If your refrigerator has stopped freezing, and the compressor is either silent or buzzing and clicking while trying to start, then with a high degree of probability the problem lies in the starting device. Refrigerator relay is a small but critical element that supplies a starting impulse to the motor winding. Without it, starting the compressor is impossible, and the entire cooling system turns into a useless box.
Many owners of household appliances are afraid to climb inside the mechanism, fearing electricity or a complex design. However, the process of replacing or checking this component does not require extensive engineering knowledge if done carefully and consistently. In this article we will look at how this unit works, how to correctly determine its type and how to safely replace it.
Before starting any work, it is necessary to completely de-energize the unit. Unplug the power cord from the outlet. This is a basic safety rule, violation of which can lead to serious consequences. Only after you have made sure that there is no voltage, you can begin to dismantle the rear panel and access the compressor.
Principle of operation and types of starting devices
To understand the connection process, it is important to know what exactly we are changing. Starting relay in the refrigerator it functions as a switch. When turned on, it supplies voltage to the starting winding of the compressor motor, helping it gain speed. As soon as the motor rotor reaches a certain rotation speed, the relay opens the starting winding circuit, and the compressor continues to operate on the main winding.
There are two main types of devices that can be called "relays" in common parlance. The first type is an induction (electromagnetic) relay. It works by current flowing through the main winding, which creates a magnetic field that draws in the core and closes the contacts of the starting winding. Such models often have a characteristic knocking sound during operation.
The second type is a posistor (thermal) relay. It uses a part called posistor, which changes its resistance when heated. In a cold state, the resistance is low, the current flows to the starting winding. The posistor heats up, the resistance increases sharply, and the circuit breaks. This type of device is considered more modern and quieter in operation.
- 🔹 Induction relays are more often found in older models of refrigerators and are distinguished by a characteristic click when starting.
- 🔹 PTC devices are more compact, do not have moving parts inside the housing and are considered more reliable.
- 🔹 The thermal protective relay is often combined with the starting one into a single unit, but it can also be a separate element that opens the circuit when overheated.
⚠️ Attention: Visually, relays from different manufacturers may look the same, but have different internal contact connections. Always check the markings on the body of the new and old device before installation.
An incorrectly selected relay can lead to burnout of the compressor windings. If you are not sure of compatibility, it is better to find the model using the catalog number indicated on the body of the burnt element. Using analogs “by eye” is a risk that may cost you the purchase of a new refrigerator.
Diagnostics of faults before replacement
Before running to the store for spare parts, you should make sure that the problem is in the relay, and not in the compressor or wiring. Malfunction symptoms They are often similar, but there are nuances. If the compressor hums for 2-3 seconds, then a click is heard and the hum stops - this is a classic sign that the starting device does not open the starting winding or does not send an impulse to it.
Carry out an external inspection. Remove the relay from the compressor (more on this in the next section) and shake it near your ear. If it rattles inside, like in a maracas, it means that the mechanical part is destroyed or the contacts have fallen off. Such a device can only be replaced, it cannot be repaired.
Also pay attention to the condition of the contacts. If they are blackened, melted or covered with carbon deposits, this indicates a spark has slipped and a poor connection. In posistor relays, you can check the resistance with a multimeter: in a cold state it should be low (about 30-50 Ohms), and when heated, it should go to infinity.
- 🔸 Humming without starting indicates a jammed compressor or a malfunction of the starting mechanism.
- 🔸 The lack of reaction of the refrigerator when plugged into the network may indicate open circuit in the thermal protective relay.
- 🔸 Frequent switching on and off of the motor (clocking) is often associated with incorrect operation of the thermostat or relay.
If after replacing the relay the situation has not changed, the problem may lie deeper. Perhaps an interturn short circuit in the motor windings or a compressor failure. In such cases, independent repair becomes economically unfeasible.
Instructions for dismantling the old relay
The removal process begins with access to the motor-compressor. It is usually located at the bottom rear of the refrigerator. You will need to remove the metal or plastic panel covering the unit. The mounting screws may be hidden under decorative plugs.
Locate the black “pot” of the compressor. A box fits on the side or top of it - this is our desired device. Dismantling usually does not require tools, except perhaps a flat-head screwdriver. The relay is simply put on three (less often four) pins coming out of the compressor.
☑️ Checklist before dismantling
Before tightening the relay, be sure to photograph or sketch which wire fits where. Insulation colors may differ in different refrigerator models Indesit, Atlant or LG. Standard contact marking: S (Start) - starting winding, R (Run) - working winding, L (Line) - phase from the network.
