A sudden stop of the compressor is always stressful for the owner, because the safety of the products and the operation of the entire unit are at stake. If you notice that Indesit refrigerator it hums, but does not produce any cold, or the motor tries to start and immediately clicks, the problem most likely lies in the start protection relay. This small component plays the role of a “starter” for the engine, providing the necessary starting torque and protecting the windings from overloads.
Replacing this part independently is a task quite feasible for a person with basic skills in working with electricians and a screwdriver. You do not need complex industrial equipment; a minimal set of tools and a clear understanding of the device circuit will be enough. However
In this article we will analyze in detail how to determine a fault in the relay, what types of these devices exist in technology Indesit and how to properly replace it so that your refrigerator works like new again. We will look at the connection nuances for different engine modifications and answer frequently asked questions that arise during the repair process.
⚠️ Attention: Before starting any repair work, be sure to disconnect the refrigerator from the electrical network. Working with live wiring is deadly and can lead to a short circuit.
Diagnosing a faulty start relay
Before running to the store for a new part, you need to make sure that the problem lies in the relay, and not in the compressor or thermostat itself. The symptoms may be similar, but the approach to repair is radically different. Primary diagnostics helps to avoid purchasing unnecessary spare parts and wasting time disassembling working components.
One of the most obvious signs of a malfunction is a characteristic click that is heard every few minutes. The engine tries to start, hums, but after a couple of seconds there is a click and the hum stops. This means that starting relay cannot close the starting winding circuit or the thermal protection is triggered due to lack of rotor rotation. If the motor is hot to the touch, this confirms that there is a problem in the starting circuit.
Another scenario is complete silence. The compressor does not make any sounds, the light inside is on, but there is no cold. In this case, it is possible that the contacts inside the relay have oxidized or become “stuck” when open, or the thermal protection has burned out. It is also worth checking whether the relay armature is mechanically blocked, which often happens during prolonged use or moisture.
- 🔊 Cyclic clicks: The motor hums for 3-5 seconds, then clicks and pauses (often repeated).
- 🔥 Case heating: The compressor heats up, but does not start, which indicates operation thermal protection.
- 🔇 Lack of response: The refrigerator is on, there is light, but the compressor is completely silent.
- ⚡ Knocking out plugs: A short circuit inside the relay can lead to the operation of the circuit breakers in the panel.
For more accurate diagnostics, you can carefully remove the relay from the compressor (after turning off the power) and shake it near your ear. If you hear a ringing or knocking noise inside, like breaking glass, then the internal coil or contacts are damaged. In solid-state models, this method does not work; continuity testing with a multimeter is required.
Types of relays used in Indesit refrigerators
Brand equipment Indesit Over the years of production, it has been equipped with various types of compressors, from Italian ones Aspera (previously Danfoss) to more modern analogues. Accordingly, starting devices may differ in design. Understanding the type of relay you have is critical to choosing the right replacement.
The most common electromagnetic relays are the posistor type. In them, the start occurs due to a sharp change in the resistance of the ceramic element (posistor) when heated by current. Such models are often marked PTK or PTC. They are reliable, have no moving parts inside the plastic case, but are sensitive to voltage surges.
The second type is classic induction relays with a moving core. Inside there is a coil and a spring-loaded core, which, when starting, closes the contacts of the starting winding. Such devices are more often found on older models of refrigerators and compressors with low starting torque. They are noisier in operation and have a limited service life of mechanical parts.
⚠️ Attention: Relays from different manufacturers (for example, Indesit, Ariston, Stinol) can be interchangeable only if the electrical parameters and seat geometry match. Do not rely only on appearance.
When choosing a new part, pay attention to the markings on the body. The key parameters are voltage (usually 220V), frequency (50Hz) and, most importantly, the motor power for which the relay is intended. Using a relay with an inappropriate power range may result in the compressor either not starting or the winding burning out.
Necessary tools and preparation for work
Replacing a relay does not require calling a technician with complex equipment, the whole process can be done independently. However, for comfortable and safe work it is necessary to prepare the workplace and tools. Make sure in advance that you have access to the back wall of the refrigerator, which may require moving the appliance away from the wall.
The main tool you will need is a flathead and Phillips screwdriver. You will use them to remove the protective casing and unscrew the terminals. You may also need pliers or side cutters to carefully remove old contacts if they have become stuck. To check the serviceability of a new part, a multimeter will not be amiss, although experienced craftsmen often do without it, relying on visual inspection and marking.
An important stage of preparation is to ensure good lighting. The compressor area is often darkened and the markings on the relay are small. Use a flashlight or portable lamp. Also prepare a dry rag to clean the contacts from dust and oxides, since dirt can cause repeated breakdowns.
☑️ Preparation for repair
Don't forget about gloves. Although we have turned off the voltage, there may be technical grease, dust and sharp metal edges inside the compressor compartment. Rubber gloves will also improve your grip on the tool if your hands become sweaty.
Step-by-step instructions for replacing the relay
The replacement process begins with removing the compressor protective casing. It is usually secured with latches or screws. Be careful, the plastic may have become brittle over the years of use. After removing the cover, you will see the compressor itself (the black “barrel”) and the box attached to it - this is our starting relay.
