How to check the starting relay of a refrigerator yourself: 3 working methods

When the refrigerator suddenly stops freezing, makes strange clicks or does not turn on at all, the culprit often turns out to be starting relay a small but critical element of the compressor starting system. This part is responsible for supplying voltage to the motor windings at the moment of start, and its failure leads to a complete stop of the unit. In 60% of cases, a relay malfunction can be diagnosed independently, without resorting to the services of a technician - it is enough to have a multimeter and basic knowledge of electrical engineering on hand.

In this article we will analyze three proven methods of checking the starting relay - from visual inspection to testing the resistance of the windings, and also tell you how distinguish a relay malfunction from problems with the compressor or thermostat. You will learn what tools you will need, how to safely dismantle the part, and what to do if the relay is “broken” or burnt out. Let us dwell separately on features of relays for inverter refrigerators —their diagnostics require a different approach.

Signs of a faulty starting relay: when is it time to check

The first signal about possible problems with the relay is unstable operation of the compressor. The refrigerator may turn on for a few seconds and immediately turn off, make loud clicking noises (especially when trying to start) or not respond to the network connection at all. Here are the key symptoms indicating a relay malfunction:

• 🔊 Clicks without starting the engine —the relay is activated, but the compressor does not start (typical of “stuck” contacts).
• ⚡ The refrigerator does not turn on —no response to power supply, although the light inside is on.
• ⏱️ Short operating cycles —the motor starts for 5–10 seconds and turns off (the relay overheats or does not hold the contacts).
• 🔥 Burnt smell —indicates burnt contacts or coil windings relay.
• 📉 Loss of performance —the compressor works, but does not gain the required power (may be due to an insulation breakdown).

It is important to distinguish between relay failure and malfunctions thermostat or compressor. For example, if the refrigerator does not turn on at all, the problem may lie in the thermostat (it does not send a signal to start). And if the engine hums but does not start, the culprit is often compressor starting windingand not the relay. To accurately determine the source of the problem, comprehensive diagnostics will be required.

⚠️ Attention: If the refrigerator is under warranty, disassembling the relay yourself may lead to loss of warranty. Check the conditions at the service center your brand (for example, Indesit, Samsung or Atlant) before starting work.

Design and principle of operation of the starting relay

The starting relay is an electromechanical (or electronic) device that briefly connects starting winding the compressor to the network. Its task is to create additional torque to start the motor rotor. After the compressor picks up speed, the relay turns off the starting winding, leaving only the working winding to work.

In classic refrigerators (for example, Birusa or Stinol) two types of relays are used:

1. Electromechanical (tablets) — with a coil and a movable core. When current is applied, the core is retracted, closing the contacts of the starting winding.
2. Electronic (posistor) - without moving parts, with a thermistor (posistor), which opens the circuit when heated.

The operating scheme is simple:

1. When the refrigerator is turned on, current flows to the working and starting windings through the closed relay contacts.
2. The compressor rotor begins to rotate, the current in the starting winding drops.
3. The relay “feels” the change in current and opens the contacts of the starting winding.
4. The compressor operates normally only on the working winding.

In inverter refrigerators (for example, LG Inverter Linear or Samsung Digital Inverter) starting relays are not used - their role is performed by the electronic control unit. Diagnostics of such systems requires special equipment and skills.

Preparation for testing: tools and safety measures

Before proceeding diagnostics, prepare the necessary tools and ensure safety. You will need:

• 🔧 Phillips/flathead screwdriver — for dismantling the relay cover and fastenings.
• 📊 Multimeter — for measuring resistance and checking the circuit (even a budget model is suitable DT-830B).
• 🔌 Extension cord with a light bulb (control) - to check the presence of voltage (optional).
• 🧲 Pliers - for careful removal of the terminals.
• 📸 Smartphone —to photograph the connection diagram before disassembling.

Safety measures:

• ⚡ Unplug the refrigerator and wait for the capacitors to discharge (5-10 minutes).
• 🧤 Work in dielectric gloves (or at least dry hands).
• 🔍 Do not touch open relay contacts when power is connected.
• 📋 Write down or photograph the location of the wires before disconnecting them.

⚠️ Attention: If your refrigerator is connected through a voltage stabilizer, check it serviceability before relay diagnostics. Voltage surges are a common cause of relay failure, and ignoring this factor will lead to repeated failure after replacing the part.

