Silence in the kitchen instead of the usual hum is the first alarm signal for any owner of household appliances. When the refrigerator stops freezing, and the engine does not emit a characteristic hum, this can mean either a banal power surge or a serious breakdown of internal components. In most cases, the unit continues to glow inside, creating the illusion of normal operation, but the lack of cold quickly leads to spoilage of food.
Understanding the principle of operation of the electrical circuit will help you determine whether the problem can be fixed on your own or whether you need to call a technician. Often the reason lies in protective mechanisms that turn off the motor to avoid overload. However, ignoring the symptoms can lead to expensive repairs or a complete replacement of the compressor.
In this article we will analyze in detail all the possible reasons why motor-compressor does not start, and will provide a step-by-step algorithm of actions. You'll learn how to test the start relay, thermostat, and wiring without much technical knowledge. The main thing is to act consistently and observe safety precautions when working with electricity.
Primary diagnostics and external factors
Before grabbing the tools, it is necessary to eliminate the elementary reasons for stopping the equipment. Often, users begin to panic, forgetting to check things such as whether there is electricity in the outlet or the position of the temperature control. If the refrigerator does not turn on, start with a visual inspection and check the power supply.
Make sure that the plug sits tightly in the socket, and the cable itself has no visible damage, kinks or traces of melting. Try plugging in another device, such as a kettle or lamp, into the same outlet to prevent a break in the wiring in the wall. Sometimes the problem lies in the surge protector itself or the extension cord, which could have failed.
Particular attention should be paid to the temperature regulator. On some models, the mechanical thermostat may have accidentally moved to the "Off" or "0" position. If you have electronic controls, check to see if the demo or "vacation" mode is activated, which simulates operation without cooling. It is also worth inspecting the door seal: if it does not fit tightly, the compressor may run idle or turn off frequently.
⚠️ Attention: If you notice a burning smell or sparking in the area of the outlet, immediately stop trying to turn it on and call an electrician. Operation of faulty wiring can lead to a fire.
Checking the starting relay and protective device
One of the most common reasons the compressor does not startis a malfunction of the starting relay. This small element is responsible for sending an impulse to the motor winding to start it into operation. If the relay is “stuck” in the open position or burned out, the motor simply will not receive a command to start, although electricity will flow to it.
To diagnose, you need to disconnect the refrigerator from the network, find a black cylindrical or rectangular block (compressor) on the back wall and remove the casing. Carefully disconnect the relay, which usually simply slides onto the motor contacts. Visually inspect the housing: the presence of cracks, burning or melted plastic indicates the need for replacement. There may be a copper core inside that must move freely; if it is jammed, the mechanism will not work.
How to check the relay with a multimeter?
For accurate diagnostics, use the tester in continuity mode. The resistance between the contacts should be zero or close to it. If the device shows a break or infinity, the part is faulty and requires replacement with a similar marking.
It is also important to check the thermal release, which is often built into the same structure as the starting device. It protects the windings from overheating. If the bimetallic strip inside is deformed, the circuit will be broken permanently. Replacing these components is one of the simplest procedures in refrigerator repairthat you can do it yourself.
- 🔌 Disconnect the unit from the power supply before removing any parts.
- 🔍 Shake the relay: if you hear a ringing inside, the core may be broken.
- 🧹 Clean the contacts from oxides and carbon deposits before installing a new relay.
Malfunctions of the thermostat and sensors
The thermostat (thermostat) is the “brain” that decides when to turn on the cooling. If it is faulty, it may simply not complete the circuit, even when the chamber is warm. In older models with mechanical control, failure of the capillary tube or contact group leads to an increase in temperature. the refrigerator does not respond. to an increase in temperature.
In modern models with a system No Frost and electronic control, air sensors are used instead of a thermostat. Their readings are read by the control module. If the sensor “lies” or shows a break, the board will not give the command to start the compressor. Often the problem is solved by replacing the sensor, but sometimes flashing or repairing the controller itself is required.
You can check a mechanical thermostat by closing its contacts directly (a temporary measure for testing). If the compressor starts working when it closes, then the problem is in the regulator. For electronic systems, diagnostics are possible only with the help of special equipment that reads error codes from the display or indicators.
It is worth noting that in some cases the thermostat is working, but its sensitive element (capillary) has shifted in the chamber and is not in proper contact with air. Check the mounting of the sensor inside the refrigerator compartment. The operation is also affected by the condition of the wiring running from the door to the body, which often frays when opened frequently.