Remove the old relay. It is simply put on the three contacts of the compressor and secured with a bracket or clamp. Remember or take a photo of the position of the wires: which wire goes where. Typically there are two or three wires coming from the thermostat and the power cord. Disconnect them by first marking them with a marker or taking a photo.
Install a new relay. Make sure it is oriented correctly: the body often has an arrow UP or inscription TOPindicating the top position. The relay should sit tightly on the contacts of the compressor. If it dangles or does not fit completely, you have made a mistake with the model or installation side.
⚠️ Attention: When connecting wires, strictly follow the color markings or your diagram. By mixing up phase and zero, you may not start the motor or create a risk of electric shock when touching the housing.
After connecting the wires, reassemble the structure in the reverse order: install the metal clamp, put on the plastic casing. Plug in the refrigerator and listen. Startup should be smooth, without strong clicks or buzzing. If the engine starts and the cold starts, the repair was successful.
What to do if the new relay clicks but does not start the compressor?
If the situation has not changed when installing a new working relay, the problem may be deeper. Perhaps the compressor itself is jammed (mechanical failure), the motor winding is burned out, or the thermostat is faulty and does not supply voltage to the relay. In this case, more complex diagnostics are required with measuring the resistance of the windings.
Connection diagram and correspondence table
Correct connection of wires is the key to successful repairs. Depending on the type of relay (with a posistor or induction), the circuit may differ slightly in the number of contacts, but the principle remains the same. There are three contacts on the compressor housing, arranged in a triangle.
The upper contact is always the phase passing through the thermostat. The two bottom ones are the starting and working windings. The relay fits onto these pins, closing the starting winding circuit for a short time. It is important not to confuse the polarity of connecting the relay itself to the compressor terminals, although in most modern models it is physically impossible to do this incorrectly due to the shape of the case.
Below is a table of contact correspondence for a standard compressor Indesit (analog Danfoss/Secop), which will help you navigate the visual inspection.
| Contact location | Purpose | Wire color (typical) | Function in relay |
|---|---|---|---|
| Upper (S) | Start winding | Black / Red | Posistor / Start contact |
| Bottom left (R) | Working winding | White / Blue | Working contact / Thermal protection |
| Bottom right (C) | Common (Phase) | Brown / Black | Voltage input |
| Case | Grounding | Yellow-green | Flash protection |
Please note that wire colors may vary depending on the year of manufacture of the refrigerator and the country of assembly. Therefore, always focus primarily on the diagram drawn on the inside of the compressor compartment cover, if it has been preserved.
Common mistakes during self-repair
Even a simple operation can go wrong if important nuances are not taken into account. One of the most common mistakes is trying to install a relay “by force”. If the device does not slide onto the contacts with a slight movement of the hand, then you have chosen the wrong model or are oriented incorrectly. The use of force will lead to breakage of the ceramic posistor or deformation of the contacts.
Another mistake is ignoring the thermal protection state. Often it is built into the relay housing or mounted nearby. If you only change the starting part, but the thermal protection remains old and tired, the refrigerator may stop working again after a week. Change the assembly or make sure that all components are in good condition.
Also, beginners often forget to check the condition of the contacts on the compressor itself. If the pins are oxidized or burnt, the new relay will not make reliable contact. Clean them with fine sandpaper or a file before installing the new part. This will take a minute, but will extend the life of the repair.
- 🚫 Ignoring the "UP" marking: Installing the relay upside down will disrupt the operation of the posistor or core.
- 🚫 Twisting of wires: Connecting wires by twisting without soldering or terminals is unacceptable, this will lead to heating and fire.
- 🚫 Buying by eye: Relays for compressors of different capacities (L-series, T-series) are not interchangeable.
- 🚫 Lack of fixation: If the relay is not secured with a bracket, vibration the compressor will quickly loosen the contacts.
Remember that high-quality repair is not just replacing a part, but a comprehensive check of the unit. Pay attention to the cleanliness of the contacts and the reliability of the connections, and your Indesit refrigerator will serve for many years to come.
Questions and answers (FAQ)
Is it possible to start a refrigerator without a relay?
Theoretically, you can start a compressor without a starting relay by applying voltage directly to the starting winding for a short time, but doing this is strictly not recommended. This requires precise timing (fractions of a second) and carries a high risk of burning the motor winding or receiving an electric shock. A relay is a cheap part, it is dangerous to skimp on it.
Why does a new relay burn out immediately after installation?
If a new relay burns out instantly, the reason is most likely not in it. The problem may be in the compressor itself (turn-to-turn short circuit, wedge), in a faulty thermostat that supplies voltage too often, or in unstable mains voltage. It is also possible that a relay with the wrong power range was selected.
Where can I find the part number for a replacement relay?
The part number is usually stamped on the side or top edge of the plastic case. Look for type marking PTC 15-30 or type manufacturer codes Indesit C00123456. The number can also be found in the technical documentation of the refrigerator or on the manufacturer’s website according to the unit model.
Is the relay different for No Frost and drip system refrigerators?
In principle, the relays are the same, since they depend on the type of compressor, and not on the defrosting system. However, in No Frost systems, the load on the compressor may be higher due to more frequent switching cycles, so it is important to choose a relay with a power reserve that matches your motor.