Method 1: Visual inspection of the relay - what to look for

Start with an external inspection of the relay, even without tools you can identify obvious signs of a malfunction:

1. Smelted case - if the plastic is blackened or deformed, this indicates. for overheating due to a short circuit or breakdown.
2. Burnt contacts —there may be black or green oxidation spots on the copper terminals (especially on the contacts of the starting winding).
3. Cracks or chips —mechanical damage to the case can lead to moisture and corrosion.
4. Smell of burning —even if everything is intact on the outside, the characteristic smell indicates an internal breakdown.

Pay special attention relay coil (in electromechanical models). If it swells or darkens, this is a sure sign of an interturn short circuit. In posistor relays, check the integrity of the thermistor - it should be without cracks or blackening.

Also inspect wiressuitable to the relay:

• 🔌 Loose terminals - can cause sparking and burning of contacts.
• 🔥 Melted insulation - a sign of overheating or short circuit.
• 💧 Traces of corrosion - oxidation of contacts impairs conductivity.

If found obvious damage, the relay must be replaced. However, even with external integrity, the part may be faulty - in this case, a check with a multimeter will be required.

How to distinguish a relay from a thermostat?

The relay is usually located next to the compressor and has 2-3 terminals for connecting wires. The thermostat is located inside the chamber (behind the plastic panel) and is connected to a capillary tube.

Method 2: Testing with a multimeter - step-by-step instructions

To accurately diagnose the relay, use a multimeter in resistance measurement mode (ohmmeter). Follow this algorithm:

Step 1: Removing the relay

Carefully remove the relay from the compressor:

1. Disconnect the wires from the relay terminals (memorize or photograph their location!).
2. Unscrew the mounting screws (usually 1-2 pieces) and remove the relay from the compressor housing.
3. If the relay is in a plastic casing (like Atlant), disassemble it by prying the latches with a screwdriver.

Step 2: Checking the resistance coils

Switch the multimeter to mode 200 Ohm and measure the resistance between the coil terminals (usually these are contacts to which thin wires fit):

• 🔹 Normal resistance: 10–50 Ohm (depending on the model).
• 🔹 Resistance 0 Ohm —short circuit in the coil.
• 🔹 Resistance ∞ (infinity) —open circuit.

Step 3: Checking the contacts

Ring the relay contacts in the “on” position (to do this, apply 220V voltage to the coil through a test lamp or briefly connect the relay to the network):

• 🔹 Between common contact and working the resistance should be 0 Ohm (closed).
• 🔹 Between general and starting contact the resistance should drop to 0 Ohm when the relay is triggered.

If the contacts do not close or the coil resistance is not normal, the relay is faulty.

Step 4: Checking the posistor relay

In a relay with a posistor (thermistor), the algorithm is different:

1. Measure the resistance of the posistor at room temperature - it should be 20–50 Ohm.
2. Heat the posistor with a lighter or hairdryer (carefully!) - the resistance should increase sharply (∞).
3. If the resistance does not change or the posistor is “broken” (0 Ohm), the part must be replaced.

⚠️ Attention: If you are not confident in your skills in working with a multimeter, do not take risks - errors when testing under voltage can lead to electric shock. In this case, it is better to contact a specialist.

Method 3: Checking without a multimeter - alternative methods

If you don’t have a multimeter at hand, you can check the relay in other ways:

Method 1: Replacing with a known good relay

If you have a second refrigerator with a similar relay (or you can borrow a part from a neighbor), temporarily install it instead of the suspicious one. If the refrigerator starts working, the problem is in the relay.

Method 2: Direct start of the compressor

Carefully remove the relay and apply voltage directly to the compressor:

1. Disconnect wires from the relay and remember their location.
2. Connect the starting and operating windings of the compressor directly to the network via an extension cord with a light bulb (for safety).
3. If the compressor starts, the relay is to blame. If not, the problem is in the motor or windings.

Important: This method requires caution - if it is direct. connection, the compressor may burn out if it is jammed. Do not use it for more than 1-2 seconds!

Method 3: Checking the heating

Connect the refrigerator to the network and touch the relay after 5-10 minutes of operation:

• 🔥 If the relay hot (you cannot hold your hand) - there is probably a short circuit or breakdown.
• ❄️ If the relay cold, but the compressor does not start - check coil or contacts.

These methods are less accurate than checking with a multimeter, but can help in emergency situations.

