When the refrigerator suddenly stops freezing or makes suspicious clicks, the first thing that comes under suspicion is relay a small but critically important detail. However, not every user has any idea what it looks like or where to look for it. Externally, the relay can easily be confused with other elements of the compressor unit, especially if you first looked under the back cover of the equipment.
In this article we will analyze visual differences between the start-up protection and thermal relay, show them in real photos (including popular models Atlant, Indesit, Samsung), explain why they break and how check their functionality without calling a technician. We will also warn against dangerous diagnostic errors that can lead to a short circuit or failure of the compressor.
Spoiler: if your refrigerator is It clicks, but does not start, or the motor hums, but does not cool - with an 85% probability the problem is in the relay. And yes, you can replace it yourself, even without experience working with electrics.
What is a relay in a refrigerator and why is it needed?
A relay in a refrigerator is a “switch” of the compressor, which controls its operation based on a signal from thermostat. Without it, the motor will either not start or will run continuously, which will lead to overheating and breakdown. Modern models use two types of relays:
- 🔧 Start-protective relay —starts the compressor and protects it from overloads. It is located directly on the motor housing.
- ❄️ Thermostat (thermostat) — controls the temperature in the chamber and sends a signal to turn it on/off. Most often hidden behind the control panel.
The main difference: start-protective relay always located next to the compressor (usually in a black plastic case with wires), and thermal relay can be built into the temperature control knob or hidden under a decorative cover.
Interesting fact: in old Soviet refrigerators (for example, ZIL or Minsk) the start-protection relay was often made in the form a separate block with a spring and contacts. In modern models it is more compact and reliable, but still vulnerable to power surges.
What a start-up protection relay looks like: photo and description
A start-up protection relay is a small plastic box (usually black or gray) attached to compressor from the side or from above. Its dimensions vary from 3x5 cm to 5x7 cm, depending on the refrigerator model. Main visual features:
- 🔌 Has 3-4 outputs for wires (usually red, black and white colors).
- 🔊 When working, it emits characteristic clicks —this triggers the switching mechanism compressor.
- 📏 Often marked with inscriptions:
PTC,POS,DANFOSSor the manufacturer's logo (for example, Embraco).
The photo below shows a typical start-up relay for refrigerators Atlant and Beko:
Please note: in some models (for example, LG No Frostthe relay may be built into the compressor not visible externally. In this case, for diagnostics you will need to remove the rear cover of the engine compartment.
Where is the thermostat (thermostat) in the refrigerator
The thermostat is responsible for maintaining the set temperature and is usually located in one of three places:
- Inside the refrigerator compartment —under the plastic cover next to the light lamp (typical for Indesit, Ariston).
- Behind the control panel —if your model has electronic control (for example, Samsung RL-33).
- On the evaporator —in models with the system
No Frost(the thermostat is attached to the evaporator tube).
Externally, the thermostat looks like a small box (2x3 cm) with capillary tube (thin copper or plastic hose), which leads to the evaporator. an adjusting screw or switch with numbers from 1 to 7.
Example of location in refrigerators Biryusa i Stinol:
⚠️ Attention: If you remove the thermal relay to check, do not pull the capillary tube — it breaks easily, and then you will have to change the entire thermostat. Disconnect only the wire connectors!
How to distinguish the relay from other parts of the refrigerator
Beginners are often confused relay with capacitor, starting contactor or even control unit. To avoid mistakes, use this table:
| Part | Appearance | Location | Symptoms of malfunction |
|---|---|---|---|
| Start-protective relay | Plastic box 3×5 cm with wires | On the compressor | The refrigerator does not turn on, it clicks |
| Thermostat | Box 2x3 cm with a capillary tube | B chamber or behind the panel | The compressor does not turn off/on |
| Condenser | Cylinder with two terminals (sometimes in a metal case) | Next to the compressor | The compressor hums, but does not start |
| Control unit | Board with microcircuits and wires | Behind the control panel | Indicators do not work, errors on the display |
Simple test: if the part clicks when you turn on the refrigerator is a 100% start-up relay. If it is reacts to changes in temperature (for example, when you turn the thermostat knob), then you have a thermostat.
What to do if the relay is externally intact, but the refrigerator does not work?
