Sudden stop compressor or characteristic clicks when trying to start the refrigerator often indicate a problem with the starting mechanism. If you are faced with the fact that the engine hums but does not start, or is completely silent, the first thing you need to check is start-up protection relay. This small but critical element is responsible for supplying voltage to the motor windings and protecting against overloads. Understanding exactly where it is located will allow you to carry out initial diagnostics or replace the part without calling a technician.
The location of this component may vary depending on the manufacturer and model of your equipment. In most modern units, such as Indesit, Atlant or LG, the relay is mounted directly on the compressor housing. However, access to it is often limited by the design features of the rear wall. In this material we will analyze in detail the search algorithm, types of location and nuances of dismantling for various types of refrigeration equipment.
Before you begin disassembling, make sure that you follow the basic rules of electrical safety. Any manipulations with electrical components should only be carried out with the device completely disconnected from the mains. This is not just a recommendation, but a mandatory condition, ignoring which can lead to electric shock or failure of the electronics.
Functional purpose and principle of operation
Start-protective relay performs a double function in the cooling system. Firstly, it provides a short-term voltage supply to the compressor starting winding to create the necessary torque to rotate the rotor. Secondly, thermal protection inside the relay opens the circuit when the current increases critically, preventing the motor from burning out. Without this device, starting a single-phase asynchronous motor would be impossible.
Inside the body of the part there is a movable core or posistor that responds to changes in current. When starting, the current is high, the contacts close and the engine starts. As soon as the rotor picks up speed, the current drops and the mechanism opens the starting circuit. If the motor is jammed or an overload occurs, the current does not drop, and the thermal plate opens the contacts, de-energizing the compressor. That is why troubleshooting often begins with checking this particular unit.
Modern models can use solid-state PTC relay (posistors), which do not have moving mechanical parts. They work by changing resistance when heated. Such elements are considered more reliable, but their search and replacement principle remains similar to classical inductive models. Understanding the type of your part will help in choosing the correct replacement part.
⚠️ Attention: A visually good relay may not work. Often the internal winding burns out or the bimetallic plate breaks, which is not always visible without “testing” with a multimeter.
General layout on the compressor
In 95% of cases, the answer to the question “where is the start-up relay located” lies on the back wall of the refrigerator. The compressor, which is a black metal cylinder, is the heart of the system. The relay is placed directly on the terminals (contacts) protruding from the motor housing. To see it, you need to move the refrigerator away from the wall and remove the back protective panel, if any.
At the end of the compressor you will see a plastic box in black, white or gray. This is the element you are looking for. It can be combined with a capacitor in one block or be a separate pad. Fastening is carried out due to a tight fit on the contacts and is sometimes fixed with a metal bracket or frame. Wires from the thermostat or control board come to the side of this block.
It is important not to confuse the relay with a capacitor. The capacitor usually has a cylindrical shape and is also located next to the motor, but it is not placed directly on the motor contacts, but is connected by wires. Start relay always has direct electrical contact with the compressor terminals. If you see a plastic box placed on three pins coming out of the metal, you have found the right part.
Instructions for accessing the relay in different models
The process of gaining access to the part may differ depending on the design of the rear panel. In old Soviet-made models or simple refrigerators, the panel is often secured with latches or screws around the perimeter. In more modern units, such as Biryusa And Saratov, the panel is often secured with latches or screws around the perimeter. In more modern units, such as Bosch or Siemens, it may be necessary to remove the additional plastic casing covering the engine compartment.
The action algorithm usually looks like the following way:
- 🔌 Disconnect the refrigerator from the power supply and move it away from the wall.
- 🔧 Unscrew the screws holding the back metal or cardboard panel.
- 👀 Visually inspect the lower part of the compressor - the relay is located at its end.
- 🛡️ If access is blocked by a plastic box, carefully remove it by snapping the latches.
In some models of refrigerators with a system No Frost the compressor may be partially covered with insulating material or have a complex suspension system. In such cases, force should not be used. Carefully study the design: sometimes it is necessary to remove the condensate tray, which is located directly above the motor. Care when removing the panels is important, as the plastic becomes brittle over time.
☑️ Check before removing the relay
Typical signs of a faulty part
You can understand that the problem lies in the relay by the characteristic symptoms. The most obvious sign is that the refrigerator does not turn on, the compressor is cold, but periodic clicks are heard. These clicks are produced precisely by the thermal protection of the relay, which is triggered due to the impossibility of starting the engine. The cycle may repeat every few minutes.
