A sudden stop of the compressor, lack of cold in the chamber and a characteristic click followed by silence often indicate a failure of the start relay. This small element is responsible for starting the electric motor and protecting it from overloads, so its breakdown completely paralyzes the operation of the unit. Owners of household appliances often wonder whether it is possible to make a replacement themselves or whether it is better to call a technician.
Removing the start relay is one of the most accessible procedures in self-repair of refrigeration equipment, which does not require complex special tools or deep knowledge of electrical engineering. However, like any work with electrical devices, it requires compliance with safety rules and attention to detail. Incorrect actions can lead to damage to the compressor windings or electric shock.
In this material we will analyze in detail the algorithm of actions that will allow you to carefully dismantle the faulty part, check its condition and install a new component. You will learn about the nuances of the design of different types of relays, diagnostic methods and typical mistakes that beginners make when first getting acquainted with the internal structure of the refrigerator.
Fault diagnosis and signs of breakdown
Before you start disassembling the unit, you need to make sure that the problem lies precisely in the starting device, and not in the compressor itself or the control system. The main symptom of the malfunction is the cyclic turning on of the motor: it hums for a few seconds, then a click is heard and the engine stops. After some time, the cycle repeats, which indicates that the thermal protection has tripped due to the impossibility of starting the rotor.
Visual inspection can also provide important clues. If traces of burning, melted plastic or black spots are visible on the relay body, then the part definitely requires replacement. Sometimes the cause of a failure is not an internal breakdown of the contacts, but oxidation of the terminals or a violation of the integrity of the supply wires, so the external inspection must be thorough.
For a more accurate diagnosis, professionals use a multimeter, checking the integrity of the windings and the resistance of the contacts. If you hear a knocking noise when you swing the relay next to your ear, this is a sure sign of destruction of the core or contacts inside the case, which makes further operation impossible without repair.
- 🔊 The compressor hums for 5-10 seconds, then a click follows and turns off.
- 🌡️ The temperature in the refrigerator and freezer compartments rises, the products begin to deteriorate.
- 🔥 On the back wall in the area of the motor, intense heat is felt or smoke is visible.
- ⚡ When turned on, the circuit breaker is knocked out or the plugs burn out.
⚠️ Attention: If after clicking the compressor continues to hum quietly and does not turn off anymore 20 seconds, immediately unplug the power cord. Working in this mode will lead to burnout of the electric motor windings in a matter of minutes.
It is important to distinguish a relay breakdown from problems with the compressor itself. If after replacing a working part the situation does not change, the mechanical part of the motor may have jammed or an interturn short circuit has occurred. In such cases, independent repair becomes impossible and requires the intervention of service center specialists.
Necessary tools and safety measures
To successfully dismantle the start relay, you do not need a complex professional tool. The entire set can be found in any home craftsman's drawer. The main requirement for the tools is serviceability and safety, especially when it comes to insulating the handles of screwdrivers and pliers.
The first and most important stage of preparation is to completely de-energize the refrigerator. It is not enough to simply turn off the button on the control panel; you must physically remove the plug from the socket. This will eliminate the risk of electric shock, since when removing the relay, the contacts may be exposed, and the capacitors in the circuit may retain charge.
For ease of operation, it is recommended to move the refrigerator away from the wall, providing access to the back from all sides. If the unit is heavy, it is better to call an assistant so as not to damage the floor covering or tear your back. It is also worth preparing a container for draining condensate if it has accumulated in the tray above the compressor.
- 🔧 Phillips and flathead screwdrivers for removing fastening screws and terminals.
- 🗑️ Pliers or pliers for clamping contacts and removing spring clips.
- 🧤 Dielectric gloves for additional protection when working with electrical equipment.
- 📱 Smartphone with a camera for photographing the connection diagram before disassembling.
☑️ Preparation for repair
Particular attention should be paid to lighting the work area. The back of the refrigerator is often covered in a layer of dust and cobwebs, so good light will help to avoid mistakes and to avoid losing small fasteners. It would be a good idea to prepare a vacuum cleaner to clean the space around the motor before starting work.
