A sudden stop of the compressor or its chaotic attempts to start with a characteristic click are classic signs of a faulty starting mechanism. Owners of refrigerators Vestel often face a situation when the unit stops freezing, and the motor itself hums for only a few seconds, after which a loud click is heard and silence ensues. In most cases, the cause of this behavior is a failed start-protection relay, which is responsible for supplying voltage to the motor windings.
Before calling a technician or buying new equipment, it is worth conducting independent diagnostics, since replacing this part is often inexpensive and does not require complex professional equipment. Start relay This is an electromechanical switch that supplies an impulse to the starting winding of the compressor, helping it gain the required speed. If this element burns out or its contacts stick, the engine cannot start, which leads to overheating and thermal protection.
In this article we will look in detail at how to determine the fault in the relay, what tools are needed to check and whether it is possible to restore the operation of the refrigerator Vestel with your own hands. You'll learn how to safely remove a part, what to look for during a visual inspection, and how to properly use a multimeter to measure resistance. Competent diagnostics will save time and money, bringing the equipment back to life without extra costs.
The principle of operation and types of relays in Vestel refrigerators
In order to carry out quality repairs, you need to understand the structure of the unit you are working with. Refrigerators of the Turkish brand Vestel, as in most modern models, predominantly use posistor (PTC) relays. Inside the plastic case there is a special ceramic element - a posistor, the resistance of which increases sharply when heated. When the refrigerator is turned on, a current passes through this element, it heats up and opens the circuit of the starting winding, leaving only the main winding working.
However, in older models or specific series, induction-dynamic relays with a moving core may be found. In such devices, the current passing through the coil creates a magnetic field that draws in the core and closes the starter contacts. After the motor starts, the current drops, the spring returns the core to its original position, and the circuit opens. Understanding the type of relay you have is critical, as the methods for testing them may vary slightly.
What is the difference between a posistor and an electromagnetic relay?
PTC relays are considered more reliable and durable because they have no moving parts that are subject to mechanical wear. Electromagnetic relays have a movable core, which over time can stick or lose spring elasticity, which leads to frequent breakdowns. Visually, a posistor looks like a tablet with holes, and an electromagnetic relay contains a coil and a movable rod.
Relay malfunction is often accompanied by specific symptoms that cannot be ignored. The compressor may try to start, making a humming sound, but without the characteristic start-up click. Or, conversely, clicks will be heard regularly at regular intervals until the thermal protection switches off the unit completely. In some cases, a rattling sound can be heard inside the relay housing, which indicates mechanical destruction of the internal components.
Visual diagnostics and external signs of failure
The first stage of any diagnosis should always be a thorough external examination. Before picking up measuring instruments, it is necessary to remove the relay from the compressor housing. To do this, the refrigerator must be disconnected from the power supply by unplugging the cord from the outlet. Remove the rear protective panel, locate the compressor at the bottom of the unit and carefully disconnect the plastic box into which the contacts are inserted.
Carefully inspect the relay housing for melting, cracks or burn marks. If the plastic is blackened or deformed, this is a sure sign that overheating has occurred inside due to a short circuit or poor contact. It is also worth sniffing the part: the smell of burnt insulation or scorched plastic clearly indicates the need for replacement. Sometimes you can notice oxidation or charring of the metal contacts through which current is transmitted.
⚠️ Attention: If traces of soot or severe melting are visible on the relay body, also check the condition of the compressor windings. A short circuit in the relay could be a consequence rather than the cause of the problem, and the new element will burn out immediately after switching on.
After a visual inspection of the case, it is necessary to check the insides. Carefully open the plastic casing (if the design allows) or simply inspect the holes through which the posistor is visible. The ceramic element must be intact, without chips or cracks. If pieces of ceramic are dangling inside or a black coating is visible on the contacts, the part is faulty. In induction relays, check whether the movable core moves freely and does not jam.
Instrumental check with a multimeter
The most accurate diagnostic method is to check the electrical parameters with a multimeter. This device will allow you to determine the integrity of the circuit and the resistance of the posistor, which cannot be done by eye. Before starting measurements, make sure that the relay has completely cooled down, since posistors retain residual resistance after heating, which can distort the test results.
To carry out the test, set the multimeter to resistance measurement mode (Ohm). First, ring the circuit between the contacts responsible for the main winding. When cold, the posistor should have a low resistance, usually in the range of 3 to 50 ohms, depending on the model. If the device shows infinity (one on the screen) or, conversely, zero, this indicates a breakdown or open circuit.
Next, you need to check the contacts going to the starting winding. Here the algorithm depends on the type of relay. For posistor models, it is important to make sure that when voltage is applied (which is difficult to do at home without a stand), the circuit opens. However, the absence of a change in resistance after short-term heating with a hairdryer (with caution) will indirectly indicate a malfunction. If the resistance does not change when heated, it means that the posistor has lost its properties.