Problems with the motor-compressor
The most expensive scenario is the failure of itself motor-compressor. This is the heart of the refrigerator, and if it has stopped, it will not be possible to restore the cold using conventional methods. The engine may not turn on due to inter-turn short circuit of the windings or mechanical jamming of the piston group.
You can identify a burnt-out motor by a characteristic sign: when you try to start it hums for a few seconds, then the relay clicks and everything goes quiet. In this case, the engine housing itself can become very hot. If the windings are “pierced” to the housing, the multimeter will show a short circuit between the terminals and the metal body of the compressor.
| Symptom | Probable cause | Solution |
|---|---|---|
| Silent, no buzzing | Open circuit, relay, thermostat | Replacing the starter or sensor |
| Buzzing, clicking, does not start | Stuck, low voltage | Replacing the compressor or relay |
| Works continuously without shutting down | Freon leakage, wear | Refilling or replacing the unit |
| The housing gets very hot | Overload, short circuit | Urgent electrical repair |
A mechanical “wedge” often occurs after a long period of equipment downtime. The oil in the crankcase thickens and the pistons cannot turn. In some cases, technicians manage to “unwedge” the compressor by applying increased voltage to the starting winding, but this is a risky procedure. Most often, a complete replacement of the unit is required, followed by evacuation and refilling the system with refrigerant.
⚠️ Attention: Replacing the compressor yourself requires special tools (burner, vacuum cleaner, pressure gauges). Without experience, there is a high risk of damaging the system or getting injured from high pressure.
Clogged capillary tube and leakage of freon
Although these problems are not directly related to the engine's electrical system, they affect its operating mode. If a blockage occurs in the system (for example, due to moisture or oil breakdown products), the pressure at the outlet of the compressor increases sharply. The motor tries to push freon, hums, overheats and turns off the thermal protection relay. refrigerant circulation a blockage has occurred (for example, due to moisture or oil breakdown products), the pressure at the outlet of the compressor increases sharply. The motor tries to push freon, hums, overheats and is turned off by the thermal protection relay.
Refrigerant leak is another common cause. When there is little gas in the system, the compressor runs idle, without creating the required pressure. The electronics may regard this as an emergency and block the start, or the engine will turn on for short periods of time without having time to cool the chambers.
☑️ Signs of problems with the refrigerant
It is visually difficult to diagnose a leak or blockage. Often it is necessary to open the system, pressurize it with nitrogen and search for the location of the damage. If you notice that the refrigerator turns on, works for 10-15 minutes, then turns off for a long break, and at the same time there is heat inside, this is a classic sign of a violation of the refrigerant circulation.
Failures in the electronic control module
In modern models, the electronic control module is responsible for turning the compressor on and off. This is a “think tank” that analyzes data from all sensors. If the triacs on the board that control the motor burn out, or there is a failure in the logic circuit, there will simply be no command to start.
The reasons for module failure are varied: power surges in the network, moisture ingress during defrosting, factory defects, or simply aging of components. Visually, you can see blackening, swollen capacitors, or traces of corrosion on the board. However, often an apparently serviceable board ceases to perform its functions.
Module repair is possible only in a specialized workshop where there are circuits and equipment for component soldering. At home, you can only check the integrity of the fuses or resolder obvious defects if you have the skills of a radio amateur. It is often easier and more reliable to replace the module with a new one.
Frequently asked questions (FAQ)
Why does the refrigerator click but does not turn on?
The starting relay usually makes a clicking sound when trying to start the engine. If the click is followed by a hum and a second click (shutdown), it means that the compressor cannot turn over (jamming) or the relay itself is faulty. If there is a click, but the motor is silent, the problem is a broken circuit or burnt out windings.
Is it possible to knock on the compressor to make it work?
This “folk” method sometimes helps if the pistons are slightly stuck after a long period of inactivity. A slight blow can move the mechanism. However, if there is a serious mechanical breakdown inside, the shocks can completely kill the compressor. Use this method only as a last resort.
How long should the compressor normally run?
The operating time depends on the load, room temperature and refrigerator model. Typically the operating cycle ranges from 10 to 30 minutes, followed by a pause. If the motor runs without stopping for hours or turns on too often (every 2-3 minutes), this is a sign of a malfunction.
Does the voltage level in the network affect starting?
Yes, at low voltage (below 190-200 Volts) the engine power may not be enough to start, especially if it is loaded. The motor will hum and heat up until the thermal protection operates. In such cases, it is recommended to use a voltage stabilizer.