Even if there is no visual damage to the body, the relay may be faulty from the inside. For example, in start-up relays the contacts often burn out or the spring breaks. In this case, only replacement or professional diagnostics will help. with a multimeter.
Signs of a relay malfunction: when it needs to be checked
The relay does not break down immediately - it is usually preceded by “symptoms” that can be noticed in advance:
- 🔊 The refrigerator clicks, but does not start is a classic sign of a faulty starting relay.
- ❄️ The compressor works without stopping —the fault is the thermal relay, which does not turn off the motor.
- ⚡ The refrigerator turns on every other time —the relay contacts are burnt or oxidized.
- 🔥 A burning smell appears - immediately turn off the equipment! This is a sign of a short circuit in the relay.
If you observe at least one of these symptoms, do not delay diagnostics. the relay often leads to failure of the compressor, and replacing it will cost 5–10 times more than a new relay.
⚠️ Attention: If the refrigerator electric shock When you touch the housing, the problem is not in the relay, but in the breakdown of the compressor insulation or wiring. In this case, independent repair is dangerous!
How to check a refrigerator relay without special tools
You can pre-diagnose the relay at home, even without a multimeter. Here are the step-by-step instructions:
1. Unplug the refrigerator
2. Remove the cover from the compressor
3. Carefully remove the relay (do not pull the wires!)
4. Look at the contacts to see if there is any carbon deposits or melting
5. Shake the relay to see if it is rattling inside (a sign of breakdown)-->
To check the thermal relay:
- Find the capillary tube and gently warm it with your hands (or put it in warm water).
- If the relay is working properly, you will hear light click —the contact is triggered.
- If there is no click, the thermal relay is faulty.
For accurate diagnostics you will need a multimeter. Test algorithm:
- Set the device in the mode
continuity. - Touch the relay contacts with the probes (the diagram can be found in the instructions for the refrigerator).
- If there is resistance tends to zero —the contacts are closed (the norm for the on state).
- If the resistance infinitely —the relay is faulty.
Is it possible to repair the relay yourself or just replace it?
Theoretically, some relay breakdowns can be eliminated at home:
- 🔧 Oxidized contacts - cleaned sandpaper or alcohol.
- 🔩 Loose fastening - tightened with a screwdriver.
- 🧲 Sticking of the core (in electromagnetic relays) - sometimes light tapping on the body helps.
However, in 90% of cases relay repair is a temporary solution. The fact is that inside the part there are springs, bimetallic plates and contacts that wear out over time. Even if you managed to “reanimate” the relay, it will not last long.
The cost of a new relay for popular models:
- Atlant, Beko - from 500 to 1,200 rubles.
- Samsung, LG - from 1 500 to 2,500 rubles.
- Universal relays (for example, Danfoss 103N0012) - about 800–1,500 rubles.
Replacing a relay takes 10–15 minutes and does not require special skills. The main thing is disconnect the refrigerator from the network and take a photo of the wiring diagram before disconnecting them.
FAQ: Frequently asked questions about the relay in the refrigerator
❓ Is it possible to turn on the refrigerator without a relay?
No, it's dangerous! Without a start-up relay, the compressor will not start, and without a thermal relay it will run continuously and overheat. As a last resort, you can temporarily close the relay contacts (for example, for diagnostics), but not longer than 5–10 minutes.
❓ Why does the relay click, but the refrigerator does not turn on?
This is a sign that the start-up relay is triggered, but the compressor does not start. The reasons may be: 1) a malfunction of the compressor itself; 2) low voltage in the network; 3) capacitor failure. We need comprehensive diagnostics.
❓ What is the service life of the relay?
On average - 5–10 years, but depends on operating conditions. The relay fails faster with: frequent power surges, compressor overheating, high humidity (for example, if the refrigerator is in a damp room).
❓ Is it possible to use a relay from another refrigerator model?
Only if it completely matches the technical parameters: voltage, current, type of compressor. For example, a relay from Atlant is not suitable for Indesit, even if they look similar. It is better to buy an original part or a universal relay with suitable characteristics.
❓ Why did the new relay quickly break down?
Most often this happens due to: 1) unstable voltage in the network (a stabilizer is needed!); 2) compressor malfunction (for example, interturn short circuit); 3) incorrect connection of wires. If the relay burns out within a month, look for the cause in the compressor or electrics.