Connecting a refrigerator relay: diagrams, tools and step-by-step repair

The refrigerator relay is a small but critical element that is responsible for starting the compressor and protecting it from overloads. If the refrigerator suddenly stops freezing, hums but does not turn on, or the compressor runs without stopping, the problem may lie in a faulty relay. In most cases, you can replace or connect it yourself, without resorting to the services of a specialist.

However, before taking up a soldering iron or screwdriver, it is important to understand the types of relays (starting, protective, combined), their location in the circuit and connection features for a specific compressor model. In this article we will look in detail at how to correctly connect a refrigerator relay from diagnosing a malfunction to testing after repair. We will pay special attention to popular brands of compressors (Danfoss, Embraco, Secop) and typical mistakes that beginners make.

If you have never dealt with electrical circuits, do not be alarmed: the process of connecting a relay is simpler than it seems. The main thing is to observe safety precautions and follow proven algorithms. And for those who have already tried to repair a refrigerator, but encountered difficulties, we have prepared a unique compatibility table of relays and compressorswhich will help avoid mistakes when choosing a spare part.

Types of refrigerator relays: which one to connect?

Before To start connecting, you need to determine what type of relay you are dealing with. Not only the connection diagram depends on this, but also the tools that will be required for work.

There are three main types of relays installed in refrigerators:

• 🔧 Start relay —responsible for starting the compressor at the moment of switching on. Usually it is a small box with contacts and a spring mechanism. In modern models, it is often combined with a protective relay.
• ⚡ Protective relay - protects the compressor from overheating and power surges. It can be built into a starting relay or installed separately (for example, in the form of thermistor or a bimetallic plate).
• 🔄 Combination relay - combines the functions of starting and protective. The most common option in refrigerators Atlant, Indesit, Samsung and other popular brands.

As a rule, household refrigerators use a combination relay, which is attached directly to the compressor housing. However, in older models (for example, Soviet "ZIL" or "Minsk"), the starting and protective relays can be separated. To avoid mistakes, pay attention to the markings:

If you are not sure about the type of relay, pay attention to the number of contacts:

• 2 contacts - most likely it is protective relay.
• 3 contacts - combined (start-up protection).
• 4 or more contacts - a relay with additional functions (for example, for inverter compressors).

⚠️ Attention: In refrigerators with a system No Frost an additional relay for the fan can be installed. Its connection is different from the compressor connection - do not confuse the diagrams!

Tools and materials for connecting the relay

In order to correctly connect the refrigerator relay, you will need a minimum set of tools. Most of them can be found in the home arsenal, but some will have to be purchased (for example, if you plan to do repairs regularly).

Here is a complete list of what you may need:

• 🔧 Phillips and flat-head screwdriver (for dismantling the compressor cover and attaching the relay).
• 🔌 Multimeter (to check winding resistance and circuit integrity).
• ✂️ Wire cutters or side cutters (for cutting wires).
• 🔥 Soldering iron (power 25–40 W) and solder (if you need to repair contacts).
• 🧲 Voltage tester (indicator screwdriver) for checking power.
• 📏 Pliers (for bending contacts).
• 🔍 Magnifying glass (for inspecting small parts and markings on the relay).
• 📄 Connection diagram (usually pasted on the back wall of the refrigerator or inside the compressor lid).

Also prepare consumables:

• 🔌 Terminals or lugs for wires (if the old ones are oxidized).
• 🧵 Heat shrink tube or electrical tape (to insulate connections).
• 🧴 Alcohol or solvent (to clean contacts from oxidation).
• 🔋 New relay (if the old one cannot be repaired). When purchasing, pay attention to the marking - it must match the original.

⚠️ Attention: If you are working with a refrigerator using refrigerant R600a (isobutane), avoid open flames and sparks when soldering - this gas is explosive! It is better to use a non-contact soldering iron or terminal connections.

Before starting work, be sure to disconnect the refrigerator from the network and discharge the capacitor (if it is in the circuit). To do this, just close its terminals with a screwdriver with an insulated handle.

Connection diagram of the relay to the refrigerator compressor

The relay connection diagram depends on the type of compressor and model of the refrigerator. However, in 90% of cases, a standard three-pin circuit is used, which is suitable for most household units. Let's look at it in detail.

The compressor body usually has three terminals, marked as follows:

• C (Common) — general contact (connected to the mains phase).
• S (Start) — starting winding (connected via the starting relay).
• R (Run) — working winding (connects directly to the network).

The standard connection diagram for a combined relay looks like this:

1. Phase wire (L) is connected to the contact C on the compressor and to the corresponding relay output.
2. The neutral wire (N) is connected to the contact R on the compressor.
3. The starting winding (S) is connected to the relay output responsible for starting (usually labeled as S or Start).

