Sudden the refrigerator stopping and the silence that reigns in the kitchen are often the first signals of a serious breakdown compressor. In most cases, the unit hums for a few seconds, clicks and goes silent without starting the cooling process. This is a classic symptom of a failure of the starting protection device, which is responsible for starting the engine. Understanding how to remove the start relay from the refrigerator compressor is the first and most important step for diagnosis and subsequent repair.
Replacing or checking this element yourself can bring the refrigerator back to life, saving significant money on calling a technician. However, the risks associated with electrical current and refrigerant must be clearly understood before starting work. In this article, we will analyze in detail the design of the unit, the types of relays and the algorithm for safely dismantling the element for further inspection or replacement.
Before you begin disassembling, make sure that you have basic skills in working with tools and follow safety precautions. Careless handling of compressor parts can lead to the final failure of an expensive unit. Let's look at what exactly this mechanism is and why it is so important to the operation of your refrigeration equipment refrigeration technology.
Design and purpose of the starting relay
The starting relay is a small but critical electrical component that is attached directly to the compressor housing. Its main task is to briefly apply voltage to the starting winding of the motor, which allows the rotor to move and begin to rotate. As soon as the engine reaches the required speed, the relay opens the starting winding circuit, and the compressor continues to operate on the main winding.
There are two main types of such devices that are found in household refrigerators: induction (electromagnetic) and posistor. Induction relays operate on the principle of a magnetic field created by current in a coil and are often equipped with a movable core. PTC models, more modern and widespread in technology Indesit, LG and Samsung, use a thermistor that changes its resistance when heated, opening the circuit.
Thermal protection is also often built inside the case, which turns off the compressor when overheated or overcurrent. It is this protection mechanism that often produces a characteristic clicking sound when the device tries to start but encounters resistance or a malfunction. Understanding the difference between relay types helps to quickly diagnose the problem.
- 🔹 Induction relays are more often found in older models of Soviet-made refrigerators and have a more complex mechanical design.
- 🔹 PTC relays are considered more reliable, have no moving parts inside and are less susceptible to contact sticking.
- 🔹 Thermal protection in both cases serves as a fuse that prevents the compressor windings from burning out when jammed.
⚠️ Attention: Charge residues may remain inside the start relay or sparking may occur. Before touching the contacts, make sure that the refrigerator is completely disconnected from the power supply for at least 15 minutes.
Necessary tools and preparation for work
In order to remove the start relay efficiently and safely, you do not need complex professional equipment. However, having the right tool will greatly simplify the task and minimize the risk of damaging wires or plastic elements. The main requirement is to ensure clear access to the rear of the refrigeration unit.
You will need a flathead and Phillips screwdriver to remove the protective covers, if present. It would also be useful to have a multimeter for subsequent testing of the contacts, although the dismantling process itself can be carried out without it. It is important to prepare a clean rag, since dust and technical grease often accumulate in the compressor niche.
☑️ Preparation for dismantling the relay
Before starting work, be sure to move the refrigerator away from the wall to ensure all-round access to the compressor. Make sure there is no tension in the power cord and that you have enough room to maneuver. If the compressor has a metal cover covering the contact group, it must be carefully removed.
Step-by-step instructions: how to remove the relay
The dismantling process begins with a visual inspection of the rear panel of the refrigerator. At the bottom of the housing, usually on the right or left side, there is a compressor - a black metal tank. A plastic box is placed on its protruding terminals, which is our desired starting relay. In some models, for example Beko or Atlant, it can be additionally secured with a metal bracket.
First of all, you need to remove the fixing bracket, if any. It is usually pryed off with a flat screwdriver or simply snapped off with your fingers if it is made of plastic. After this, grab the relay body and gently pull it down, while slightly rocking it from side to side. You should not make sudden jerks, as the contacts may be slightly stuck or oxidized.
When the relay begins to be removed, you will see three contact pins coming out of the compressor. The relay is simply pressed onto them. Carefully pull off the plastic housing, releasing the terminals. At this stage, it is important not to damage the wires going to the relay, as they can be short and fragile over time.
After removing the relay, carefully inspect the inside. There should be no traces of burning, melted plastic or black soot. The presence of such signs indicates that the device has burned out and requires replacement. Also check the condition of the contacts on the compressor itself - they should be clean and even.
⚠️ Attention: It is strictly forbidden to remove the relay by pulling the wires. This will lead to broken wires or damage to the insulation, which will require complex soldering and restoration of the circuit.
