Sudden stoppage of operation compressor or its characteristic hum without starting often indicates a failure of the start relay. This small part plays the role of a starter for the engine, providing the necessary torque in the first seconds of switching on. Searching for a relay This is the first step in diagnostics, which can save you a significant amount on calling a technician if you decide to replace it yourself.
The location of this element is almost always tied to the compressor, but access to it can be limited organized differently depending on the make and model of your refrigeration unit. In some cases, for a visual inspection it is enough to simply look behind the back wall, in others you will need to dismantle the protective casing. Understanding where exactly the relay is locatedis critical for correct diagnosis and safe work.
In this article we will analyze in detail the algorithm for detecting, checking and replacing the start relay in refrigerators of various brands. You will learn how to distinguish a relay malfunction from a breakdown of the compressor itself, what tools are needed and what nuances you should pay special attention to. Safety When working with electrical appliances, these are not just words, but a mandatory condition, ignoring which can lead to electric shock.
Design and purpose of the starter relay
The starting relay is an electromechanical device, the main task of which is to briefly connect the starting winding of the compressor. When the refrigerator is turned on, the motor rotor is at rest, and spinning it requires significantly more force than maintaining rotation. It is the relay that supplies current to the starting winding, creating the necessary phase shift and magnetic field.
There are several types of these devices, the most common are electromagnetic and posistor (thermal) options. Electromagnetic relays they work due to the current passing through the main winding: when starting, the current is high, the coil draws in the core and closes starting circuit contacts. As soon as the engine picks up speed, the current drops, and the core, under the influence of gravity or a spring, opens the circuit.
In modern models, they are more often found posistor relays, which do not have moving mechanical parts. Inside them there is a thermistor (posistor), which, when voltage is applied, sharply increases its resistance, actually breaking the starting winding circuit. After cooling (which takes a few minutes), it is ready for use again. That is why, after turning off the refrigerator, you cannot turn it on immediately - you need to wait until the posistor cools down.
⚠️ Attention: An attempt to start a compressor with a faulty or “stuck” relay can lead to burnout of the motor windings. If you hear clicks, but the compressor does not start, immediately unplug the device.
Understanding the principle of operation helps in diagnosis: if the relay is electromagnetic, it can sometimes be “revived” by lightly tapping it (although this is a temporary measure), while a burnt posistor requires only replacement. Visually, they also differ: electromagnetic ones often have a more complex shape with a visible coil, and posistor ones look like compact black plastic boxes.
Localization of the relay depending on the refrigerator model
The answer to the question where to find the relay, in 95% of cases lies in the plane of the rear wall of the refrigerator, directly at compressor. The compressor is usually a black metal “tank” located in the lower recess. The relay is placed directly on the terminals (contacts) of the compressor. However, the path to it may be difficult due to the design features of the case.
In classic models of brands Atlant, Indesit, Beko i Stinol access is as simplified as possible. It is enough to move the refrigerator away from the wall, remove the back metal cover (if there is one), or simply tilt the unit to see the compressor. In such cases, the relay is attached to three contacts and secured with a metal bracket or plastic latches.
With refrigerators Liebherr, Bosch i Siemens the situation may be more complicated. Often the compressor group is closed with an additional plastic or metal casing, which is secured with screws or powerful latches. In some models LG and Samsung with the No Frost system, the relay may be hidden behind the bottom decorative panel, which needs to be carefully pryed off with a screwdriver.
If If you don't see the relay right away, look at the sides of the compressor. In dual-compressor models there will be two of them, and the relays will be located on each unit. It is important not to confuse the starting relay with a thermal relay (protective), although in modern assemblies they are often combined into one unit. Thermal relay is responsible for protection against overheating and usually has the form of a tablet or plate pressed to the compressor body.
Algorithm for searching and accessing details
To begin work, you must completely turn off the power to the refrigerator. Unplug the cord from the socket - this is an axiom, the neglect of which is deadly. After this, move the unit away from the wall, giving yourself free access to the rear. If the floor is slippery, place a rag or cardboard under the feet to avoid damaging the coating when moving.
The next step is to dismantle the protective panels. If the compressor is covered with a metal sheet, unscrew the mounting screws around the perimeter. If the casing is plastic, inspect it for latches. Proceed with caution: old plastic can be brittle. Your goal is to gain direct visual and tactile access to the “hump” of the compressor, where the contacts are located.
☑️ Access to the relay
Find a box placed on the three pins coming out of the compressor. This is the required relay. It can be secured with a metal U-shaped bracket, which must be carefully pressed, or simply held in place by a tight fit. In some models, for example, old ZIL or Minsk, the relay can be mounted on a separate frame next to the compressor, connected by wires, but this is rare for modern technology.
⚠️ Attention: Before removing the relay, take a photograph of the position of the wires and contacts. The color marking of the wires may not correspond to the standard, and mixing up phase and zero during assembly can damage the new part.
If the relay is hidden deep in a niche and is poorly lit, use a flashlight. Make sure there are no traces of oil or moisture around, which could indicate other system malfunctions. Dry and clean in the compressor area - a sign of a healthy refrigerant system.
