How to check the refrigerator start relay yourself: 5 working methods

Has the refrigerator stopped freezing, the compressor does not start or runs jerkily? The reason may lie in a faulty start relay -small but critical unit that is responsible for starting the engine. In 60% of cases of breakdowns associated with lack of cooling, it is to blame. The good news is that you can check the relay yourself without resorting to the services of a technician. This does not require professional skills - just basic knowledge of electrical engineering and a couple of tools.

In this article we will analyze universal algorithm for diagnosing the starting relaywhich is suitable for 90% of household refrigerators (Biryusa, Nord, LG, Eyeko etc.). You will learn how to determine a malfunction by indirect signs, conduct testing with a multimeter, and also what to do if you don’t have measuring instruments at hand. We will pay special attention to the typical mistakes that beginners make when checking - they can lead to false conclusions or even damage to equipment.

Signs of a faulty starting relay: when a check is needed

The starting relay is an “intermediary” between the compressor and the electrical network. Its task is to supply current to the motor windings at the time of startup and turn off after reaching operating mode. If the relay fails, the refrigerator either does not turn on at all or operates intermittently. Here are the key symptoms indicating its malfunction:

• 🔴 The refrigerator does not start, but the light inside is on (which means there is power, but does not reach the compressor).
• 🔄 The compressor tries to start, makes a buzzing or clicking sound, but immediately turns off.
• ❄️ The motor runs for 1-2 minutes and turns off, then the cycle repeats (the relay “releases” the contacts due to overheating).
• 🔥 There is a smell of burning or melted plastic near the compressor.
• ⚡ Traces of melting, cracks or blackening.

It is important to distinguish a relay failure from problems with the compressor or thermostat itself. For example, if the refrigerator does not freeze, but the motor hums continuously, the culprit is most likely thermostat or a freon leak. But if the compressor is “silent” or makes short clicks, the relay is the first candidate for checking.

⚠️ Attention: If the refrigerator is connected through a voltage stabilizer, first check its functionality. Voltage surges are a common cause of relay failure, especially in rural areas or old houses with an unstable network.

Design and principle of operation of the starting relay

To properly check the relay, you need to understand how it works. Most household refrigerators use two types of relays:

1. Electromechanical (induction) - with a coil and a movable core. The principle of operation is based on an electromagnetic field that attracts contacts when the compressor starts.
2. Electronic (posistor) - with a thermistor (posistor), which heats up and opens the circuit after the motor starts. More often found in modern models (Samsung, LG, Bosch).

Regardless of the type, the relay performs three functions:

1. Closes the circuit starting winding of the compressor at the moment of switching on (it is needed for the initial “push” of the rotor).
2. After 1-3 seconds, turns off the starting winding, leaving only the working one working.
3. Protects the compressor from overheating by opening the circuit at critical currents.

Inside the relay case there are:

• 🧲 Coil (in induction models) or posistor (in electronic models).
• 🔌 Movable/fixed contacts.
• 🔧 Spring and core (in mechanical relay).
• 🛡️ Bimetallic plate (for protection against overloads).

The connection diagram is standard: the relay is attached directly to the compressor and connected to it with three wires (common, starting, working). In some models (Atlant, Stinol), the relay can be taken out separately and connected to it. motor with flexible terminals.

Preparation for testing: tools and safety precautions

Before removing the relay, prepare everything you need:

If you don’t have a multimeter, you can get by control lamp (220V, 40–60 W) with two wires. However, this method is less accurate and requires extreme caution - you will be working with a network under the influence. voltage!

⚠️ Attention: Before starting work required disconnect the refrigerator from the network and discharge the capacitor (if it is in the circuit). data-i="128">Attention:

Also follow the rules:

• 🧤 Wear rubber gloves (protection from accidental electric shock).
• 🚫 Do not touch two relay contacts at the same time or compressor.
• 📸 Take a photo of the wire connection diagram before removing them.
• 🔌 Do not turn on the refrigerator with the relay removed - this may burn the compressor windings.

☑️ Preparing to check the relay

Disconnect the refrigerator from the networkDischarge the capacitor (if any)Take a photo of the wire connectionPrepare toolsWear protective gloves

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Method 1: External inspection of the relay - what should alert you

Start with visual diagnostics. Remove the relay from the compressor (usually it is attached with latches or screws) and inspect it from all sides. The following signs indicate a malfunction:

• 🔥 Melted body or traces of burning - indicate a short circuit or overheating of the contacts.
• 💥 Cracks in plastic parts - can lead to moisture or dust getting inside.
• 🧲 Blackening or oxidation of contacts - increases resistance and interferes normal current.
• 🕳️ Deformed or burnt springs/cores (in mechanical relays).
• 💧 Traces of corrosion or moisture inside the case - often happens in refrigerators located in damp rooms.

Pay special attention contact group. In induction relays, the moving contact (“patch”), which closes the starting winding circuit, often burns out. In electronic relays, check the integrity of the posistor - it should be free of cracks and swelling.

