Refrigerator relay: device, purpose and signs of malfunction

When the refrigerator suddenly stops freezing or starts making suspicious clicks, many users are the first to It's the compressor that's at fault. However, in 80% of such cases, a completely different device is to blame - start-protective relay. This small box, attached to the compressor housing, performs critical functions: it starts the motor, protects it from overload and prevents overheating. Without a relay, even a working compressor will not be able to operate for more than a few seconds.

In this article we will look in detail at Why do you need a relay in the refrigeratorhow it is arranged inside, what types of relays there are (inductive, posistor, electronic) and by what signs you can determine its breakdown. You will also find out whether it is possible to do without a relay during an emergency start of the refrigerator and which models (Atlant, Indesit, Stinol, LG) most often suffer from problems with this part. The material will be useful for both beginners and those who have already tried to repair household appliances on their own.

What is a relay in the refrigerator and where is it located?

The starting protection relay is an electromechanical (or electronic) device that performs two key functions:

• 🔹 Starting the compressor — it supplies a short-term current pulse to the starting winding of the motor to overcome the inertia of the rotor.
• 🛡️ Overload protection — turns off the power if the compressor overheats or consumes too much current (for example, when jammed).

The relay is located, as a rule, next to the compressor - either screwed directly to its body (in older models), or installed on the frame of the refrigerator and connected by wires. Externally, it is a plastic box the size of a pack of cigarettes, from which 2–4 contacts extend. In modern refrigerators (Samsung No Frost, Bosch VitaFresh), the relay is often integrated into the electronic control unit, but the principle of operation remains the same.

Interesting fact: in Soviet refrigerators (ZIL, Minsk, Biryusa) the relay was mechanical and made a characteristic loud click when activated. In new models, this sound is almost inaudible due to the use of posistors (semiconductor elements).

How a refrigerator relay works: operating principle step by step

To understand why do you need a relaylet's figure out how it interacts with compressor. The entire work cycle can be divided into 4 stages:

1. Power supply. When the thermostat (or electronic unit) closes the circuit, current flows to the operating winding of the compressor. However, the motor cannot start immediately - it needs additional “pushing” force.
2. Triggering of the starting winding. The relay connects starting winding the compressor through the capacitor for a split second. This creates the torque necessary to overcome the inertia of the rotor.
3. Disconnecting the starting circuit. As soon as the rotor picks up speed (usually after 1–3 seconds), the relay opens the starting winding - further work occurs only through the working one.
4. Overload protection. If the current in the working winding exceeds the norm (for example, due to freon leakage or piston jamming), the bimetallic plate in the relay heats up and opens the circuit, saving the compressor from combustion.

In modern refrigerators (Liebert, Electrolux) instead of mechanical ones relays are often used posistor (with a semiconductor element) or electronic (with a microcircuit). They more accurately control the current and are less susceptible to wear, but they are more difficult to diagnose without special equipment.

What is a posistor in a refrigerator relay?

A posistor is a semiconductor element whose resistance increases sharply when heated. In a relay, it acts as a “circuit breaker”: during normal operation, current flows freely, but if the compressor is overloaded, the posistor heats up and opens the circuit. The advantage over a bimetallic plate is the absence of moving parts and higher reliability.

Types of relays: how to determine which one is in your refrigerator

All refrigerator relays are divided into 3 main types. Their appearance and operating principle are very different, so before replacing it is important to correctly identify the model.

You can determine the type of relay by the following characteristics:

• 🔧 Induction: metal case with a spring and a movable core, makes loud clicks.
• 🔥 Posistor: plastic case with the inscription PTC or Posistor, often black.
• 📱 Electronic: compact unit with a microcircuit, can be built into the control board.

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Signs of a relay malfunction: when it’s time to sound the alarm are typical.

A relay failure manifests itself in a very specific way, and it is easy to confuse it with a malfunction of a compressor or thermostat. Here are key symptoms that with a 90% probability point specifically to the relay:

• ⚡ The refrigerator does not turn on, but the light inside is on (which means there is power, but the compressor does not start).
• 🔊 Clicks every 5–10 seconds - the relay tries to start the compressor, but it does not “grabs.”
• ❄️ The compressor runs for 1–2 seconds and turns off (typical for protection activation).
• 🔥 The relay body is hot —a sign that the bimetallic plate or posistor overheat.
• 💡 Indication light blinks with pauses (in models with electronic control).

Important: if the refrigerator does not respond at all when plugged in (no light, the display does not work), the problem is more likely in the surge protector or power supply, and not in the relay.

Check if there is power in the outlet (connect another device)

Listen if the relay makes clicks when you try to start

Touch the relay body - it should not be scalding hot

Inspect the contacts for melting or rust

Try to lightly tap the relay (sometimes it helps with stuck contacts)-->

Is it possible to start the refrigerator without relay: temporary solutions

If the relay is faulty and there is no way to replace it right now, you can use emergency starting methods. However, remember: this is a temporary solution that can lead to compressor overheating!

