A sudden stop in the operation of a refrigeration unit often takes you by surprise, especially when there are perishable products in the chambers. In most cases, the cause of failure is the failure of start relay a small but critical element of the electrical circuit. This component is responsible for starting the compressor motor and its further operation, and if it burns out, the refrigerator simply stops cooling, although the light inside may continue to be on.
Understanding where exactly this unit is located is the first step to self-diagnosis and repair, which can save a significant amount of money on calling a technician. The location of the part may vary depending on the make and model of your refrigerator, be it Indesit, Beko or LG, however, the general principle of the layout remains similar for most household appliances.
In this article we will examine in detail the design of the rear walls, methods of safe access to the compressor and an algorithm of actions when a malfunction is detected. The starting relay is always attached directly to the side of the compressor, covering the contacts of the motor windings. It is important not only to find it, but also to correctly identify the type of breakdown so as not to make a mistake when restoring the operation of the equipment.
Functional purpose and principle of operation of the unit
The starting relay is an electromechanical switch that supplies voltage to the starting winding of the compressor engine only at the moment it starts. As soon as the motor rotor reaches the required speed, the relay opens the starting winding circuit, and the engine continues to operate on the main winding. If this mechanism does not work, the compressor will hum, but will not start, or will constantly click, trying to start.
In modern models, posistor relays are most often used, where the role of a switch is played by a temperature-sensitive element - a posistor. When current is applied, it heats up, its resistance increases sharply, and the starting winding circuit breaks. In older units there are induction devices that operate on the principle of an electromagnetic field created by the current in the working winding. Compressor It cannot work without a working relay, since the torque of the working winding alone is not enough to start under freon load.
Failure of this component often confused with a breakdown of the motor itself, which leads to unnecessary expensive repairs. However, statistics show that replacing the relay helps restore the operation of the equipment in 80% of cases when the compressor hums but does not start. It is important to understand the difference between a thermal protection relay (which stands alone or in the same housing) and a starting one, although in modern compact units they are often combined into a single design.
- 🔌 Provides high starting current to the starting winding of the motor.
- 🛑 Automatically turns off the starting winding after acceleration rotor.
- 🛡️ Protects the engine from overloads and overheating (in combined models).
It is worth noting that the resource of this element is limited by the number of on and off cycles. Frequent power surges in the network can significantly shorten the service life of a posistor, causing its premature destruction or loss of contact properties. That is why, to extend the life of the refrigerator, it is recommended to use voltage stabilizers, especially in houses with old wiring.
Location of the component: where to look on different models
To find the start relay, you need to gain access to the lower rear part of the refrigerator. In the classic layout, the compressor unit is located in a niche under the main body, hidden from view by a metal or plastic casing. You will need to move the refrigerator away from the wall, providing free access to its back, and remove the protective cover, which is usually secured with latches or several screws.
After removing the cover, you will see the compressor - a black metal "tank" from which copper tubes and electrical wires extend. The start relay is always located on the side of this cylinder, often at the bottom. It looks like a plastic box (black, white or gray) placed directly on three pins protruding from the motor housing. On different models, such as Atlant or Stinol, the shape of the relay housing may differ, but the principle of fastening remains unchanged.
⚠️ Attention: Before any manipulations with electrical components, be sure to unplug the refrigerator! Staying energized even after being unplugged from the socket in capacitors can be dangerous, although the risk is minimal, it is better to be safe.
Sometimes access to the relay may be difficult due to the dense arrangement of the tubes or the presence of an additional tray for collecting condensate. In some models Samsung or Electrolux it may be necessary to also remove the lower decorative panel if it blocks the view. The main thing is not to use excessive force, so as not to damage the copper lines, which are very soft and easily deformed.
Removal and visual diagnosis of the fault
The process of removing the start relay is quite simple and does not require a special tool, except perhaps a flat-head screwdriver. After turning off the power and removing the protective cover of the compressor compartment, carefully inspect the side of the motor. You will see a plastic block that holds the wires. To remove it, you need to gently rock it from side to side while pulling it towards you. In some cases, it may be necessary to pry off the housing with a screwdriver, but this must be done extremely carefully.