Carefully disconnect the wires. They can be fixed with terminals or simply pressed tightly onto the contacts. Do not pull on the wires themselves, hold on to the plastic ends. If the terminal is oxidized and cannot be removed, carefully clean it with fine sandpaper, but do not damage the metal.
⚠️ Attention: When removing the relay, do not make sudden jerks. The compressor pins are fragile and can break off inside the housing, which will require complex repairs involving pumping out freon.
After disconnecting the wires, remove the relay itself from the pins. It may fit tightly. Rock it from side to side, holding the compressor with your second hand so as not to damage the tubes.
Connection diagram and installation of a new device
Installation of a new element is carried out in the reverse order of dismantling. The main thing here is correct orientation. There is always a marking UP or an arrow pointing up on the relay body. This is critically important, since there may be a movable core or posistor inside that only works under the influence of gravity.
Push the relay onto the compressor pins until it stops. It should fit tightly and not wobble. Then connect the wires according to your diagram or photo. Typically, the phase wire (L) goes to the common contact, and the rest are distributed between the starting and working terminals.
Nuances of connecting wires
In some circuits, the wires may have color markings that differ from the standard. For example, the red wire can go to the starting winding, and the white wire to the working winding. Always rely on the diagram pasted on the compressor or in the technical documentation of the model.
Check the reliability of the connections. Tug lightly on each wire to ensure that the terminal does not come off due to vibration. Poor contact will lead to heating, sparking and repeated failure of the device. If the terminals are loose, you can carefully tighten them with pliers.
Here is a table to help you navigate the main contacts:
| Marking | Purpose | Wire color (typical) | Function |
|---|---|---|---|
| L (Line) | Line (Phase) | Red / Brown | Power supply |
| S (Start) | Start | Black / Green | Engine start |
| R (Run) | Work | White / Blue | Main work |
| C (Common) | Common | Yellow | Common point |
After connecting all the wires, replace the protective compressor housing, but do not screw it tightly yet. Plug in the refrigerator and listen. If you hear a confident start and a smooth hum, you have done it.
Checking operation and typical errors
The first start after replacement is the most exciting moment. Normal operation is characterized by a quiet, uniform hum of the compressor. After 10-15 minutes, the condenser tubes (usually the grille at the back or the sides) should start to heat up. This means that the refrigerant has flowed through the system.
One of the common mistakes is installing a relay of inappropriate power. If the relay is designed for a compressor of lower power, it will quickly overheat and turn off the motor. If it is larger, the contacts may not open in time, which will lead to an overload of the starting winding.
Ignoring the state of the thermal relay is also considered an error. Often the starting and thermal relays are replaced in pairs, even if the thermal relay is still “ringing”. The old thermal relay may have changed response characteristics and will soon turn off the new compressor or new starter.
- 🔺 Error: Installing the relay upside down (poor orientation).
- 🔺 Error: Poor contact in the terminals (sparking and heating).
- 🔺 Error: Attempting to repair a burnt posistor (useless, only replacement).
⚠️ Attention: If after replacing the relay the compressor stalls again after a few seconds, immediately turn off the refrigerator. Repeated starting attempts can completely kill the engine. Check the voltage in the network - it should be within 220V ±10%.
Care and extending the service life of the compressor
In order for the new relay and the compressor itself to serve for a long time, it is important to ensure the correct operating conditions. Ventilation is a key factor. The back wall of the refrigerator should be at least 5-10 cm from the wall. If the heat is not removed, the compressor will overheat and the thermal relay will constantly turn it off.
Regularly, at least once a year, wipe the rear grille from dust. The dust layer acts as a heat insulator, interfering with cooling. Also check the door seals: if they allow heat to pass through, the compressor will work without stopping, which reduces the life of all its parts, including the relay.
Do not overload the refrigerator products. While this does not directly affect the relay, it does cause the compressor to run longer, increasing the number of on/off cycles. Each switch-on is a load on the contacts of the starting device.
Monitor the stability of the voltage in your electrical network. Power surges are the enemy of any electronics and motors. If the light in your house often “flashes”, think about installing a voltage stabilizer for the refrigerator.
Is it possible to install a relay from another manufacturer?
Yes, this is often possible if the electrical characteristics (current, voltage, type of compressor) and mounting dimensions match. However, it is better to look for an original or a proven analogue, since the location of the contacts may differ.
Why does the relay burn out repeatedly (constantly)?
If a new relay burns out soon after installation, the reasons may be: a malfunction of the compressor itself (turn short circuit), voltage surges in the network or incorrect selection of relay power.
How much does it cost to replace a relay in a service?
The cost consists of the price of the spare part (usually 500-1500 rubles) and the work of the technician. At the service center, the final amount can be 2-3 times higher than the cost of self-repair.