeter |
Diagnostics of the starting relay and fusible capacitor
If the network is working, but the refrigerator does not start, most often the starting relay is to blame. This is a small device that provides an impulse to start the motor winding. Modern models often use a posistor, while older models often use an electromagnetic relay with a coil. It is this unit that fails in 40% of cases when the compressor is silent.
To check the relay, it must be removed from the compressor. It is usually secured with latches or screws and fits over the three motor pins. Carefully disconnect the wires and remove the device. Shake it near your ear: if a ringing or knocking sound is heard inside, it means the contacts are burnt or the mechanism is destroyed. In this case, it is necessary replacement of the relay.
Together with the relay, the fusible capacitor (if there is one in the circuit) is often checked. It serves to smooth out inrush currents. Bloating of the housing or leaks of electrolyte indicate a malfunction. You can also check the capacitor with a multimeter in capacitance measurement mode, although visual defects are less visible.
How to choose the right relay analogue?
When buying a new starting relay, pay attention not only to the model of the refrigerator, but also to the power of the compressor. There is always a marking on the relay body, for example, RTK or R-3. If you buy a relay with the wrong power range, the compressor will either not start or will be overloaded, which will quickly cause it to burn out. It is better to take the old relay with you to the store for comparison.
The process of replacing the relay is simple: remove the old one, take a photo of the wiring diagram and install the new one in the same sequence. Make sure the contacts are firmly seated on the compressor terminals. After assembly, plug in the refrigerator. If a click is heard and the engine starts, the problem is solved.
Why it hums, but does not start: sound analysis
The situation when the compressor is hummingbut does not start is different from complete silence. Humming means that current is flowing to the windings, but the rotor cannot move. This may be caused by jamming of the mechanism, breakdown of the windings, or insufficient starting torque. The nature of the sound helps determine the type of malfunction.
If you hear a steady hum, which after 5-10 seconds is replaced by a relay click and quieting down, and then the cycle repeats, this indicates a thermal breakdown. The engine tries to start, consumes a lot of current, heats up, and the thermal relay opens the circuit. This is a classic symptom interturn short circuit or mechanical jamming of the piston group.
Sometimes the hum is intermittent, with a metallic clang. This may indicate that the compressor has been torn from the frame and is hitting the refrigerator body when trying to start. In this case, you need to check the mounting bolts and shock absorbers. If the motor hums quietly but confidently, it may not have enough voltage in the network or the starting device is faulty.
☑️ Diagnosis of a humming compressor
It is important not to leave the refrigerator in state of "buzz" for a long time. Each such attempt to start overheats the windings and can finally finish off the engine, which is still working. If after replacing the relay the situation has not changed, serious repairs or replacement of the unit will probably be required.
Checking the motor windings with a multimeter
To accurately diagnose the condition electric motor a multimeter is required. With its help you can check the integrity of the windings and the absence of a short circuit to the housing. This is a critical stage that allows you to understand whether the motor is alive or needs to be changed. Before checking, make sure that the device is disconnected from the mains.
Remove the protective cover at the back of the refrigerator and get to the compressor contacts. There are usually three of them: general, starting and working. Remove the start relay and capacitor to clear the contacts. Switch the multimeter to resistance (ohms) measurement mode. First check the resistance between each pair of contacts. It should be between 10 and 30 ohms. If the device shows infinity, there is a break; if it is zero, there is a short circuit.
Then check the resistance between any contact and the copper tube or compressor housing. Here the multimeter should show infinity (one in the leftmost position). If there is any resistance value, it means that breakdown to the bodyoccurred. Operating such a refrigerator is dangerous; it can cause an electric shock through the metal casing.
⚠️ Attention! If you find a breakdown of the windings on the housing, further independent operation is prohibited. Such a compressor is only subject to disposal or complex professional repairs, which are often not economically feasible.
Measurement results should be recorded in order to compare them with the model data sheet, if available. However, even without a passport, an obvious break or short circuit is immediately visible. If the windings are intact, but the motor does not spin, the problem may be in the mechanical part.
Mechanical compressor wedge and souring
One of the most unpleasant reasons why the refrigerator does not startis a mechanical wedge. Inside the sealed motor housing, rubbing parts (pistons, shafts) could lose lubrication or become covered with wear products. As a result, the rotor cannot turn, despite the supply of voltage.
Sometimes the compressor “sours” after a long period of inactivity. If the refrigerator has not been used for several months, the oil may have thickened or drained into the lower part of the crankcase. In such cases, the “rocking” method sometimes helps, but it requires caution. The essence of the method is to apply voltage directly to the working and starting windings, bypassing the relay, in order to create maximum torque.
For this, a special circuit with a button and a capacitor is used. Voltage is applied to the contacts for 3-4 seconds. If there is a powerful jerk and the hum is replaced by work, you are lucky. If there is a dull thud and silence, or smoke starts to appear, the compressor is jammed tightly. Attempts to wedge it with a hammer or by heating at home rarely give long-lasting results.
It is worth noting that modern inverter compressors Linear Inverter or Digital Inverter are designed differently. They do not have a classic start relay, and the start is controlled by an electronic unit. If such a motor does not start, diagnostics with a multimeter often show serviceable windings, but the reason lies in the control board or rotor position sensors.
Replacing a compressor: is it worth the candle?
If diagnostics showed that the compressor burned out or jammed, the question arises: replacing it. This is a complex procedure that requires special equipment: a burner, a vacuum pump, a pressure gauge station and freon supplies. You cannot simply “resolder” the tubes and screw in a new motor - the system must be evacuated and filled with refrigerant strictly by weight.
The cost of a new compressor for a household refrigerator is a significant part of the price of a new device. work of a technician, refilling with freon and leaving, the total amount can reach 50-70% of the cost of a new refrigerator. Therefore, it is economically justified to change the compressor only on expensive models or if you plan to do it yourself, having the skills and tools.
The replacement process includes:
- 🔥 Cutting off old filling tubes and removing the faulty motor.
- 🔧 Installing a new compressor and soldering connections in a nitrogen environment (so that there are no oxides inside).
- 💨 Evacuating the system for 30-40 minutes to remove moisture and air.
- ❄️ Filling the system with freon through a capillary tube or service valve.
- 🧪 Checking the system for tightness and performance.
If you do not have the skills to solder copper pipes and work with refrigerants, it is better not to take on this work. Improper soldering will lead to freon leakage in a month, and the presence of moisture in the system will lead to the formation of an ice plug and failure of the new compressor.
Frequently asked questions and answers (FAQ)
Can a refrigerator not start due to a defrost sensor?
Yes, in No Frost systems, a faulty defrost sensor or heating element can block the start of the compressor. The electronics sees an error in the defrost system and goes into protective mode without turning on the motor to avoid freezing of the evaporator.
How long does a refrigerator compressor last on average?
The average service life of a high-quality compressor is 10-15 years. However, with frequent voltage fluctuations, overheating or mechanical damage during transportation, it may fail much earlier. Inverter models claim a service life of up to 20 years.
Why does the refrigerator not turn on after defrosting?
If after defrosting The refrigerator does not startmoisture may have gotten into the electrical contacts of the thermostat or relay. Allow the device to dry completely for 24 hours. The protection could also work if you turned it on immediately after defrosting - wait 2-3 hours.
Is it dangerous to use a refrigerator with a humming compressor?
Yes, it is dangerous. Constant attempts to start overheat the windings, which can lead to insulation fire or wiring melting. In addition, this creates unnecessary load on the power grid. It is better to turn off the device until the reasons are found out.