Access to the compressor and removal of the protective casing
The start relay is always located in the lower rear part of the refrigerator, directly on the compressor housing. To get to it, you need to remove the protective casing, which can be a metal or plastic cover secured with screws or latches. The design of the casing depends on the model and manufacturer of the refrigeration unit.
In some models, for example, Indesit or Ariston, the casing can be combined with a condensate collection tray. In this case, the tray is first carefully removed, often requiring the unscrewing of a couple of screws. In refrigerators LG or Samsung access can be achieved through a removable panel on the back wall, which needs to be snapped or unscrewed.
After removing the external barriers, you will see a black cylindrical or pear-shaped cylinder - this is the compressor itself. On its side or bottom there is a terminal box, closed with a plastic or metal cap. It is inside this assembly that the desired starting relay is located along with the thermal protector.
⚠️ Attention: Do not use excessive force when removing the casing. Plastic becomes brittle over time and may burst. If the screws do not come out, try preheating them with a hairdryer or using a penetrating lubricant.
Before touching the wires, be sure to take a photo of the connection. The color marking of wires may differ from one manufacturer to another, and memory is an unreliable assistant in this matter. The photo will become your insurance during assembly, allowing you to accurately connect all the contacts back.
Algorithm for dismantling the starting relay
The process of removing the relay depends on the type of its fastening, but the general principle remains unchanged. The device fits onto three contact pins extending from the compressor housing and is secured either with a spring clip or plastic latches. Your task is to release the latch and carefully pull the part down.
If the relay is secured with a metal bracket, it must be squeezed with pliers or gently pressed out with a flat-head screwdriver. Be careful not to scratch the compressor housing or damage the insulation of suitable wires. After removing the cap, the relay becomes free, but still sits tightly on the contacts.
To remove it from the contacts, take the relay with your hand by the body and pull it down with light rocking movements from side to side. Don't pull the wires! This can lead to their breakage at the base or damage to the internal contacts. If the relay is not removed, you can slightly warm up its seat with a hairdryer, since the plastic could “stick” over time.
Sequence of actions:1. Disconnect the wire connectors from the relay.
2. Remove the fixing bracket or release the latches.
3. While rocking, remove the relay from the contact pins of the compressor.
4. Remove the thermal relay (if it is separate).
In some designs, typical of older models Zil or Biryusa, the starting and thermal relay can be combined in one housing or have a specific form of fastening. It is important to remember the orientation of the parts relative to each other. Sometimes it is necessary to remove an additional insulating washer or bushing.
What to do if the relay is stuck?
If the relay cannot be removed in the usual way, do not use force. Try to carefully pry the housing with a flat screwdriver at the junction with the contact group, slightly loosening it. You can use WD-40 spray, but make sure that the liquid does not get inside the compressor contacts.
Types of relays and their design features
Understanding the type of installed relay will help you correctly replace it and select an analogue. Modern refrigerators most often use posistor (PTC) relays, which operate silently and have no moving parts. They are a ceramic disk that changes resistance when heated by current.
Older models use electromagnetic relays with a movable core. When voltage is applied, the core is drawn into the coil and closes the contacts, starting the engine. After the rotor accelerates, the current drops, and the core, under the influence of gravity or a spring, drops, opening the starting circuit. Such relays are sensitive to the position of the refrigerator.
There are also combined devices where the start-up and thermal protection functions are combined in one housing. They are more compact, but also more expensive to replace. When purchasing a new part, it is important to pay attention not only to the appearance, but also to the markings, engine power and bore diameter.
| Relay type | Principle of operation | Characteristic features | Examples of brands |
|---|---|---|---|
| Electromagnetic | Retraction of the core by current | Clicks during operation, sensitivity to tilts | Donbass, old Indesit |
| Posistor (PTC) | Change in ceramic resistance | Quiet, reliable, insensitive to position | LG, Samsung, Bosch |
| Combined | Combined start and protection | Compact, difficult to select analog | Whirlpool, Ariston |
| Thermal (separate) | Opening with a bimetallic plate | Often paired with a starter, protects against overheating | All types of refrigerators |
When choosing a spare part, be sure to check the markings on the body of the old relay. Even if the new device looks identical in appearance, the difference in operating current or rod diameter can lead to unstable operation of the compressor. It is critical that the rated current of the new relay matches the power of your compressor, otherwise the protection will not work in the event of an overload.
