The situation when the refrigerator stops freezing, and the compressor is either silent or makes only a short click and hums for a couple of seconds, is familiar to many. Often the reason lies not in the breakdown of the motor itself, but in the failure of its “starter” - the starting relay. This small component takes on a colossal load, starting the engine and protecting it from overheating, so its resource, alas, is not endless.
Choosing the right part is not just a trip to the store with the name of the refrigerator brand. The market is replete with universal analogues, but installing an unsuitable element can lead to burning of the motor windings or even a fire. In this article we will look at how to correctly identify a fault, decipher the markings and choose the ideal replacement, based on technical parameters, and not just appearance.
Before you start searching for a spare part, you need to make sure it is safe. Any work on diagnostics and replacement of electrical components should be carried out only after completely disconnecting the device from the network. You should not rely on memory - always unplug the plug from the socket to eliminate the risk of electric shock.
The principle of operation and types of starting relays
To understand what part to buy, you need to understand how it works. Starting relay is an electromagnetic or posistor switch that supplies high voltage to starting winding of the compressor only at the moment of start-up. As soon as the engine reaches the required speed, the relay turns off the starting winding, and the motor runs on the main one.
Modern and old refrigerators use two fundamentally different types of devices. The first type is electromagnetic relays (often found in Soviet models such as “Biryusa” or old “Atlantas”). They are triggered by current flowing through a coil and have a movable core. The second type is posistor (PTC) relays, which have been the standard for technology for the last 20 years. They use a ceramic element that changes resistance when heated.
⚠️ Attention: It is strictly forbidden to replace an electromagnetic relay with a posistor one (and vice versa) without changing the connection diagram. These devices have different operating principles and operating current requirements, which can lead to instant failure of the compressor.It is also important to consider the presence of a built-in one. thermal protection. In many models, the relay is combined with thermal protection, which opens the circuit when the compressor housing overheats. If you buy a relay without protection where it should be, or forget to install a separate “tablet” of thermal protection, the motor will burn out at the first overload.
Diagnostics: is the relay really to blame?
Before looking for the article number of a new part, make sure that this is the problem. Symptoms of a faulty start relay are often confused with a breakdown of the compressor or thermostat itself. The surest sign is a characteristic sound: you hear the refrigerator trying to turn on, there is a loud click, the motor hums for 2-5 seconds, then another click and silence.
For an accurate diagnosis, remove the relay from its seat on the compressor. A visual inspection can immediately give an answer: if soot, melted plastic, or a burning smell is visible inside the housing, the part definitely requires replacement. Also shake the relay next to your ear: if a “stone” rattles inside or a clear knock is heard, it means that the mechanism is destroyed.
- 🔌 Check multimeter: ring the relay contacts - in good condition, the resistance should be either zero (closed) or infinite (open), depending on the type and state of rest.
- 🔥 Thermal protection test: if the relay is combined with protection, check the circuit for an open. At room temperature, the circuit should be closed (resistance close to 0 Ohm).
- 🔨 Mechanical check: for electromagnetic relays, the movable core should move freely inside the coil, without sticking or dangling excessively.
If visually and instrumentally the relay seems intact, but the refrigerator does not start, perhaps the problem is “sticking” of the contacts or loss of the properties of the posistor, which is visible only when voltage is applied. In such cases, replacing with a known good analogue is the fastest way to check.
📊 What symptom is observed in your refrigerator?The compressor hums and clicksThe refrigerator is completely silentThe motor hums, but not startsA cracking sound is heard inside the caseMarking and decoding of parameters
The most reliable way to select a part is to rely on the markings on the body of the old relay. Usually this is a set of numbers and letters that indicate the manufacturer, series and, most importantly, operating current. Ignoring this data turns repairs into a lottery.
The key parameter is rated current. It is indicated by a number, sometimes with a letter (for example, 1.3, 1.6, 2.2, 3.0). This figure indicates the current strength in amperes at which the relay should operate. If you install a relay with a current less than the nominal value, it will constantly click, preventing the motor from starting. If it is more, the starting winding may not turn off, which will lead to overheating.
You can often find manufacturer codes on the case, such as Danfoss, Secop, Indesit or Atlant. It is important to understand that the same code can be found in different brands, but with different characteristics. Therefore, always double-check the current numbers, and not just the logo.
What do the letters in the marking mean?
The letter designations often indicate the type of design: P - posistor, M - electromagnetic, S - with thermal protection. However, the encoding may differ between factories, so it is better to check the correspondence table.