Method 1: Direct connection of the compressor (only for induction relays):

1. Disconnect the refrigerator from the network.
2. Remove the relay from the compressor.
3. Find 3 pins on the compressor: C (common), S (starter), R (working).
4. Connect power directly to C i R, and then briefly (for 1-2 seconds) touch S k Cto start the motor.

Method 2: Using a starting capacitor (for posistor relays):

If the relay burnt out, but the capacitor is intact, you can temporarily connect the compressor directly through the capacitor. Scheme: Network → Capacitor → Starting winding (S). But this method requires knowledge of electrical engineering!

⚠️ Attention: Prolonged operation of the compressor without a relay will lead to its overheating and failure. The maximum emergency start time is 1–2 hours, after which be sure to disconnect the refrigerator from the network!

How to test a refrigerator relay with a multimeter: step-by-step instructions

For accurate diagnostics of the relay, you will need a multimeter (tester). The check takes 5–10 minutes and consists of 3 stages:

1. Checking the resistance of the windings:

• Disconnect the relay from the compressor.
• Switch the multimeter to resistance measurement mode (200 Ω).
• Measure the resistance between the terminals:
  • C–S (starting winding) - it should be 20-40 Ohm.
  • C–R (working winding) - should be 10-20 Ohm.
  • S–R - should be the sum of the two previous values (30-60 Ohm).

2. Checking the integrity of the contacts:

In the “continuity” mode, check whether the relay contacts close when shaken (for induction models). If the multimeter does not show a short circuit, the contacts are burnt.

3. protection activation:

Connect the relay to the network through a light bulb (as a load). If the light lights up and goes out after 5-10 seconds, the protection is activated (the relay is working properly). If the light does not light up or is constantly on, the relay is faulty.

⚠️ Attention: When checking the induction relay, do not touch the contacts with your bare hands - the voltage is at the starting point. winding can reach 380 V!

How to choose a new relay: compatibility and popular models

When purchasing a new relay, it is important to consider:

• 🔧 Compressor type (for example, Danfoss NL/NF, Embraco EG/NE, Secop).
• 📏 Compressor power (indicated on the nameplate, for example, 1/5 HP or 140 W).
• 🔌 Relay type (induction, posistor, electronic).
• 🔄 Main voltage (220–240 V for Russia).

Here is a relay compatibility table for popular brands of refrigerators:

When purchasing, pay attention to originality of the part - Chinese analogues (for example, XQ-2L) often fail after 1-2 month. It is better to take relays of the same brands as the compressor (Danfoss, Embraco, Secop).

⚠️ Attention: Parts for refrigerators with the system No Frost (for example, Samsung RB or LG GB) often have unique relays that are incompatible with regular models. Check with the seller!

FAQ: Frequently asked questions about refrigerator relays

Is it possible to repair the relay yourself, or just replace it?

Mechanical (induction) relays sometimes fail repair: you can clean the contacts with sandpaper or bend the bimetallic plate. PTC and electronic relays cannot be repaired - only replacement. In any case, the repair gives a temporary effect (1-3 months), so it is better to immediately buy a new relay.

Why does the relay click, but the compressor does not start?

This sign:

• Compressor jamming (check if the shaft rotates manually).
• Open winding in the starting winding (check with a multimeter).
• Insufficient voltage in the network (should be no lower 190 V).

If the compressor is working, but the relay clicks - most likely it is faulty.

How much does it cost to replace a relay in a service center?

The cost of work depends on the type of relay and model of the refrigerator:

• Replacement of an induction relay: 1500–2500 ₽.
• Replacement posistor/electronic relay: 2000–3500 ₽.
• Diagnostics (if you are not sure of the reason): 500–1000 ₽.

Independent replacement will save money, but requires caution - incorrect connection can burn the compressor.

What will happen if you do not change the faulty relay?

The consequences depend on the type of failure:

• If the relay does not start the compressor the refrigerator simply will not work, the food will melt.
• If the relay does not turn off the protection — the compressor will overheat and burn out (repair will cost $ 8000–15000 ₽).
• If the relay periodically “buggy” - this will lead to temperature surges and spoilage of products.

Where to buy a relay for a refrigerator?

Optimal options:

• 🛒 Official service centers (6-12 month warranty, but 20-30% more expensive).
• 🌍 Online stores (AliExpress, Beru.ru, 220-Volt.ru) - cheaper, but there is a risk of running into a fake.
• 🔧 Shops of spare parts for household appliances (for example, "Rembytekhnika", "Cold-Service").

Before purchasing, check the relay labeling with the data on the compressor nameplate!