Location table in popular brands
To make your search easier, a summary table is provided below, demonstrating the features of the location of relays in refrigerators from various manufacturers. Although the general principle is the same, access nuances can significantly affect repair time.
| Brand | Relay location | Mounting type | Access features |
|---|---|---|---|
| Atlant | On contacts compressor | Metal bracket | Open access, often without casing |
| Indesit | On the compressor contacts | Plastic latches | Requires removal of the rear covers |
| Liebherr | In the compressor niche | Screw connection | Difficult access, panels need to be dismantled |
| Samsung | Side or rear of the compressor | Latches + bracket | Often covered with a decorative panel |
| Bosch | On the compressor terminals | Tight fit | Removal of the bottom box is required |
This table is for reference character. Depending on the year of manufacture and the specific model series, the design may differ. Always rely on visual inspection. Universal Standard there is no fastening, so care is your main tool.
If you find that the relay is filled with oil or has traces of burning, this is a sure sign of a malfunction. In such cases, replacement is required immediately. Sometimes, along with the relay, the protective thermal relay is also changed, since they work in pairs and wear out at the same time.
Diagnostics and signs of malfunction
Before looking for a new relay, you should make sure that this is the problem. There are several characteristic signs indicating failure of the starting device. The most obvious one is that the compressor hums for 3-5 seconds, then a click is heard and it goes silent. After some time, the cycle repeats. This means that the starting winding is not connected or disconnected in time.
The second sign is the lack of starting when the unit is completely silent. If you don't even hear a hum, the contacts inside the relay may have oxidized or burned out completely. A visual inspection can confirm the diagnosis: if soot, melted plastic, or a burning smell is visible inside the plastic case, the part is definitely faulty..
How to check a relay with a multimeter?
To check a posistor relay, you need to ring its contacts. The resistance should be within normal limits (usually several tens of ohms). If the multimeter shows infinity or zero, the relay is broken or broken. Electromagnetic relays are checked for core mobility and coil integrity.
It is also worth paying attention to the temperature of the relay. If, after trying to turn it on, it becomes hot within a couple of seconds, then current is flowing through it, but it does not start. This can be either a breakdown of the relay itself or a sign of a “jamming” compressor. Compressor diagnostics - a more complex process that requires checking the resistance of the windings.
If you find that the contacts on the compressor itself are oxidized or burnt, they must be cleaned before installing a new part. Use fine sandpaper or a file, act carefully so as not to damage the terminals. Good contact is the key to long-term operation of the new spare part.
Replacement process and performance check
Replacing a relay is a procedure accessible even a beginner, if you act consistently. After you have removed the old part, go to the store or order an analogue on the Internet. It is important to buy a relay with identical resistance of the posistor and connection diagram. There are few universal solutions; it is better to search by the catalog number indicated on the case.
Installation is carried out in the reverse order of removal. Push the new relay onto the compressor contacts as far as it will go. Make sure it fits snugly and doesn't wobble. If a retaining bracket was used, replace it in place. Connect the wires (if they were disconnected), observing the polarity, if it was marked.
After assembling all the panels and returning the refrigerator to its place, turn it on. In the first seconds, listen to the operation of the compressor. It should start smoothly, without buzzing or clicking. After 10-15 minutes, check whether the condenser (grid at the back) has started to heat up - this is a sign that the refrigerant has circulated and the system is working.
⚠️ Attention: If after replacing the relay the compressor hums again and does not start, do not try to turn it on repeatedly. The problem may be in the compressor itself (an interturn short circuit or a mechanical wedge), and further attempts to start will completely kill the motor.
Successful replacement of the relay not only returns cold to the chamber, but also extends the life of the compressor, eliminating the need for it to work in the “start-stop” mode. Regularly check the cleanliness of the condenser at the back of the refrigerator to avoid overheating and repeated breakdowns.
Frequently asked questions (FAQ)
Is it possible to replace the relay with a universal one if the original cannot be found?
Yes, there are universal starting relays that are suitable for most compressors of a certain power. However, it is important to select a device with a suitable power range (for example, 1/8 to 1/2 hp). Installing a relay that is too powerful or weak can lead to incorrect operation.
Why does a new relay burn out a week after replacement?
This may indicate problems with the compressor itself (for example, increased starting current due to wear) or voltage surges in the network. The cause may also be incorrect installation (wrong side) or defective part itself. It is recommended to check the voltage in the network and the condition of the motor windings.
How much does it cost to replace a relay at a service center?
The cost consists of the price of the spare part and the work of the technician. On average, the service costs from 1,500 to 3,000 rubles, depending on the region and the complexity of access to the compressor. Do-it-yourself purchase and replacement can save up to 70% of this amount.
Do you need to release freon to replace the relay?
No, the start relay is located on the electrical part of the compressor and is not connected to the sealed circuit where the refrigerant circulates. Replacing the relay does not require violating the integrity of the cooling system and does not require refilling with freon.