The table below shows approximate resistance values for various relay states that will help you interpret the device readings:
| Measurement type | Normal reading | Failure sign | Probable cause |
|---|---|---|---|
| Thesistor resistance (cold) | 3 - 50 Ohm | Infinity or 0 Ohm | Open circuit or short circuit |
| Main winding contacts | Close to 0 Ohm | High resistance | Oxidation or burning of contacts |
| Thermal relay (bimetal) | 0 Ohm (closed) | Infinity | The thermal release spiral has burned out |
Step-by-step instructions for replacing the relay
If the diagnostics confirm a malfunction, the next step is to replace the part. This process does not require special skills, but requires compliance with safety precautions and accuracy. The main rule is that all work is carried out only on a completely de-energized refrigerator. Do not neglect this rule, since the risk of electric shock when working with a compressor is real.
First remove the old relay, carefully loosening it from side to side. Do not pull sharply to avoid damaging the compressor's copper pipes or wires. Remember or photograph the location of the wires if there are several of them. They are usually color coded or marked: C (common), R (run), S (start). The new part must fully correspond to the old one in terms of markings and electrical characteristics.
☑️ Checklist before replacing the relay
Install the new relay in place, making sure it is seated tightly to the compressor contacts. Connect the wires according to the diagram or photograph you made earlier. It is important that the connections are secure and not loose. After assembly, do not rush to immediately close the back panel. Plug in the refrigerator and listen: the motor should start confidently without unnecessary clicks and hums.
If the start-up was successful, let the unit run for 10-15 minutes, monitoring the temperature of the compressor housing. It should not heat up to the point where it is impossible to touch it with your hand. Also check if cold appears in the chambers. Only after making sure that it is working properly can you screw on the protective panel and move the refrigerator into place.
Common mistakes during self-repair
One of the most common mistakes is ignoring the cause of the relay failure. Often the relay does not burn out on its own, but due to problems with the compressor, for example, jamming of the piston group. If you simply replace the relay and the motor remains stuck, the new relay will burn out after a few seconds or minutes of operation. Therefore, before installing a new part, it is useful to check whether the motor shaft rotates freely (at least by ear and by the nature of the hum).
Another mistake is using a relay with inappropriate characteristics. Owners of refrigerators Vestel sometimes install universal Chinese analogues, not paying attention to the operation current. This can lead to the relay either constantly clicking without starting the motor, or, conversely, will not open the starting winding, which will lead to the motor burning out.
⚠️ Attention: Never try to “revive” an old relay by stripping the contacts or tapping. Even if the refrigerator starts working after this, the service life of the restored part is calculated in hours, and the risk of fire or compressor breakdown increases many times over.
Also, do not forget about checking the wiring. Oxidized or frayed wires going to the relay can create additional resistance, causing heating and false operation of the protection. Before installing a new element, inspect the terminals and, if necessary, clean them or replace damaged sections of the cable.
Is it possible to temporarily start a refrigerator without a relay?
Theoretically, you can start the motor by applying voltage directly to the starting winding for a short time, but this is extremely dangerous and requires the skills of an electrician. It is strictly not recommended to do this in a domestic environment, as you can easily get an electric shock or burn the compressor windings.
Prevention and extension of service life
In order for the relay and compressor of your refrigerator Vestel to serve for a long time, it is important to ensure correct operating conditions. First of all, this concerns ventilation. The compressor should not be pressed tightly against the wall or covered with cabinets, as overheating contributes to the degradation of the insulation and changes in the properties of the posistor. Regularly wipe the rear grille from dust, which acts as a heat insulator.
The second important factor is the stability of the voltage in the network. Voltage surges can lead to breakdowns in the electrical part of the relay and thermal release. If the lights in your home flicker frequently or the voltage is unstable, it is recommended to connect the refrigerator through a voltage stabilizer or surge protector with surge protection.
Also make sure the door seals are tight. If warm air enters the chamber, the compressor is forced to work longer and more often, which increases the number of on-off cycles. Each switching on is a load on the starting relay. Timely replacement of the seal or door adjustment will help reduce the load on the unit's electrics.
Questions and answers (FAQ)
Is it possible to test a relay without a multimeter?
It is difficult to accurately determine the performance of a posistor without instruments, but an indirect test can be carried out. If, when you turn on the refrigerator, the relay makes a clicking sound, but the motor does not start, and a new known-good relay also does not help, the problem may be in the compressor. If the relay does not click at all and is silent, but the contacts are intact, most likely it is faulty. However, to be 100% sure, a multimeter is needed.
Where can I find the markings for a replacement relay?
The markings are usually applied to the side or top of the plastic relay housing. Look for codes starting with the letters PTC, as well as numbers indicating resistance (eg 15 ohms, 22 ohms) or compatibility with compressor models (Danfoss, Secop, Embraco). Also, the part number can be found in the instructions for the refrigerator Vestel or on the manufacturer’s website for the unit model.
Why does the new relay burn out immediately after installation?
If the new relay burns out instantly, this indicates a serious problem with the compressor itself. Most likely, the piston is jammed or there is an interturn short circuit in the windings, which is why the starting current exceeds the permissible limits by several times. In this case, simply replacing the relay will not help; repair or replacement of the compressor will be required.
How much does it cost to replace a relay in the service?
The cost consists of the price of the part itself (usually from 500 to 1500 rubles) and the work of the technician. In service centers, the price for visiting and diagnostics may vary. Self-replacement allows you to save on work, since the process takes no more than 15-20 minutes.