If the relay is externally intact, but the refrigerator does not work, proceed to electrical tests. However, remember: the absence of visible damage does not guarantee serviceability. For example, in posistor relays, a thermistor often “dies,” which outwardly looks normal.

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

This is the most reliable diagnostic method. We will check the resistance of the relay windings and the integrity of the contacts. The algorithm is suitable for both types of relays (inductive and electronic), but there are nuances.

Step 1. Removing the relay and identifying contacts

Carefully remove the relay from the compressor. On its case there is usually a connection diagram or pin marking:

• S (Start) - starting winding,
• R (Run) - working winding,
• C (Common) - common contact.

If there is no marking, take a photo, how the wires were connected to the compressor (usually S i R go to the motor terminals, and C to the network wire).

Step 2. Checking the resistance between the terminals

Turn the multimeter to the resistance measurement mode (Ω) to the limit 200 Ohm or 2 kOhm. Ring pairs of contacts:

Pair of contacts	Norm for inductive relay	Norm for electronic relay	What does it mean
S → R	5–20 Ohm	10–40 Ohm	Starting winding resistance
C → R	0 Ohm (short circuit)	0 Ohm (short circuit)	Integrity of the operating circuit
C → S	0 Ohm (in normal condition)	Thesistor resistance (room temperature)	Checking the starting circuit

In electronic relays, the resistance between C and S depends on the temperature of the posistor. At room temperature it should be 10–50 Ohm, and when heated (for example, if you hold the relay in your hand for 1-2 minutes) it should increase sharply (up to hundreds of Ohms or a break). If the resistance does not change, the posistor is faulty.

Step 3. Check for short circuit

Put the multimeter into continuity mode (or to the limit 2 MOhm) and check the resistance between any terminal and metal body of the relay. In a working relay, it should tend to infinity (OL). If the device shows at least some value, there is a breakdown in the case, and the relay must be replaced.

⚠️ Attention: In some models of refrigerators (Stinol 101, Atlant MHM 1705) the relay is combined s thermal fuse. If the multimeter shows an open circuit C → R, check the fuse - it may be burnt out.

Method 3: Checking without a multimeter - using a light bulb

If you don’t have a tester at hand, you can use control lamp (220V, 40–60 W) with two wires. This method is less accurate, but will help identify serious faults: breaks or short circuits.

Important: You will have to work with a voltage of 220V, so be extremely careful. It is better to invite an assistant who will insure and, if necessary, turn off the power.

Step 1. Preparing the test lamp

Take a socket with a light bulb and two wires 30–50 cm long. Strip the ends of the wires and connect them to patron. Connect the second end of one wire to the phase in the socket (check with an indicator screwdriver), and leave the second wire free - it will be a “probe”.

Step 2. Checking the integrity of the circuits

Connect the free wire ("probe") one by one to the relay terminals:

• Touching the C i R, the lamp should burn (integrity of the working circuit).
• Touching the C i S, the lamp should light up and go out in 1-2 seconds (in an induction relay) or burn dimly (in an electronic one, if the posistor is cold).
• If the lamp is not lights up in any case - there is a break in the relay.
• If the lamp is constantly on at C → S the contacts are “stuck” (the relay must be replaced).

Step 3. Check for breakdown

Connect one wire of the lamp to any terminal relay, and the second - to the metal body of the refrigerator (grounding). If the lamp lights up, there is a breakdown in the housing, and the relay is dangerous to use.

⚠️ Attention: This method is not suitable for electronic relays with posistors PTC of the latest generations (for example, in refrigerators LG series No Frost). In them, the circuit C → S may be open even in a cold state, and the lamp will not light up. In this case, you cannot do without a multimeter.

Method 4: Direct test with the compressor (for experienced ones)

If you are confident in your skills, you can check the relay in conjunction with the compressor. This method helps to identify faults that are not visible during a separate test (for example, poor terminal contact or turn-to-turn short circuit in the motor windings).

Step 1. Preparation

Remove the relay from the compressor, but do not disconnect the wires from the motor. Make sure all contacts are clean and tight. If there is oxidation, clean them with fine sandpaper.

Step 2. Supply power directly

Attention: this step requires working with a voltage of 220V. Connect the wires to the relay according to the diagram:

• Phase (L) - to the contact C.
• Zero (N) - to the contact R.

No need to connect anything to the contact - it is closed by the relay only at the start. S you don’t need to connect anything - it closes the relay only at the start.

Step 3. Monitoring operation

Turn on the power. A working relay should:

• 🔊 Make a click (in induction models).
• 🕒 Hold contact C → S 1-3 seconds (the compressor will start humming).
• 🔄 Release contact S, leaving only C → R (the motor will continue to work).

If the compressor does not start or the relay turns off immediately, it is faulty.

Step 4. Checking the current

If you yes current clamps, measure the current consumption of the compressor at startup. Normally, it should be:

• 📈 Starting current: 8–12 A (at the moment of switching on).
• 📉 Operating current: 0.8–1.5 A (after starting).