Diagnostics and serviceability check
After you have managed to remove the start relay from the refrigerator compressor, the diagnostic stage begins. The simplest way to check for posistor relays is visual inspection and testing with a multimeter. In a cold state, the resistance between the contacts should be within normal limits (usually several tens of Ohms), and when heated, the posistor should go into a gap.
For electromagnetic relays, it is important to check the mobility of the core. It should move freely inside the reel and not be stuck in the down or up position. If the core is stuck, the contacts will not open and the starting winding will burn out. The integrity of the coil is also checked for breakage.
The thermal relay, built into the structure or running separately, is checked for current flow. When cold, the chain should ring short. If the multimeter shows infinite resistance, it means that the thermal protection has tripped irreversibly or has burned out, and the device requires replacement.
| Type of fault | External sign | Multimeter readings | Solution |
|---|---|---|---|
| Burnt posistor | Black plaque, cracks | Break or short circuit | Replacing the relay |
| Sticking contacts | The compressor is humming constantly | Short circuit in the off state | Relay relay |
| Thermal protection malfunction | The refrigerator does not turn on | Open circuit | Replacement protection |
| Oxidation of contacts | Unstable operation | Resistance is higher than normal | Cleaning or replacement |
Features of replacement and selection of analogues
If the diagnostics show a malfunction, the relay must be replaced. The main rule when selecting a new element is compliance with the markings. The model code or list of compatible compressors is always marked on the device body. Ignoring this data may lead to the fact that the new component will not fit in terms of operating current or mounting geometry.
When installing a new relay, make sure that it fits tightly on the compressor terminals and without distortions. Orientation is important: usually the "UP" marking or arrow must face up for the mechanism to operate correctly under gravity (for induction models). For posistor ones, this is less critical, but it is better to respect the factory position.
In some cases, especially in old refrigerators Zil or Minsk, you can find relays that are no longer produced. In such situations, the installation of universal analogues is allowed, but careful verification of the current characteristics is required. The compressor power must fall within the range indicated on the new relay.
Is it possible to repair the old relay?
Theoretically, the induction relay can be disassembled and the contacts cleaned fine sandpaper and put it back together. However, this is a temporary measure. The posistor relays cannot be repaired, since the posistor tablet is a disposable element.
After installation, reassemble all protective covers in the reverse order. Plug in the refrigerator and listen to it work. Startup should be smooth, without prolonged buzzing or repeated clicks. If the compressor started working and after some time began to cool, the repair can be considered successful.
Frequent errors during dismantling and installation
One of the most common mistakes is trying to remove the relay without disconnecting the refrigerator from the network. This is not only life-threatening, but can also lead to a short circuit if you accidentally short the contacts with a screwdriver during dismantling. Always remove the plug from the outlet before starting any work.
Another mistake is ignoring the condition of the wires. Often the insulation on the wires connecting to the relay dries out and cracks due to time and the high temperature of the compressor. If you remove the relay carelessly, these wires can be damaged, which will require their extension and insulation.
Also, beginners often confuse the connection side. The relay fits onto the compressor in only one correct position. If you try to put it on upside down, it will either not fit into place, or the contacts will not match the compressor terminals. Do not use excessive force if the relay does not move by hand.
⚠️ Attention: Technical characteristics of compressors and types of relays may vary depending on the year of manufacture and model of the refrigerator. Always check the markings on the body of the part with the manufacturer's documentation or catalogs before purchasing a replacement.
Questions and answers (FAQ)
Is it possible to start a refrigerator without a starting relay?
Theoretically, you can start an asynchronous refrigerator motor by applying voltage to the starting winding manually through button or circuit, but this is extremely dangerous and requires qualifications. In domestic conditions, starting without a relay is impossible, since the engine will only hum, and the starting winding will quickly burn out from overheating. The relay is a mandatory element of the circuit.
Why does the new relay burn out immediately after installation?
If the new starting relay burns out instantly, this most often indicates a malfunction of the compressor itself. An interturn short circuit in the motor windings or a mechanical wedge of the piston group is possible. In such cases, the compressor draws too much current, which melts the relay contacts. Motor diagnostics are required.
How to distinguish a posistor relay from an induction one?
A posistor relay is usually lighter, there is no moving core inside that would rattle when shaking. The induction relay is heavier, the knocking of the metal rod is heard inside. In addition, posistor often have a more compact rectangular or square body, while induction can be cylindrical or have a more complex shape.
Do I need to wait after removing the relay before turning it on again?
Yes, definitely. The posistor (thermistor) requires cooling time, usually 3 to 5 minutes, to restore its resistance. If you turn on the refrigerator immediately after turning it off, the posistor will be hot and will not perform its function of opening the circuit, which can lead to the humming of the compressor without starting.