Finding the location start relay becomes a priority when the refrigerator stops turning on or makes a characteristic click, followed by a hum and shuts down. Understanding exactly where this small but critical element is located in the unit’s design allows you to save time on calling a technician or conducting initial diagnostics yourself. In most household models, this component is hidden from the user’s eyes, since it is directly related to the operation of the compressor.
The location of the part does not depend on the brand, be it Indesit, Atlant or LG, since the operating principle of single-compressor and double-compressor systems is standardized. To get to the desired unit, you will have to look into the back of the refrigerator, where all the main technical communications are located. It is there, in the lower third of the case, that the device you are looking for is usually hidden.
Before proceeding with disassembly, you must clearly understand that any manipulations with electrical components require first disconnecting the device from the network. The relay is located directly on the contact group of the compressor, often covered with a protective casing or plastic cover. It is impossible to determine the exact location without a visual inspection of the back wall, so prepare a flashlight and the necessary tools.
Localization of the compressor and access to the unit
The first step in the search is to determine the location itself compressor. In classic models of refrigerators with a bottom freezer, it is always located at the bottom of the back wall. If you have a model Hotpoint-Ariston or Beko with the No Frost system, access may be a little difficult due to the presence of an additional casing covering the technical components.
You will need to move the refrigerator away from the wall to provide free access to the back panel. Please note that in some modern models, such as Samsung or LG, access to the compressor can be achieved through a special removable panel at the bottom of the rear wall, which needs to be unscrewed. In old Soviet models, for example ZIL or Minsk, the compressor is often completely open.
Find a black metal cylinder - this is the motor-compressor. At its end (usually on the left or right side, depending on the model) you will see a plastic box or cylinder to which the electrical cable fits. It is inside this plastic case that the required starting relay is located start relay.
⚠️ Attention: Before removing any protective panels, make sure that the refrigerator is completely de-energized. Residual voltage in capacitors can be dangerous, and accidentally touching the bare contacts while the plug is plugged into a socket will result in electric shock.
Access to the relay may be limited by the design features of a particular manufacturer. For example, in refrigerators Electrolux often it is necessary to remove the fixing bracket holding the casing, while in Stinol it is enough to simply snap off the plastic clips. Carefully inspect the fasteners so as not to break the fragile plastic, which could become brittle over time.
Design and appearance of the starting relay
After you get to compressor, it is necessary to identify the element itself. The start relay is a small unit, usually black, white or gray, that fits directly onto the three contact pins coming out of the compressor housing. Visually, it resembles a box the size of a matchbox or slightly larger.
Inside this case hides a complex mechanism responsible for starting the engine. Depending on the type of refrigerator, there may be posistor (solid state relay) or an electromagnetic mechanism with a coil and a movable core. Posistor relays are more common in modern models Bosch i Siemens, while electromagnetic relays are typical for older units.
Wires from the thermostat and the general electrical circuit of the refrigerator are suitable for the relay. They are fixed in special terminals or soldered, depending on the design. If you see that the plastic case is melted, blackened or has traces of soot, this is a sure sign that the relay is burnt out and requires replacement.
Often the relay body has markings indicating the manufacturer and technical specifications. For example, the marking R600a indicates the type of refrigerant for which the device is optimized, and numbers like 100N or 33N indicate the power of the compatible compressor. This data is critical when selecting a new spare part.
What is the difference between a posistor and an electromagnetic relay?
A posistor relay works based on a change in the resistance of the thermistor when heated: in the cold state it conducts current, starting the starting winding, and when heated, it opens the circuit. An electromagnetic relay uses a coil: when starting, the current is high, the core retracts and closes the contacts of the starting winding, then the current drops and the spring opens the contacts. PTC resistors are more reliable because they do not have moving mechanical parts.
Typical signs of a relay failure
Understanding where the relay is located is useless without the ability to diagnose its failure. There are a number of symptoms that most likely indicate failure of this particular unit, and not the compressor or thermostat itself. Most often, users are faced with a situation where the refrigerator hums, but does not cool.
The most common symptom is the cyclic turning on and off of the motor. You hear a click, the compressor tries to start, hums for 3-5 seconds, then a second click is heard, and there is silence. After a few minutes the cycle repeats. This means that starting winding does not receive an impulse to start, or the opening mechanism is jammed.
Another sign is the complete refusal of the refrigerator to turn on when the backlight is working and the thermostat is working. If you turn the temperature control knob and you hear the thermostat click, but the compressor is silent, the problem may be an open circuit inside the relay. Also, a malfunction may be indicated by a specific burning smell emanating from the rear of the unit.
- 🔊 Frequent clicks: Rhythmic clicking every 2-5 minutes without starting the engine.
- 🔥 Overheating: The compressor becomes hot to the touch, although the refrigerator does not work.
- 🌑 No reaction: Complete silence when turned on, if the relay has completely broken the circuit.
- 💨 Smell: Perceptible smell of burnt plastic or wire insulation.
⚠️ Attention: If the compressor hums for more than 10-15 seconds and does not start, immediately unplug the refrigerator. Long-term operation in this mode (“humming on a jammed shaft”) can lead to burning of the windings of the engine itself, the repair of which is much more expensive than replacing the relay.
Sometimes the cause may not be the relay itself, but oxidized contacts or a loose fit on the compressor terminals. Vibration during operation of the refrigerator Haier or Atlant over time weakens the connection, which leads to sparking and heating. Therefore, before purchasing a new part, you should check the tightness of the contacts.
