How to properly connect the RKT-2 relay to the refrigerator: a step-by-step guide with diagrams

The relay RKT-2 is one of the most common start-protection devices for compressors of household refrigerators. Its task is to start the compressor engine and protect the windings from overheating during prolonged operation or overload. However, incorrect connection can lead to failure of both the relay itself and the compressor, which will result in expensive repairs.

In this article we will look at how to connect relay RKT-2 to refrigerators of different brands (Atlant, Indesit, Stinol etc.), what tools will be needed, and what to pay attention to during installation. You will also find schemes connections, typical mistakes of beginners and answers to frequently asked questions about setup. If your refrigerator does not turn on, hums or turns off after a few seconds, the problem may be in the relay.

Before starting work, make sure that the fault lies in the relay and not in the compressor or thermostat. To do this, you can temporarily connect a known working relay (for example, from another refrigerator) and check whether the behavior of the equipment changes. If yes, feel free to start replacing.

What is RKT-2 relay and why the refrigerator needs it

Relay RKT-2 (stands for compressor relay current) is an electromechanical device that performs two key functions:

• 🔌 Starting function: when the compressor is turned on, the relay supplies voltage to the starting winding, helping the engine overcome inertia and start rotating.
• 🔥 Protective function: if the current in the working winding exceeds the permissible values (for example, due to a jammed compressor), the relay opens the circuit, preventing overheating and fire.

Externally RKT-2 it is a plastic case with terminals for connecting wires. Inside are located:

• 🧲 Coil with a movable core (electromagnet)
• 🔧 Contact group (normally open/closed contacts)
• 🔄 Bimetallic plate (for thermal protection)

Differs from similar relays (for example, RKT-1 or DHR) RKT-2 differs:

Important: the RKT-2 relay is not interchangeable with the RKT-1 or DHR without modifications! Connecting an incompatible relay can lead to burnout of the compressor windings.

Tools and materials for connection

To replace or connect the relay yourself RKT-2, prepare:

• ⚡ Phillips and flat-head screwdriver (for dismantling the compressor cover)
• 🔧 Pliers (for crimping terminals)
• 📏 Multimeter (for checking winding resistance and circuit integrity)
• 🔌 New relay RKT-2 (current suitable for your compressor)
• 🧵 Insulating tape or heat shrink tube (for insulating connections)
• 🔍 Flashlight (lighting the back of the refrigerator)

If you buy a relay separately, pay attention to the marking. For example, RKT-2-1.5 is designed for current 1.5 A, and RKT-2-2.5 is for 2.5 A. data-i="123">) suitable version forAtlant, Biryusa, Nord) suitable version for 2.0–2.5 A.

Disconnect the refrigerator from the network

Discharge the capacitor (if yes)

Take a photo of the current connection diagram

Check the compressor windings with a multimeter

Select a relay according to the current-->

Warning: before work, be sure to discharge the capacitor (if it is in the circuit of your refrigerator) To do this, short-circuit its terminals! a screwdriver with an insulated handle. Otherwise, you risk getting an electric shock.

The connection diagram of the RKT-2 relay to the compressor

A typical connection diagram RKT-2 looks like this:

1. Terminal "C" (Common) —common contact, connected to the mains phase (220 V).
2. Terminal "P" (Run) —goes to the working winding of the compressor.
3. Terminal "S" (Start) —connects to the starting winding of the compressor.

On the compressor body there are usually three terminals, marked:

• C —common terminal
• S — starting winding
• R — working winding

If there is no marking, you can determine the windings with a multimeter:

1. Measure the resistance between all pairs of terminals.
2. Maximum resistance (for example, - this is C + S (general + launcher).
3. Medium resistance (15–25 Ohms) is C + R (general + working).
4. The minimum resistance (5–10 Ohms) is S + R (starting + operating).

Below is a table with typical resistance values for compressors of different brands:

What to do if the resistance of the windings does not correspond to the norm?

If the resistance of one of the windings is equal to 0 Ohm (short circuit) or ∞ (break), the compressor is faulty and requires replacement. Connecting a relay to such a compressor is pointless - it is either not. will work, or will immediately turn off due to overload.

Standard connection diagram:

220V network
│
├───┬───[RKT-2]───┬─── Compressor
│   │              │
Phase───C R─── Working winding
Zero───────────────────S─── Starting winding

Step-by-step instructions for connection

Follow this algorithm to avoid errors:

1. Disconnect the refrigerator from the mains and wait until the capacitor discharges (5-10 minutes).
2. Remove protective cover from the compressor (usually secured with 1-2 screws).
3. Disconnect the old relay, having previously photographed or sketched the wire connection diagram.
4. Check the compressor windings with a multimeter (as described above).
5. Connect a new relay according to the diagram:
   • 🔌 Terminal C connect the relay to the phase wire network.
   • 🔄 Terminal R — with the operating winding of the compressor (R or M).
   • ⚡ Terminal S — with the starting winding (S).