Below is a simplified diagram for visual understanding:

Network 220V
│
L ━━━[Relay]━━━ C (Compressor)
│           │
N ━━━━━━━━━ R
│
S ━━━[Start relay]

To check the correct connection, you can use a multimeter:

1. Set the resistance measurement mode (Ω).
2. Measure the resistance between the terminals C-R (working winding) - should be within 10–40 Ohm.
3. Measure the resistance between the terminals C-S (start winding) - must be within 20–50 Ohm.
4. The resistance between R-S must be equal to the sum of the two previous values (this is a check of the integrity of the windings).

⚠️ Attention: If the resistance between any terminals tends to zero or infinity, this indicates data-i="157">or winding break. In this case, the compressor requires repair or replacement. turn-to-turn short circuit or winding breakage. In this case, the compressor requires repair or replacement.

For refrigerators with inverter compressors (LG, Samsung with technology Digital Inverter) connection diagram may differ - they often use an electronic relay that is controlled by a board. In this case, independent repair is not recommended without special equipment.

Step-by-step instructions for connecting the relay

Now let's move on to practice. Below are universal instructions for connecting a combination relay to a refrigerator compressor. If you have separate starting and protective relays, the steps will be similar, but additional adjustment of the protective mechanism will be required.

Step 1. Dismantling the old relay

1. Unplug the refrigerator and remove the back cover (if there is one).
2. Carefully disconnect the wires from the relay contacts, having previously photographed or sketched their location.
3. Unscrew the mounting screws (usually 1-2 pieces) and remove the relay from the compressor housing.

Step 2. Preparing a new relay

1. Compare the markings of the old and new relay. They must match completely (for example, Danfoss 103N0210).
2. If the contacts are oxidized, clean them with alcohol or fine sandpaper.
3. Install the relay on the compressor and secure with screws (do not overtighten so as not to damage the housing!).

Step 3. Connection wires

1. Connect the phase wire (L) to the contact C on the relay and compressor.
2. Connect the neutral wire (N) to the terminal R on the compressor.
3. Connect the relay start contact (S) with the corresponding terminal on the compressor.
4. Insulate all connections with heat shrink tubing or electrical tape.

Step 4. Check operation

1. Connect the refrigerator to the network.
2. Listen to see if the compressor starts (there should be a characteristic relay click and slight vibration).
3. Check whether the refrigerator is freezing (10-15 minutes after turning it on).

If the compressor does not start, the following problems are possible:

• 🔌 Incorrect wire connection (check the diagram again).
• 🔋 Faulty relay (check it with a multimeter).
• 🔧 Jammed compressor (replacement will be required).

Typical errors when connecting the relay

Even experienced craftsmen sometimes make mistakes when working with refrigerator relays. We have collected the most common ones. common mistakes that can lead to repeated breakdown or even failure of the compressor.

1. Mismatch between the relay and compressor model

Each relay is designed for a specific current and compressor power. For example, the relay Danfoss 103N0120 is suitable for compressors with power up to. 120 W, and 103N0210 - up to 210 W. If you install a relay with less power, it will overheat and quickly fail.

2. Incorrect position of the relay

Some relays (especially with bimetallic protection) are sensitive to orientation in space. If you install it “upside down”, the protective one. the mechanism may operate falsely. Usually there is an arrow on the relay body indicating the correct position.

3. Ignoring contact oxidation

Oxidized contacts increase resistance in the circuit, which leads to overheating and poor starting of the compressor. Always clean the contacts before connecting, even if they look normal.

4. Using a soldering iron without protection

When soldering wires to relay or compressor contacts, it is easy to damage the insulation or overheat the parts. Use a soldering iron with a power of no more than 40 W and work quickly.

5. data-i="212">If the compressor is faulty (for example, the piston is stuck or there is a refrigerant leak), the new relay will also fail. Always check the resistance of the windings before installing the relay.

If the compressor is faulty (for example, a stuck piston or a refrigerant leak), the new relay will also fail. Always check the winding resistance before installing the relay.

6. Incorrect insulation of connections

Bad insulation can lead to a short circuit. adhesive tape - only heat-shrinkable tubing or high-quality electrical tape.

To avoid these mistakes, follow a simple rule: check each action twice.. This is especially true for connecting wires - it is better to check the diagram once again than to look for the cause of the malfunction later.

What to do if the relay clicks, but the compressor does not start?

If the relay clicks, but the compressor does not start, the problem may be the following:

• 🔋 Discharged or faulty capacitor (if it is in the circuit).
• 🔧 Interturn short circuit in the compressor windings.
• 🔌 Low voltage in the network (less than 190 V).
• 🔄 Faulty starting relay (check the coil resistance).

This In this case, additional diagnostics with a multimeter or megohmmeter will be required.

How to check a refrigerator relay with a multimeter

If you are not sure that the relay is faulty, you can check it with a multimeter. This will avoid unnecessary replacement and save time.

Checking a combined relay:

1. Set the multimeter to resistance test mode (Ω, range 200 Ohm).
2. Connect the probes to the contacts C i S (start winding). The resistance should be in the range 10–50 Ohm.
3. Connect the probes to the contacts C i R (working winding resistance should be 5–30). Ohm.
4. Check the circuit between S and R —the resistance should be equal to the sum of the two previous values (this indicates the serviceability of the windings).

