Sudden stoppage of the compressor or its characteristic A click followed by silence often indicates a failure of the start-up relay. This small part is a key element in the motor's electrical circuit, responsible for starting the rotor and protecting the windings from overheating. If you are faced with the fact that refrigerator has stopped freezing, and the engine either does not start, or hums for a couple of seconds and goes silent, there is a high probability that it is time to replace this component.
Independent installation of a relay in a refrigerator is a completely solvable task for a person with basic skills in working with tools and compliance with safety regulations. However, before starting any work, it is necessary to completely de-energize the unit. This is a critical condition and, if ignored, may result in electric shock or damage to the control electronics. In this article we will look in detail at how to correctly diagnose a breakdown, select a compatible part and install it in its original place.
The replacement process does not require complex specialized equipment, but requires attention to detail and sequence of actions. An incorrectly selected or installed device can cause failure of the device itself, which will turn minor repairs into an expensive replacement of the motor. Therefore, it is important to clearly understand the operating principle of the starting system and strictly follow the instructions of the manufacturer of your model of refrigeration equipment. compressor, which will turn minor repairs into expensive engine replacements. Therefore, it is important to clearly understand the operating principle of the starting system and strictly follow the instructions of the manufacturer of your refrigeration equipment model.
Diagnosis of a malfunction of the starting relay
Before disassembling the equipment, you need to make sure that the problem lies in the relay. The primary sign of a malfunction is a characteristic sound: a series of clicks at intervals of several seconds, after which the refrigerator becomes silent again. If the motor housing remains cold and the light inside is on, then the power circuit is most likely intact, but starting of the engine is blocked by protection.
For accurate diagnosis, you should get to the compressor, which is usually located in the lower rear part of the unit. When you remove the protective cover, you will see a black cylindrical or box-shaped element that fits onto the motor rod. It is in this node that the starting and thermal relay is located. A visual inspection may reveal traces of burning, melting of plastic or corrosion of contacts, which will immediately indicate the need for replacement.
⚠️ Attention: If, after disconnecting the refrigerator from the network, you hear a ringing inside the relay when you shake it, this is a sure sign that the internal contact group is damaged. In this case, the part must only be recycled and replaced with a new one.
Checking the integrity of the compressor windings is also important, since a faulty relay could burn out due to a short circuit in the engine. Using a multimeter, you need to ring the motor leads. If the resistance between the contacts shows infinity or, conversely, zero, the problem may be deeper than simply replacing the relay. In this case, installing a new part will not restore the operation of the refrigerator compartment. problem refrigeration chamber.
Preparation of tools and selection of a new relay
To successfully carry out the work, you will need a minimum set of tools. First of all, you need pliers or pliers to remove the fixing brackets, as well as a screwdriver (often a Phillips or flathead, depending on the casing model). It would be a good idea to have a multimeter on hand for the final check of the contacts and a wire cutter if you need to strip the wires.
The most important step is selecting the right one starting relay. These devices are not universal: they differ in the type of compressor (inverter or conventional), motor power, contact location and installation angle. Installing an unsuitable part may result in the motor not starting or the winding burning out.
In order not to make a mistake with the choice, it is best to remove the old relay and look for an analogue by the markings on the body. If the marking is erased, you need to look for the compressor model, which is stamped on the metal housing of the motor. Manufacturers often use standard series, such as RT, R-1, R-2, R-3, R-4, R-5, R-6, R-8, RTK-1, RTK-1-3, RTK-1-3, RTP-1, RTP-2, RTP-3, LS-35B, LS-40B, LS-45B, LS-50B, LS-55B, LS-60B, LS-75B, LS-80B, LS-90B, LS-100B, MCR, SCR, T, K, N, S, H, L, Z, G, R, B, C, D, E, F, J, P, Q, U, V, W, X, Y.
☑️ Preparation for replacement relay
The table below shows the main types of relays and their compatibility with various series of compressors, which will help you navigate when purchasing:
| Relay type | Design features | Compatible compressors | Installation angle |
|---|---|---|---|
| RTK (RTK-1, RTK-1-3) | Thermal protection in a separate housing | Donbass, Saratov, ZIL | Horizontal/Vertical |
| RTP (RTP-1, RTP-2, RTP-3) | Compact, with thermal protection | Donbass, Minsk, Atlant | Strict vertical |
| LS (LS-35B, LS-40B) | Plastic case, universal | LG, Samsung, Indesit | Any position |
| SCR (series) | For powerful motors | Electrolux, Bosch, Siemens | Vertical |
Removing the old one devices
The process of removing the old relay begins with completely disconnecting the refrigerator from the power supply. You will then need to remove the rear metal panel at the bottom of the unit to gain access to the compressor. If the panel is attached with screws, they must be unscrewed; if it is held on by latches, carefully press them out.
A black plastic or metal casing is placed on the compressor rod, which is fixed with a spring bracket or screws. Carefully remove the retainer using pliers or a screwdriver. Once you remove the cover, you will see the wires going to the relay. Before disconnecting them, it is strongly recommended take a photo of the connection diagramto avoid mixing up the contacts when installing a new part.
The relay itself sits tightly on the contacts of the compressor. It needs to be gently rocked from side to side, while pulling it up. Do not use excessive force to avoid damaging the copper leads of the motor. If the relay is stuck, you can slightly warm it up with a hairdryer, but be careful with the plastic elements.
What to do if the wires are broken?