Frequent errors when testing and how to avoid them

Even experienced technicians sometimes make mistakes when diagnosing a relay Here. the most common of them:

• 🔌 Confuse the terminals - connect the wires to the wrong contacts after checking. Solution: always take pictures of the original connection.
• 📊 Wrong multimeter mode - measure coil resistance in voltmeter mode. Solution: use the mode 200 Ohm.
• ⚡ Check under voltage - touch the relay contacts when turned on power supply. Solution: always unplug the refrigerator from the mains!
• 🔧 Strong mechanical impact - they break the latches of the relay housing during disassembly. Solution: use plastic a spatula instead of a screwdriver.
• 🔍 Ignoring the compressor - change the relay without checking the motor windings. Solution: always test the compressor for interturn short circuit.

Another typical mistake is purchase of an incompatible one. relayEven if the part looks similar, it may not fit the parameters:

• 📋 Refrigerator model (for example, Atlant MXM 1705).
• 🔢 Compressor type (marking on the case, for example, Danfoss NL6L).
• 🔌 Rated current (indicated on the relay label, for example 1.2 A).

⚠️ Attention: In some refrigerators (for example Samsung No Frost) the relay is integrated into the control board. In this case, replacing the relay separately is not possible - repair or replacement of the entire module is required.

What to do if the relay is faulty: repair or replacement

If diagnostics have confirmed a faulty relay, you have two options:

1. Repair of the relay (only for electromechanical ones). models)

In some cases, the relay can be restored:

• 🧹 Cleaning the contacts — remove carbon deposits from the contacts with fine sandpaper (zero) or an eraser.
• 🔧 Bending the spring —if the contacts do not close due to a weakened spring, carefully bend it.
• 🔥 Replacing the coil —if there is a break in the coil, it can be rewinded (skills required).

However, repair is a temporary solution. In 80% of cases, a repaired relay fails again within a year.

2. Replacing the relay

For replacement:

1. Buy similar relay (according to the refrigerator or compressor model). Price - from 500 to 2000 rubles.
2. Install a new relay by connecting the wires in accordance with the photo.
3. Check the operation of the refrigerator - the compressor should start without clicks or delays.

The cost of replacing the relay at the service center is 1500–3500 rubles (depending on the model). If you are not confident in your abilities, it is better to entrust the work to a professional, especially for refrigerators with inverter compressors.

After replacing the relay:

• 🔌 Check the voltage in the network - it should be 220–230 V (use a tester).
• ⏱️ Let the refrigerator run idle for 1-2 hours (without food).
• 📝 Write down the date of replacement - this will help track the resource of the new one details.

FAQ: Frequently asked questions about checking the start relay

Is it possible to check the relay without removing it from the refrigerator?

Yes, but only partially. You can measure the coil resistance without removing the relay, but removal will be required to check the contacts and posistor. Also visually inspect the part for melting or cracks. However, full diagnostics is only possible after dismantling.

How to distinguish a relay malfunction from a compressor breakdown?

If the relay is working properly, but the compressor does not start, check:

• Resistance of the compressor windings (between terminals C-S, C-M, S-M). Norm: 10–40 Ohm for the working winding, 20–60 Ohm for the starting winding.
• Compressor current consumption (must be within the range indicated on the nameplate).

If the windings are “broken” or the current is significantly higher than normal, the problem is in the compressor.

How much does a new relay cost and where to buy it?

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

• Electromechanical - 500–1200 rub.
• Posistor - 800–1800 rub.
• For inverter refrigerators - 1500–3000 rub.

You can buy:

• In service centers of your brand (guarantee of original parts).
• In stores of spare parts for household appliances (for example, 220-volt, All-Spares).
• At marketplaces (Yandex Market, Ozon) - but check compatibility!

Can I use a relay from another refrigerator?

Only if it completely matches:

• Type (electromechanical/posistor).
• Rated current (indicated on the case, for example, 1.2 A).
• Connection diagram (terminal location).

Even if the relay is similar in appearance, but is designed for a different current; it may burn out or not work. Always check the documentation!

What to do if, after replacing the relay, the refrigerator works, but gets very hot?

Possible reasons:

• The wires are incorrectly connected (starting and operating windings). swapped).
• The thermostat is faulty (does not turn off the compressor when the temperature is reached).
• The capillary tube is clogged or there is a freon leak (refilling is required).

Disconnect the refrigerator and check the wire connections. If the problem persists, call a technician to diagnose the system. cooling.