Instructions for removing and replacing the part
The process of replacing a relay requires care and adherence to the sequence of actions. Once you have determined the location of the unit and are convinced that replacement is necessary, you can begin dismantling. First, remove the retaining bracket or plastic casing that holds the relay to the compressor.
Next you need to disconnect the wires. In some models they are connected via connectors, in others they can be soldered (which is less common and requires a soldering iron). If the wires are tight, use pliers, but be careful not to damage the insulation. Remember or take a photo of which wire was connected where.
The relay itself is removed by gently rocking it from side to side. It simply slides onto the three pins of the compressor. If it has become stuck due to time and high temperature, do not use excessive force - it is better to carefully pry it off with a flat screwdriver, trying not to damage the compressor pins, since their failure will lead to depressurization of the system.
☑️ Algorithm for replacing the relay
Installation of the new element is carried out in the reverse order. Make sure that the new relay matches the markings of the old one (or the compressor parameters). It should fit onto the pins with a characteristic click and sit tightly. After connecting the wires, assemble the protective casing and only then turn on the refrigerator.
| Parameter | Old relay | New relay | Normal |
|---|---|---|---|
| Appearance body | Melted, there is soot | Intact, clean | No defects |
| Resistance (Ohm) | Infinity or 0 | Complies with the passport | Depends on the model |
| Fit tight | Sits freely | Tight | No play |
| Sound when shaking | Rumble (broken ceramic element) | Silence | No sound |
Diagnostics and testing with a multimeter
To be absolutely sure that the problem is in the relay and not in the compressor, it is recommended to carry out diagnostics using multimeter. This will avoid purchasing unnecessary spare parts. To check the relay, it must be completely removed from the compressor and disconnected from the wires.
First of all, check the integrity of the circuit. Switch the multimeter to continuity mode (or resistance measurement). If the relay is a posistor, measure the resistance between the contacts. In a cold state, it should be within 10-50 Ohms (the value depends on the specific model, for example, for Danfoss these are the same values, for PTC other manufacturers - different).
If the multimeter shows infinity (open) or zero (short circuit), the relay is faulty. You can also check the mechanical part: shake the relay near your ear. If something rattles or knocks inside, it means that the ceramic element or core is broken, and the part must be replaced.
It is also important to check the resistance of the windings of the compressor itself through the relay contacts. Ring the pairs of pins on the compressor. The resistance between the starting and operating windings should be the sum of the resistances of each winding relative to the common wire. If the resistance tends to zero or infinity, the problem may be in the engine itself.
Frequent errors during self-repair
When trying to find and replace DIY relays: Beginners often make mistakes that can aggravate the situation. One of the most common is ignoring labeling. Installing a relay with inappropriate parameters (for example, designed for a compressor of lower power) will lead to its rapid combustion and potential failure of the compressor.
Another mistake is careless handling of the wires. When removing an old “oak” relay from time to time, you can accidentally break the wire going to the terminal. Restoring the circuit in this case will require soldering and high-quality insulation, since the repair site will be in an area of high temperatures and vibration.
The cleanliness of the contacts is also often forgotten. Before installing a new relay, it is necessary to clean the contact pads on the compressor if they have oxidized. Oxides create additional resistance, cause heating and can cause repeated failure of even a new part.
- 🚫 Ignoring the type refrigerant: Relays for R134a and R600a may differ in design and response parameters.
- 🚫 Strong force: An attempt to force the relay into place may break the ceramic insert inside or damage the pins.
- 🚫 Lack of fixation: A forgotten spring clip will cause the relay to fly off from vibration at the first start.
⚠️ Attention: Technical characteristics of compressors and relays may vary even within the same brand. Always check the part codes on your refrigerator's identification plate with the parts catalogues. An incorrectly selected relay may not start the compressor or burn out after a few cycles.
Remember that if after replacing the relay the refrigerator started working, but after a short time it stopped cooling again, the problem may be deeper. Perhaps the compressor itself is faulty (turn-to-turn short circuit) or the thermostat is not sending the start signal correctly. In such cases, more in-depth professional diagnostics are required.
FAQ: Frequently Asked Questions
Is it possible to temporarily start a refrigerator without a relay?
Technically, you can start the compressor by applying voltage directly to the starting winding, but this is strictly not recommended. Without a relay, the compressor will not be able to start normally and will quickly burn out, since the starting winding will not be disconnected after the start. This will lead to expensive repairs or replacement of the entire unit.
How much does it cost to replace a relay at a service center?
The cost consists of the price of the spare part itself (usually from 500 to 2000 rubles, depending on the model) and the cost of the technician’s work. At the service center, the total amount can vary from 2500 to 5000 rubles and more, depending on the region and the difficulty of accessing the compressor.
Why does a new relay burn out immediately after installation?
There may be several reasons: incorrect selection of the relay model, a malfunction of the compressor itself (jamming, interturn short circuit), problems with thermostat (constant voltage supply) or power surges. It is necessary to carry out a complete diagnosis of the circuit.
Where to buy an original relay for a refrigerator?
It is best to look for original spare parts in specialized stores of spare parts for household appliances or from official dealers of the brand. When purchasing, pay attention to compatibility by part code or technical parameters (power, type of refrigerant), and not just by the brand name of the refrigerator.