Connecting wires to the refrigerator start relay: step-by-step instructions with diagrams

The starting relay is a small but critical element of the refrigerator, which is responsible for starting the compressor. If the wires are connected to it incorrectly, the equipment will either not turn on or will work intermittently, risking burning out. Many owners are faced with the need to reconnect the relay after replacing, repairing or diagnosing faults. However, even experienced craftsmen sometimes confuse contacts, especially when it comes to models with non-standard wiring - for example, Biryusa or Nord.

In this article we will look step-by-step instructions on connecting wires to starting relay, we will consider typical diagrams for different brands of refrigerators, and also warn about common errorsthat can damage the equipment. You will learn how to determine the purpose of each contact, even if there is no marking on the relay, and what tools you will need for the job.

⚠️ Important: If your refrigerator is still under warranty, self-repair may void it. Check the conditions in the service coupon or check with the manufacturer.

1. Design and principle of operation of the starting relay

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

• 🔌 Closes the circuit to start the compressor at the moment of switching on.
• ⚡ Protects the windings from overheating, opening the circuit when exceeded current.

Most household refrigerators use two types of relays:

• 🔧 Electromechanical (with a coil and core) - installed on models Atlant, Stinol, Daewoo.
• 📱 Electronic (with control board) - typical for modern LG, Samsung, Liebert.

When power is applied, the relay closes contacts starting winding of the compressor, providing the necessary rotor torque. After 1-3 seconds, when the engine picks up speed, the relay opens the starting circuit, leaving only working windingto work. If the current exceeds the permissible value (for example, due to a jammed compressor), the relay is activated as thermal and turns off the power.

2. Tools and materials for connection

Before starting work, prepare everything you need. Without the right tools, you risk damaging the contacts or wire insulation:

• ⚡ Multimeter (to check winding resistance and circuit integrity).
• 🔧 Phillips/flat head screwdriver (depending on the relay mounting).
• ✂️ Side cutters or wire cutters (for cutting wires).
• 🔥 Soldering iron with solder (if contact restoration is required).
• 🧲 Heat shrink tube or electrical tape (for insulating connections).
• 📏 Marker and paper (for the connection diagram).

You may also need terminal pullerif the wires are tightly seated in the connectors. Some models (for example Whirlpool) use non-standard connectors - it is better not to break them out, but to carefully loosen them with a screwdriver.

3. Schemes for connecting wires to the relay

The standard connection diagram for the starting relay includes three key wires:

1. Common (common, C) — comes from the refrigerator plug.
2. Working (run, R) —connects to the working winding compressor.
3. Starting (start, S) —goes to the starting winding.

However, depending on the model of the refrigerator and the type of relay, the wiring may differ. Below is a comparison table for popular brands:

⚠️ Attention: Wire colors can vary even within the same brand! Always check with winding resistance (see next section).

4. Step-by-step instructions for connection

Follow this algorithm to avoid errors:

1. Disconnect the refrigerator from the network and discharge the capacitor (if any) by short-circuiting its terminals with a screwdriver with an insulated handle.
2. Take a photo of the original connection wires to relay and compressor. This will help restore the circuit if something goes wrong.
3. Disconnect the relay from the compressor by unscrewing the mounting bolts or releasing the latches.
4. Check the resistance of the compressor windings (see table below).
5. Connect the wires to relay according to the diagram (general - to C, working - to R, starting - to S).
6. Attach the relay to the compressor and connect the power.
7. Turn on the refrigerator and check the operation of the compressor (it should start without clicks or hum).

Resistance of compressor windings (typical values):

All wires are connected according to the diagram|Relay contacts are not oxidized|The relay is securely attached to the compressor|The refrigerator is disconnected from the network during works-->

5. Common mistakes and how to avoid them

Even experienced craftsmen sometimes make mistakes when connecting a relay. Here are the most common of them:

• ⚡ The starting and working ones are mixed up windings - the compressor will hum, but will not start. Solution: change the wires R and S place.
• 🔌 Bad contact in the terminals —leads to heating and melting of the relay. Solution: crimp the terminals with pliers or solder the connections.
• 🔥 Ignoring winding resistance —if you don’t check the compressor with a multimeter, you can burn the relay. Solution: always measure R-S, R-C, S-C.
• ❄️ Work without discharging the capacitor —risk of electric shock. Solution: discharge the capacitor with a screwdriver with an insulated handle.

Critical error: connecting the power wire (220V) directly to the starting winding without a relay. This is guaranteed to burn out the compressor in a few seconds!

If, after connecting the compressor:

• 🔊 It buzzes, but does not start —check the starting winding and capacitor.
• ⚡ Clicks and turns off —the protection may be triggered (check the current multimeter).
• 💨 Works, but does not cool —the problem may be in the refrigerant, not in the relay.

6. Connection features in refrigerators of different brands

Manufacturers often make changes to connection diagrams. Let's consider the nuances for popular brands:

Atlant i Minsk

In these models, the relay is usually attached directly to the compressor with a bolt. The wires come in heat-shrinkable insulation, so when disconnecting, be careful not to damage the wires. If the relay is burned out, check capacitor (often fails along with the relay).

Indesit and Ariston

Electronic relays here are often combined with protective thermal relay. When replacing, be sure to transfer thermal sensor (small cylinder on the wire) to a new relay - otherwise the compressor will overheat.

LG and Samsung

In modern models, the relay can be built into control board. If it fails, it is sometimes cheaper to replace the entire board than to look for a separate relay. Before replacing reset errors in the service menu (see instructions for the model).

Stinol and Bosch

Relays with four contacts are often found here - the fourth goes for additional protection. Don't ignore him! If the new relay has only 3 contacts, use adapter block.

⚠️ Attention: In refrigerators Liebert and some Electrolux relays are used non-standard logic. It is dangerous to connect them without a diagram - contact the documentation or service center.

7. Checking operation after connection

After connecting the relay, you need to make sure that the system is working correctly:

1. Listen to the compressor —it should start smoothly, without rattling or clicking. Normal sound: uniform humming.
2. Check the temperature of the condenser (metal grill on the back of the refrigerator) - after 10-15 minutes it should be warm, but not hot.
3. Measure the current in the circuit compressor with a multimeter (in AC 10Amode). The norm for most models is 0.8–1.5 A.
4. Make sure that the relay does not heats up - after 30 minutes of operation, its temperature should not exceed 50–60°C.

If the compressor starts, but turns off after a few seconds, the following problems are possible:

• 🔋 Insufficient voltage in the network (check the socket).
• 🧊 Compressor jammed (replacement will be required).
• 🔌 Malfunction of the starting capacitor (replace with one of a similar capacity).

FAQ: Frequently asked questions about connecting the relay

220V ——[Lamp]—— C (general)
|
R/S (working/starting)