If the current is significantly higher, there may be problems with the motor windings or an interturn short circuit. If it is lower, the compressor is worn out or the relay does not provide the required voltage.

What to do if the compressor hums but does not start?

This may indicate:

1) A faulty starting capacitor (if it is in the circuit).

2) Interturn short circuit in the compressor windings.

3) "Sticking" of the relay contacts in the open state.

In this case, you need to separately check the capacitor and the resistance of the compressor windings.

Method 5: Replacement relay to a known good one

If all the previous methods did not give an unambiguous result, the most reliable way is to install it on a refrigerator a known working relay with the same compressor. This will eliminate the influence of the human factor (for example, errors in measurements) and will show whether the problem is with the relay.

How to choose an analogue?

The relays must match:

• 🔌 Type: induction or electronic.
• 📏 Dimensions and method of mounting (not all relays are physically interchangeable).
• 🔢 Rated current (indicated on the case, for example, 5A 250V).
• 🔧 Connection diagram (location of pins S, R, C).

For refrigerators Atlant and Stinol relays RL3-1A24P or DANFOSS 103N0012. For Indesit i Ariston — SKM 15/1 or SIP-5.

Where can I get a working relay?

• 🔄 Ask your neighbor (if he has the same refrigerator).
• 🛒 Buy a new one at a spare parts store (costs 300–800 rubles).
• 🔧 Take a used relay from disassembly (check it with a multimeter first).

If after replacing the refrigerator started working, the problem was in the relay. If not, look for a fault in the compressor, thermostat or wiring.

Typical errors when checking relays

Beginners often make mistakes that lead to false conclusions or damage to equipment. Here are the most common ones:

• 🚫 Checking the relay without turning off the compressor —you can burn the motor windings if you apply voltage directly.
• 🔌 Ignoring the capacitor —in some models (Nord, Biryusa) the relay works in tandem with a starting capacitor. If it is faulty, the relay will not operate either.
• 📏 Incorrect measurement limit —if you check the resistance of the windings at the limit 200 kOhm, the multimeter will show break, even if the circuit is working.
• 🔥 Test under voltage without insulation —risk of electric shock or short circuit.
• 🔄 Confusion with the conclusions — if you mix up S and R, the compressor will not start, and the relay may burn out.

Another common mistake is relay diagnostics without taking into account temperature. For example, electronic relays with posistors are tested at room temperature (20–25°C). If you test them in the cold (for example, in an unheated garage), the posistor may show an open circuit, although in fact it is working.

Also do not forget that in some refrigerators (LG, Samsung with inverter compressors) are used specialized control boards, which replace the classic relay. They are checked differently - usually with a multimeter in diode testing mode.

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

If the diagnostics confirmed a relay failure, you have two options:

Method	Pros	Cons	Cost
Repair relay	Cheaper than replacement, suitable for mechanical relays	Not always possible, temporary solution	0–200 rub. (cleaning contacts, soldering)
Replacement with a new one	Reliable, long-term	Requires selection of an analogue	300–1500 rub.
Replacement with a used one	Cheaper than new	Risk of repeated breakdown	100–500 rubles.

When is repair possible?

• 🔧 In induction relays you can clean the burnt contacts with sandpaper or a needle file.
• 🔩 Tighten loose terminals or replace the core spring.
• 🧴 Restore oxidized contacts using alcohol or a special lubricant (for example, Kontakt 60).

When to replace?

• 🔥 In electronic relays a burnt posistor cannot be repaired.
• 💥 Cracks in the body or melting of the plastic.
• 🧲 Interturn short circuit in the coil (in induction relays).

If you decide to replace the relay, buy a model with this same rated current and type of fastening. For example, for refrigerators Atlant a relay is often suitable, and for RL3-1A24P, and for Indesit — SKM 15/1, check the relay brand on the label on the compressor or in the instructions for the refrigerator.

After replacement, check the operation of the refrigerator within 1-2 hours. If the compressor starts without clicks and buzzing, and the temperature in the chamber begins to rise. if it falls, the relay is working properly.

FAQ: Frequently asked questions about checking the starting relay

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

Yes, but this is less accurate. You can:

1. Ring the circuits C → R and C → S with a multimeter right on the spot (turning off the power!).
2. Listen to the clicks of the relay when turned on. refrigerator - if they are not there, the relay does not work.

However, for a complete diagnosis (checking the resistance of the windings, the posistor), it is better to remove the relay.

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

This is a typical situation when:

• 🔋 Discharged or faulty starting capacitor (if it is in the circuit).
• 🔄 The relay contacts are “stuck” in the open state (current does not flow to the starting winding).
• 🔧 Interturn short circuit in the compressor windings (the motor cannot turn over).

Check the capacitor with a multimeter (the resistance should drop from ∞ to 0 when tested) and the resistance of the compressor windings.

How to check the relay for refrigerator