Checking the protective relay (bimetallic):

1. Place the relay in the freezer for 10–15 minutes (to cool the bimetallic plate).
2. Ring the relay contacts in a cold state - the circuit should be closed (resistance ~0 Ohm).
3. Heat the relay with a hairdryer or immerse in hot water. When heated, the circuit should open (resistance → ∞).

Checking the starting relay (induction):

1. Remove the relay cover and inspect the coil for breaks or blackening.
2. Ring coil - the resistance should be in the range 50–200 Ohm.
3. Check the moving core - it should move freely without jamming.

If at least one of the tests fails, the relay is faulty and requires replacement. Also pay attention to external signs of a malfunction:

• 🔥 Blackening or melting of the case.
• 💨 Burning smell during operation.
• 🔊 Constant buzzing without clicks (indicates a jammed mechanism).

Features of connecting relays in refrigerators of different brands

Although the principles of connecting relays are universal, some brands of refrigerators have their own nuances.

1. Refrigerators Atlant and Biryusa

Most models of these brands use a combined relay Danfoss 103N or RTK-XFeatures:

• The relay is attached directly to the compressor using a spring clamp.
• In some models (Atlant MXM-1705), the protective relay is placed separately and installed on the frame of the refrigerator.
• When replacing the relay, be sure to check the position up arrows —it should look vertically.

2. Refrigerators Samsung i LG (with inverter compressors)

In models with technology Digital Inverter (for example, Samsung RB-30 J3200) an electronic relay is used, which is controlled by the board. Self-replacement of such a relay not recommended, as it requires configuration through the service menu. Signs of malfunction:

• Error code 5E or 8E on the display.
• The compressor operates jerkily or does not start.

3. Refrigerators Indesit i Ariston

Relays Embraco ER or Asperaare often installed in these refrigerators. Features:

• The relay can be hidden under a heat-insulating casing.
• In models with No Frost a fan relay is additionally installed, which is sometimes confused with a compressor one.
• When replacing the relay, be sure to check capacitor condition —in these brands it often fails in parallel with the relay.

4. Soviet refrigerators (ZIL, Minsk, Oka)

In older models, the starting and protective relays are often separated. Features:

• The starting relay can be induction type (with a coil and core).
• The protective relay is often bimetallic plate in a glass case.
• When replacing the relay, you may need adjustment of the spring mechanism (the instructions for the refrigerator usually have an adjustment diagram).

If you did not find your brand in list, pay attention to the compressor markings. Usually it is applied to its body in the format ABC-123, where:

• ABC — compressor model (for example, Danfoss NL).
• 123 — modification (power, type of refrigerant).

Using this marking you can select a compatible relay in catalogs spare parts.

FAQ: Frequently asked questions about connecting a refrigerator relay

Is it possible to connect a relay from another refrigerator?

Theoretically, it is possible, but only if the relay completely matches the following parameters:

• Type (starting/protective/combined).
• Rated current (must be no lower than the original).
• Contact markings (C-S-R).
• Compressor type (for Danfoss, Embraco or Secop can connectors differ).

If at least one parameter does not match, the relay will quickly fail or will not ensure the correct start of the compressor.

Why does the new relay operate immediately after connection?

This can happen for several reasons:

• 🔌 Short circuit in the compressor windings (check the resistance multimeter).
• ⚡ Power surges in the network (install a stabilizer).
• 🔥 Overheating compressor (let it cool 1-2 hours before turning it on).
• ⚠️ Incorrect relay position (check the orientation along the arrow on the housing).

If the problem persists, the compressor itself may be faulty.

How to check if the compressor is working if the relay is it working?

To check the compressor, follow these steps:

1. Disconnect the relay and apply voltage directly to the compressor windings (phase on C, zero on R).
2. Briefly (for 1-2 seconds!) connect C and S —the compressor should start.
3. If the compressor does not start or makes a strong hum, but does not rotate, this indicates on turn-to-turn short circuit or piston jamming.

⚠️ Attention: Do not apply voltage to the compressor for more than 3 seconds without a relay - this can lead to overheating of the windings!

What to do if, after replacing the relay, the refrigerator works, but does not freeze?

If the compressor starts, but the refrigerator does not cool, the problem may not be in the relay Check:

• 🧊 Refrigerant leak (refilling required).
• 🔄 Thermostat (perhaps it does not give a command to turn on).
• 🌡️ Temperature sensor (in models with electronic control).
• 🔇 Clogged capillary tube (cleaning required).

Also make sure that the relay does not turn off too quickly - this may indicate compressor overheating due to a fan malfunction (in models with No Frost).

Can the relay be repaired or just replaced?

In most cases, the relay can only be replaced, but some faults can be eliminated:

• 🔧 Oxidized contacts —clean them with alcohol or sandpaper.
• 🔩 Weak spring (in induction relays) - can be bent for better contact.
• 🔥 Burnt contacts - clean them with a file or replace with new ones (if the relay is disassembled