After removing the device from its seat, perform an initial visual inspection. The housing must not have any traces of melting, soot or mechanical damage. If you see blackened plastic or smell a burning odor, then diagnostics the element is burnt out. It is also worth checking the condition of the internal contacts if the design allows you to look inside without destroying the case.
Often the fault is visible to the naked eye: inside the plastic box there may be a charred posistor or melted springs. In induction relays, a broken coil or a jammed movable core may be visible. If the relay looks intact externally, this does not guarantee its serviceability, and a more in-depth check using a multimeter will be required.
- 👀 Inspect the case for cracks, melts and traces of burning.
- 👃 Smell the part - the smell of burnt plastic indicates overheating.
- 🔊 Shake the relay near your ear: a dull knock may mean destruction of the internal elements.
It is important to remember the orientation of the relay before completely removing it, so that when installing a new part you do not confuse the position of the contacts. Although many models are structurally symmetrical, it is better to play it safe and take a photo before removing the wires. This will simplify reassembly and eliminate connection errors.
Compatibility table and relay types
When selecting spare parts, it is important to consider not only the brand of the refrigerator, but also the type of compressor, since starting relays are not universal. They differ in motor power, connection type (induction or posistor) and contact configuration. Using an unsuitable relay can lead to repeated breakdown or even burning of the compressor windings.
Below is a table to help you navigate the main types of devices and their compatibility with various brands of equipment. However, it is always better to compare the markings on the body of the old part with the new one before purchasing.
| Relay type | Principle of operation | Compatible brands | Characteristic features |
|---|---|---|---|
| Posistor (RTK) | Thermal (chip heating) | Indesit, Ariston, Beko, Samsung | Plastic case, ceramic element inside |
| Induction (RTP) | Electromagnetic field | USSR refrigerators, old models | Metal or heavy plastic case, coil |
| Combined | Start + Thermal protection | LG, Whirlpool, Electrolux | Larger size, two separate blocks in one |
| Universal | Posistor | Suitable for many models (replacement) | Often comes complete with adapters for different bases |
When choosing a replacement, pay attention to the current characteristics. The housing is usually stamped with numbers, such as 1/4 HP or 1/5 HP, which indicates the engine power. If you install a relay designed for less power, it will constantly overheat and turn off. If it is too large, the starting winding may not open, which will lead to engine combustion.
Checking performance with a multimeter
If visual the inspection did not reveal any obvious defects, it is necessary to carry out an electrical test using a multimeter. This will allow you to accurately determine whether there is an open circuit or short circuit inside the device. To carry out the test, switch the device to the resistance measurement mode (Ohm) and touch the relay contact groups with the probes.
In a working posistor relay, the resistance between the contacts should be low (several Ohms) in a cold state. Some time after applying voltage (or heating with a hairdryer), the resistance should increase sharply to infinity. If the device shows “infinity” immediately or “zero” constantly, the part is faulty. For induction relays, the integrity of the coil and the mobility of the core are checked.
It is also worth checking the thermal protection relay if it is built into one unit. Its contacts should ring when cold (resistance is close to zero). When heated (you can gently heat it with a lighter without overdoing it), the circuit should open. Lack of response indicates the need to replace the entire assembly.
⚠️ Attention: Be careful when testing with a multimeter under voltage if you do not have the skills of an electrician. It is better to carry out resistance diagnostics only on a device that is completely disconnected and disconnected from the wires.
A common mistake is to try to “reanimate” a burnt out relay by stripping the contacts or temporarily closing the circuit. This is strictly forbidden, as this will lead to a direct start of the engine without protection, which is guaranteed to damage the compressor in a matter of minutes.
☑️ Relay diagnostics
Replacement of the part and assembly of the system
Process Installing a new start relay is the opposite of dismantling, but requires care. Make sure that the new part fully matches the removed one in terms of seats and number of contacts. Push the relay onto the three pins of the compressor as far as it will go, making sure it is seated snugly and evenly. Distortions are unacceptable, as this can lead to poor contact or breakage of the ceramic posistor inside.