Pay attention to the number and location of contacts. A standard relay has 3 contacts for connecting to the compressor (general, starting, working) and 2 or 3 for connecting to the network and capacitor. An incorrect connection will disable the new part instantly.
Correspondence table of currents and analogues
When looking for a replacement in the store, you may not find the original part with the exact name. In this case, correspondence tables come to the rescue. The main rule for selecting a universal relay: its operating current must fall within the range indicated on the body of the old relay, or be as close as possible.
Below is a table of correspondence between popular series of relays and their operating currents. This data will help you choose an analogue if the original is discontinued.
Series / Marking Operating current (A) Type Compatibility RT (Danfoss/Secop) 1.0 - 1.3 Electromagnetic Old models, low power PTC 110 / 111 1.0 - 1.4 Posistor Universal (Indesit, Stinol) PTC 210 / 211 1.8 - 2.2 Posistor Average power (Atlant, Beko) PTC 310 / 311 2.5 - 3.0 Posistor Powerful compressors 100-136 (K-33) 1.3 - 1.6 Electromagnetic Soviet refrigerators When used For universal relays, carefully read the instructions on the package. Some models have an adjusting screw or switch for adjusting the operating current, which makes them suitable for a wide range of equipment.
Instructions for replacement and installation
The process of replacing the starting relay does not require complex tools, but requires accuracy and attention. The main thing here is not to damage the compressor tubes and to correctly orient the new part.
First remove the rear cover of the refrigerator (crankcase) at the bottom. You will see a compressor - a black “barrel” with tubes. A relay is attached to its protruding shank. Remove the retaining bracket or bar, if present, and carefully pull the relay down. It is removed together with the wiring block.
☑️ Procedure for replacing the relay
Done: 0 / 8The new relay is installed in a position strictly corresponding to the marking. The case usually has an inscription
UPor an arrow pointing up. If you turn the posistor relay over, it may not work or burn out, since there is a moving element or a specific contact design inside.⚠️ Attention: When installing, make sure that the wires do not touch the hot compressor tubes or moving parts (if there is a fan). The insulation of the wires must be intact; use heat shrink if necessary.After connecting, turn on the refrigerator. You should hear the engine starting after a few seconds. If the compressor started working smoothly, without humming or vibration, and after 10-15 minutes cold appeared in the chamber, the repair was successful.
Frequent errors during selection and installation
Even experienced craftsmen sometimes make mistakes that nullify all efforts. The most common of them is an attempt to “fit” the relay by force or using electrical tape. If the connectors do not match, then you have chosen the wrong model. Do not try to bend the contacts or wrap the wires - this is the path to a short circuit.
The second mistake is ignoring the condition of the compressor. If a relay burns out, it is often a consequence, not a cause. The compressor could “leak” (lose freon or become contaminated), which increased the load, and the relay acted as protection. Installing a new relay on a faulty motor will cause re-combustion after a few minutes or hours.
- 🚫 Ignoring the capacitor: if there is a starting capacitor in the circuit, be sure to check it. A swollen or dried capacitor will not allow the motor to start even with a new relay.
- 🚫 Incorrect orientation: as mentioned, the position
UPis critical. In some models, the relay can be placed in only one position physically, in others you need to monitor it yourself.- 🚫 Saving on quality: buying the cheapest Chinese analogs without markings often leads to the fact that the declared current of 2A actually turns out to be 1.5A, which causes unstable operation.
Questions and answers (FAQ)
Is it possible can you start the refrigerator without a starting relay?
Theoretically, you can start the motor by applying voltage directly to the starting winding for a short time, but operating the refrigerator without a relay is strictly prohibited. Without protection and automatic shutdown of the starting winding, the compressor will burn out in a matter of minutes.
Why does the new relay click, but the refrigerator does not turn on?
This may indicate several problems: the operating current is incorrectly selected (too low), the compressor itself is faulty (the mechanism is jammed), or the starting capacitor has failed. It is also worth checking the voltage in the network.
How long does the starting relay last?
The average service life of a high-quality relay is 5-10 years. However, frequent power surges in the network, power outages and work in conditions of high humidity can reduce this period to 2-3 years.
Is it possible to repair a burnt-out relay?
Repairing a starting relay, especially a posistor, is not economically feasible and technically difficult. A posistor is a disposable element. Electromagnetic relays can sometimes be disassembled and the contacts cleaned, but the reliability of such repairs will be low, so only replacement is recommended.