If during dismantling the wires are torn from the relay itself, do not panic. Strip the ends of the wires, twist them and solder them, being sure to insulate the connection with heat shrink or high-quality electrical tape. The main thing is to prevent a short circuit.
After removing the part, inspect the inside of the casing. There may be a thermal protection (tablet), which could also fail. In some models it is built into the relay, in others it is a separate element. Check its integrity with a multimeter: in a cold state it should ring.
Installing a new relay: step-by-step instructions
Installing a new starting relay is done in the reverse order of dismantling. First of all, make sure that the new device has the same markings or is a direct analogue in terms of characteristics. Pay attention to the inscription UP or the arrow on the housing - they point to the top part, which should face up when installed on a running compressor.
Insert the leads of the new relay onto the contact pins of the compressor. They should fit tightly and with light force. If the relay contacts have a different configuration, you may need an adapter, which is sometimes included in the kit, but it is better to avoid such situations and look for an exact copy. Securely secure the relay in a metal or plastic holder frame.
⚠️ Attention: It is strictly forbidden to install the relay if there are oxides or dirt on the compressor contacts. Clean the contacts with fine sandpaper or alcohol before installation, otherwise the contact resistance will lead to heating and repeated failure.
Connect the wires according to the previously taken photograph or diagram. Typically the black wire goes to one pin and the white or red to the other, but colors can vary depending on the manufacturer. Make sure that the wires are not pinched by the housing and do not touch the hot parts of the compressor.
The final step is to install the protective casing and return the fixing bracket. The casing should fit tightly, without gaps, protecting the contacts from moisture and dust. Only after all the mechanical parts are installed can you connect the refrigerator to the network.
Checking the system's performance
After connecting the refrigerator to the network, listen carefully to the sounds coming from the compressor. In the first seconds, you should hear the smooth hum of a starting engine. If you hear a hum, which after 2-3 seconds is replaced by a click and silence, it means that the startup did not occur. This may indicate incorrect installation, a defective new relay, or a malfunction of the compressor itself.
Check the heating of the relay housing during operation. After 10-15 minutes of operation, it may be warm, but not hot. If the relay heats up to the point where it is impossible to touch it, it means that the current passing through it is higher than normal, which can lead to melting of the contacts. In this case, you need to immediately turn off the device.
It is also worth checking the operating cycle. Normal mode assumes that the compressor runs for a certain time (for example, 10-15 minutes), and then turns off for the same period. If the refrigerator runs non-stop or turns on too often, the problem may be not only in the relay, but also in the thermostat or freon leak.
Frequent errors during replacement and safety measures
One of the most common mistakes is ignoring the installation angle. Many types of relays, especially those with a posistor, are sensitive to position in space. If you install such a relay sideways or upside down, the posistor may not perform its function and the engine will not start. Always follow the marking UP.
Another mistake is using a relay with an inappropriate power range. If you put a relay designed for a low-power motor on a powerful compressor, its contacts will quickly burn out. Conversely, a relay for a powerful motor on a weak one may not open the circuit in time, which will lead to overheating of the windings.
- 🔌 Connection error: Installed phase and neutral wires may prevent the engine from starting or lead to a short circuit.
- 🧊 Ignoring moisture: Installing the relay in a wet position casing or operation in conditions of high humidity without contact protection.
- 🔧 Mechanical damage: Broken plastic fasteners during careless dismantling, which leads to vibration and poor contact.
Also It is important to remember safety precautions when working with electricity. Even after disconnecting from the network, a charge may remain in the capacitors. Do not touch exposed wires with your hands; use a tool with insulated handles. If you are not confident in your abilities, it is better to entrust the repair to professionals.
⚠️ Attention: If, after replacing the relay, the compressor makes a strong metallic knock or the vibration of the refrigerator has increased sharply, turn it off immediately. This may mean that the problem is in the mechanical part of the motor (valves, piston group), and further work will lead to its complete destruction.
Questions and answers (FAQ)
Is it possible to repair an old relay rather than change it it?
Theoretically, some types of relays (for example, RTK) can be disassembled and cleaned the contacts. However, modern relays often have a sealed housing or contain posistors that cannot be restored. Considering the low cost of a new part and the risks of repeated failure, repairing an old relay is considered economically infeasible and less reliable.
Why did the new relay burn out immediately after installation?
There may be several reasons: a malfunction of the compressor itself (interturn short circuit, jamming), power surges in the network, incorrect installation (not fully seated) contacts) or defective new part. It is also possible that a relay with unsuitable current characteristics was selected.
How to distinguish a starting relay from a thermal one?
A starting relay usually has a more massive body and is connected in parallel to the starting winding. The thermal relay (protection) is often a bimetallic strip in a separate casing or built into the overall structure, but connected in series with the working winding. In modern compact models, they are often combined into one block.
Where can you find the relay markings if they are erased?
If the markings on the relay itself are not readable, look for information on the compressor housing (the black “barrel” at the back of the refrigerator). The type of motor will be indicated there (for example, NL11FT or FR6CA). Using this compressor model, it is easy to find the catalog number of a suitable relay on the Internet.
Is it safe to leave the refrigerator turned on without a metal relay casing?
A short-term check of operation without a casing is acceptable, but it is impossible to operate the refrigerator in this form all the time. The casing protects against dust, moisture and prevents accidental contact with live parts. In addition, it acts as a screen against electromagnetic interference.