Another symptom is the motor humming for a few seconds, followed by a clicking sound and stopping. This indicates that the starting winding does not receive an impulse to start, or the engine itself is jammed. If the relay emits a burning smell or traces of soot are visible on the contacts, it must be replaced. Also, the strong heating of the relay housing during operation should also alert you.
Sometimes the refrigerator may work, but not reach the desired temperature, turning on for short periods of time. This may indicate “sticking” contacts or malfunctioning thermal protection, which prematurely de-energizes the compressor. The table below shows the main symptoms and their probable causes.
| Symptom | Probable cause | Action |
|---|---|---|
| Clicks, the motor does not start | The relay coil is burnt out or jammed compressor | Replacing the relay, checking the compressor |
| Humming for 5-10 seconds, then silence | The relay starting circuit is faulty | Diagnostics with a multimeter |
| Burning smell in the motor area | Overheating and melting of the relay housing | Urgent replacement of the part |
| The refrigerator turns off by itself | Thermal protection is triggered | Checking the load and relay |
⚠️ Attention: If after replacing the relay the symptoms repeat (it clicks again and does not start), the problem is most likely in the compressor itself (an interturn short circuit or wedge). Further attempts to start may permanently damage the motor.
Dismantling process and visual inspection
Removing the part does not require a complex tool. Usually a flathead screwdriver and pliers are sufficient. First you need to disconnect the block with wires that goes to the relay. It may fit tightly, so it should be gently rocked from side to side while holding the relay body with your other hand. Do not pull on the wires themselves, so as not to break them at the base.
The relay itself is removed by moving backwards, perpendicular to the compressor terminals. Sometimes it is fixed with a metal U-shaped bracket, which needs to be bent or removed. Be careful: inside the relay there may be a posistor or a moving mechanism, which can crumble if it hits the floor hard. If you plan to reuse the part (for testing), handle it with care.
When visually inspecting, pay attention to the condition of the contacts. If they are blackened, melted or covered with oxide, it is better not to install such a relay back. Also check the integrity of the plastic case. Cracks can lead to moisture ingress and short circuits. If a rattling sound is heard inside (as if from broken glass), it means that the ceramic posistor is destroyed and the part requires 100% replacement.
Is it possible to repair an old relay?
In theory, you can try to clean the contacts or replace the posistor with a similar one. However, in practice, the cost of a new part (usually 300-800 rubles) is not commensurate with the labor costs to repair the old one. In addition, the reliability of the restored element will be low, which threatens repeated failure of the expensive compressor.
Nuances of replacement and selection of analogues
When purchasing a new element, it is important to consider that start-protection relays are not universal. They are selected strictly according to the power and type of compressor. There are always markings on the body of the part, for example RKT, PTMR, 616106 and other codes. These numbers indicate series and compatibility. Using an unsuitable relay can result in the compressor either not starting or burning out due to untimely disconnection of the starting winding.
If you cannot find an original spare part with exactly the same markings, you can use universal kits or select analogues using compatibility tables. Such kits often include a set of adapter frames that allow you to install the relay on different types of terminals. However, it is best to look for a replacement using the code of the compressor manufacturer (for example, Danfoss, Secop, Embraco).
Installation is carried out in the reverse order of removal. The relay is pushed onto the contacts until it stops. It is important that it fits tightly and does not dangle. After connecting the wires and turning it on, listen to the operation of the motor. Starting should be soft, without loud clicks or buzzing. If the refrigerator starts working in normal mode and begins to gain temperature, the repair can be considered successful.
Frequently asked questions (FAQ)
Is it possible to start a refrigerator without a starting relay?
Theoretically, you can start an asynchronous motor by manually applying voltage to the starting winding, but you cannot hold it down all the time - the engine will burn out. Operating a refrigerator without a working relay is strictly prohibited, as this will lead to the compressor burning out in a matter of minutes.
How much does it cost to replace the relay in a service center?
The cost consists of the price of the part itself (usually from 300 to 1500 rubles) and the work of the technician. In service centers, visiting and diagnostics may cost additionally. Self-replacement saves money, since the procedure is technically simple and does not require special equipment.
Why does a new relay burn out after a short time?
A common cause is unstable voltage in the network or problems with the compressor itself (stiff running, wear of the mechanical part). Also, the relay can burn out if it is selected incorrectly (does not match the current). In rare cases, a faulty thermostat is to blame, which does not allow the motor to rest.
Where to buy an original starting relay?
It is better to look for original spare parts in specialized stores of spare parts for household appliances or from official dealers of brands. Markets and ordinary hardware stores often sell universal analogs that may be suitable, but require careful selection according to characteristics.