Checking the functionality of the removed device
After After dismantling the relay, it is advisable to check it to finally verify the cause of the breakdown. For electromagnetic devices, it is enough to shake the relay near your ear: if you hear the ringing of broken contacts or the knock of a torn core, the part is clearly faulty. A visual inspection for contact melting is also required.
Checking a posistor relay requires the use of a multimeter. In a cold state, the resistance between the contacts should be in the range of 10-60 Ohms. If the device shows infinity (open) or zero (short circuit), the posistor has burned out and requires replacement. Also check that there is no short circuit to the housing.
The thermal relay is checked by checking the contacts: in normal condition the circuit should be closed. You can gently heat the relay body (for example, with a hairdryer or a soldering iron through the metal), and after a while the contacts should open with a click. After cooling, the circuit should recover again.
- 🔍 Visual inspection: look for traces of soot, cracks and melting.
- 🔊 Acoustic test: shaking to identify internal damage.
- 📟 Resistance measurement: checking compliance with nominal values.
- 🔥 Heating test: checking the function of opening the circuit when overheating.
⚠️ Attention: If you are not confident in your knowledge of electrical engineering or you do not have a multimeter, it is better not to risk it and replace the relay with a new one. The cost of the part is low, and the risk of erroneous diagnosis can lead to the purchase of an unnecessary compressor.
Sometimes the cause of failure is not the relay itself, but oxidation of the contacts at the compressor terminals. Cleaning the contacts with fine sandpaper or alcohol can restore system functionality even with an old relay, if it is still usable.
Installing a new relay and testing the system
Installing a new starting relay is done in the reverse order of removal. Carefully push the device onto the contact pins of the compressor until it stops. Make sure that the relay is seated tightly and evenly, without distortion. If using a retaining bracket, secure it in place.
Connect the wires according to the photo or color code you took earlier. Typically, the blue wire goes to one pin, the brown or black wire to the other, and the ground (yellow-green) is attached to the case. After connecting, check the reliability of all connections again.
Reinstall the protective casing and condensate tray, securing them with screws. Make sure that no wires are pinched or touching hot parts of the compressor or moving parts (if there is a fan). Only after complete assembly can you plug in the refrigerator.
The first startup after replacement may be accompanied by an unusual sound or longer operation of the compressor. This is normal, since the system needs time to build up pressure and reach operating mode. During the first 2-3 hours, do not open the doors of the refrigerator so that it can gain temperature.
If after switching on the refrigerator works like new, then the repair was successful. If the symptoms persist, the problem may lie deeper - in the motor windings, heat dissipation system or electronic control module. In this case, further diagnostics require professional equipment.
Is it possible to temporarily start a refrigerator without a starting relay?
Theoretically, you can start an asynchronous motor manually by short-circuiting the starting winding, but this is strictly not recommended. This is life-threatening, can lead to a fire and is guaranteed to damage the compressor due to the lack of overload protection. Operating a refrigerator without a relay is unacceptable.
Why does a new relay burn out after a few days?
Most often this indicates problems with the compressor itself: an interturn short circuit, jamming of the piston group or a grounding failure. The cause may also be unstable voltage in the network or an incorrectly selected current characteristic of the new relay. An in-depth diagnosis of the motor is required.
What is the difference between relays for No Frost and drip refrigerators?
There is no fundamental difference in the types of relays for these systems, since they depend on the compressor model, and not on the defrosting system. However, in No Frost refrigerators, compressors may start more often, so the requirements for relay life may be higher. Always rely on the markings.
Where can I find the markings for selecting an analogue?
The markings are applied directly to the housing of the starting relay (for example, RT, 33.6, PTC). Information can also be found in the technical documentation of the refrigerator or on the compressor nameplate, where its power is indicated. Using this data, the store will select a compatible part.
Is it dangerous to change the relay yourself if the refrigerator is under warranty?
Yes, it is dangerous in terms of losing the warranty. Any interference with the electrical circuit or removal of seals from the compressor will automatically void the manufacturer's warranty. If the warranty period has not expired, contact an authorized service center.