Next you need to connect the wires. If you took a photo, simply reproduce the diagram. If not, be guided by the colors and markings. Typically, the phase wire goes to one contact, and the neutral or ground wire goes to the others. In some circuits, there is a separate wire for the condenser fan, which also needs to be connected correctly. Installation must be made reliably so that the vibration of the compressor does not break the contact.
After connecting all the wires, secure the relay in its normal place (if there is a bracket or clamp) and install the protective cover in place compressor compartment cover. Only after complete assembly turn on the refrigerator. The first start may be accompanied by a longer hum, but after a few seconds the engine should return to operating mode and start refrigerant circulation.
- 🔧 Install the new relay on the compressor pins until it clicks.
- 🔌 Connect the wires according to the diagram or photograph.
- 🔩 Secure the clamps and install the protective cover.
- 🔌 Plug in the device and listen to the operation of the motor.
If after turning on the compressor started running smoothly, without unnecessary sounds, and after 10-15 minutes cold appeared in the chambers, the repair can be considered successful. If the situation repeats (clicking, humming without starting), perhaps the problem lies deeper - in the compressor itself or the heat removal system.
What to do if the new relay also burned out?
If the new relay burned out immediately after installation, this may indicate an interturn short circuit in the compressor windings or problems with the voltage in networks. In this case, it is dangerous to continue operation.
Common mistakes during self-repair
Independent repair of refrigerators is a rewarding task, but beginners often make common mistakes that can aggravate the situation. One of the most common is neglecting to clean the capacitor (the black grill on the back) when replacing the relay. A condenser clogged with dust leads to overheating of the compressor, which triggers the thermal relay to operate and, as a result, overload the starting element.
Another mistake is installing the relay “at random”, without checking the contacts. Oxidized or burnt terminals on the compressor itself can cause poor contact, sparking and repeated failure of even a new part. Before installing a new relay, it is recommended to carefully clean the contact pads on the motor with fine sandpaper or alcohol.
Also, do not forget about vibration. If the relay is not secured tightly enough or the wires are tense, the constant vibration of a running motor will lead to broken contacts. All connections should have a little extra wire length, but not dangle loosely, touching hot parts of the compressor or sharp edges of the housing.
⚠️ Attention: Do not attempt to repair or open a sealed compressor. All work is limited only to attachments (relays, thermostats, fans). Opening the motor requires special equipment and skills.
Remember that if after replacing the relay the refrigerator works, but cools poorly or does not turn off for a long time, there may be a freon leak. In this case, replacing the electrics will not help, and you will need to call a technician with equipment to find leaks and refill the refrigerant.
FAQ: Frequently asked questions
Is it possible to start a refrigerator without a starting relay?
Theoretically, you can start the engine manually by briefly applying current to the starting winding, but this is extremely dangerous and impractical for domestic use. Without a relay, the compressor will not be able to operate in automatic mode, will overheat and quickly fail. Operating a refrigerator without a working relay is impossible.
How much does a starting relay cost and is it difficult to find?
The cost of a relay varies from 500 to 2000 rubles, depending on the model and manufacturer. You can find them in spare parts stores for household appliances, at radio markets, or order online according to the markings. Universal Chinese analogues are cheaper, but may be inferior in reliability to the originals.
Why does the relay burn out repeatedly (constantly)?
Frequent burning of the relay indicates a systemic problem: it could be an unstable voltage in the network, a malfunction of the compressor itself (stiff running, interturn short circuit) or poor contact in the circuit. Also, the cause may be a clogged condenser, causing overheating of the entire system.
Is the relay different for a two-compressor refrigerator?
Yes, in two-compressor models (where the freezer and refrigerator are separate), each compressor has its own starting relay. They can be the same or vary in power, depending on the volume of the chambers. They need to be replaced separately, diagnosing the faulty unit.
Does the system need to be evacuated when replacing the relay?
No, the start relay is replaced without opening the freon circuit. The tightness of the system is not compromised, since you are working only with the electrical part. Evacuation and refilling are required only when repairing tubes or replacing the compressor itself.