Secure the relay on the compressor housing (usually it is fixed with a latch or screw).

Check the operation: turn on the refrigerator and listen to whether the compressor starts. If the relay clicks, but the compressor does not hum, there may be a connection error.

Attention: if after connecting the relay immediately turns off with a characteristic click, this may mean:

• ❌ Incorrect connection of the windings (S i R switched places).
• ❌ Compressor jamming (check if the shaft rotates manually when the power is off).
• ❌ Relay and compressor current mismatch (for example, RKT-2-1.5 on a compressor with a current of 2.2 A).

Typical errors when connecting and how to avoid them

Even experienced technicians sometimes make mistakes that lead to damage to the relay or compressor. Here are the most common:

• 🔌 The starting and operating windings are mixed up:

  If you connect S instead of R (and vice versa), the compressor will not start, and the relay will operate for protection. Always check the resistance of the windings with a multimeter!

• 🔧 Poor contact in the terminals:

  Oxidized or loosely clamped wires cause heating and false protection activation. Clean the contacts with sandpaper and crimp the terminals with pliers.

• 🔥 Using a relay with the wrong current:

  The relay on 1.5 A will not pull the compressor with current 2.2 A —it will overheat and turn off. Check the markings on the compressor!

• ⚡ Ignoring the capacitor:

  In some refrigerators (Stinol, LG) between terminals C and S a starting capacitor is installed. If it is not connected, the compressor will not start.

Practical example: compressors are often installed in refrigerators Atlant data-i="234">with a current of 2.0 A. If you install a relay DKhM-3 with a current of 2.0 A. If you install a relay RKT-2-1.5, it will turn off after 10-15 minutes of operation due to overload. The correct choice is RKT-2-2.0 or RKT-2-2.5.

⚠️ Attention: in refrigerators with the system No Frost (for example, Samsung or Bosch) can use an electronic relay instead of a mechanical one. In this case, replacing it with RKT-2. In this case, replacing with RKT-2 without modifying the circuit is unacceptable!

How to check the functionality of the relay after connection

After installing the relay, you need to make sure that it is functioning correctly:

1. Turn on the refrigerator go online and listen:
   • ✅ Normal: the relay clicks once (closes the contacts), the compressor starts and runs smoothly.
   • ❌ Malfunction: the relay clicks repeatedly (chirps), the compressor does not start or turns off after a few seconds.
2. Check the temperature of the relay housing after 10–15 minutes of operation:
   • ✅ Normal: slightly warm (up to 40–50°C).
   • ❌ Fault: hot (you cannot hold your hand) - a sign of overload.

Measure the compressor current current clamps (if any):

• ✅ Norm: current corresponds to the relay rating (for example, 1.8–2.2 A for RKT-2-2.0).
• ❌ Malfunction: current exceeds the rating by more than 20% - the compressor is overloaded.

If the relay operates too often (once every 1-2 minutes), the following reasons are possible:

• 🔌 Low voltage in the network (less than 200 V).
• 🔄 Freon leak (the compressor works non-stop, trying to gain temperature).
• 🔥 Compressor jamming (the shaft does not rotate, the current increases sharply).

Frequently asked questions about connecting the RKT-2 relay

Is it possible to connect RKT-2 instead of RKT-1?

Technically, yes, but only if the rated current is the relay corresponds to the compressor current. RKT-1 is designed for lower currents (0.8–1.2 A), therefore RKT-2 (1.5–2.5 A) is suitable for more powerful compressors. However, pay attention to terminal dimensions - they may not match.

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

There are several reasons:

1. The compressor starting winding is faulty (check the resistance between C and S).
2. There is no contact in the terminal S relay.
3. Low voltage in the network (less than 180 B).
4. The compressor shaft is jammed (try to turn it manually).

What relay current should I choose for the Atlant refrigerator?

For most models Atlant with compressors DXM-3 or DXM-5 suitable relay RKT-2-2.0 or RKT-2-2.5. The exact current value is indicated on the compressor nameplate (for example, 2.0 A).

Is it possible to connect a relay without a capacitor?

If there was a capacitor in the original circuit of the refrigerator, it needs to be connected! Without it, the starting current will be insufficient and the compressor will not start. The capacitor will not start. data-i="315">required Necessarily need to connect! Without it, the starting current will be insufficient and the compressor will not start. The capacitor is connected between the terminals C And S relay.

What to do if the relay gets hot?

Overheating of the relay indicates:

• Exceeding the rated current (replace the relay with a model with a higher current).
• Bad contact in the terminals (strip and crimp the wires).
• Turn-to-turn short circuit in the compressor windings (check the resistance).

If the relay heats up to 60°C and above, it needs to be replaced urgently - this is a fire hazard!