Connecting the refrigerator compressor: diagram, tools and step-by-step instructions

The compressor is the “heart” of the refrigerator, and its correct connection determines the performance of the entire system. If you are faced with the need to replace or initially install this unit (for example, after purchasing used equipment without a compressor), it is important to understand not only the sequence of actions, but also the nuances of electrical connections, sealing and testing. Errors at this stage lead to freon leaks, overheating of the windings or complete failure of the unit.

In this article we will examine three key aspects: how to physically connect the compressor to the refrigeration circuit, how to correctly connect it to the electrical network (including circuits for inverter and linear models), and how to check the performance after installation. The material is relevant for most household refrigerators - from Soviet ZIL and Minsk to modern ones. If your model is equipped with a system LG, Samsung And Beko. If your model is equipped with No Frost or has two compressors (for example, Atlant MXM-2835), pay attention to the individual recommendations in the relevant sections.

Before you begin to work, evaluate your strength: connecting a compressor requires skills in soldering copper pipes, working with a vacuum pump and a multimeter. If you have never dealt with refrigeration equipment, it is better to entrust the task to a professional - the cost of an error (for example, moisture getting into the system) can exceed the price of a new compressor.

Refrigerator compressor design: what you need to know before connecting

A refrigerator compressor is a sealed electric motor with a piston system that compresses the refrigerant (freon) and moves it along the contour. Regardless of the model (linear, inverter or rotary), it has three key elements for connection:

• 🔌 Electrical terminals - usually three pieces: C (common), S (starting winding), R (working winding). On inverter models (Samsung Digital Inverterthere may be a connector for the control board.
• 🔧 Freon tubes —input (from the evaporator) and output (to the capacitor). The diameter and location depend on the compressor model (for example, they are different). Freon pipes are spring shock absorbers or rubber suspensions that dampen vibration. In older models ( Embraco EGX And Secop (Danfoss) SC15F they are different).
• ⚙️ Fastening elements — spring shock absorbers or rubber suspensions that dampen vibration. In older models (Donbass-10), the compressor was rigidly attached to the frame.

Before purchasing a new compressor, check its compatibility with the old system using three parameters:

1. Refrigerant type: modern models work on R134a or R600a (isobutane), and old ones - on R12 or R22. You cannot mix freons: this will lead to breakdown compressor and leakage through incompatible seals.
2. Cooling capacity: must correspond to the chamber volume. For example, for a refrigerator Indesit BIAA 13 (250 l) a compressor with a power of 80–100 W is suitable.
3. Electrical parameters: voltage (220 V or 12 V for camping models) and starting winding current. Check them in the passport of the old compressor.

⚠️ Attention: If you are replacing a compressor in a refrigerator with a system No Frost (for example, LG GA-B489YGQZ), keep in mind that the circuit may have two fans and an additional defrost heater. Their connection requires a separate circuit.

Tools and materials for connecting the compressor

To install the compressor, you will need a specialized tool. Some items (for example, a vacuum pump) can be rented, but most tasks are performed by a standard set:

Additionally prepare:

• 🛠️ Set of wrenches — for attaching the compressor to frame.
• 🧲 Magnet —to avoid losing small parts (springs, nuts) inside the body.
• 📏 Vernier calipers —for measuring the diameter of tubes (important when replacing fittings).
• 🧴 Soap solution - to check the tightness of connections.

Step-by-step instructions: how to connect a compressor to a refrigeration circuit

The process of connecting a compressor is divided into three stages: mechanical installation, soldering of tubes and checking for leaks.

1. Dismantling the old compressor

If you are replacing the compressor:

1. Disconnect the refrigerator from the network and discharge the capacitor (if any).
2. Cut the tubes with wire cutters close to the compressor, leaving a margin of 2-3 cm for soldering.
3. Disconnect the start relay (usually secured with latches or screws).
4. Remove the mounting bolts and remove the compressor.

2. Installing a new compressor

Before installation:

• 🔄 Check that the arrow on the compressor body indicates the direction of movement of freon (from the evaporator to the condenser).
• 🛑 Do not drop the compressor - this may damage the internal valves.
• 🔧 Attach it to the frame using original shock absorbers (if they are worn, replace).

For soldering tubes:

1. Sand the ends of the tubes with sandpaper and treat with flux.
2. Place heat-shrinkable tubes on the tubes (protection against oxidation).
3. Solder the connections with a propane torch, avoiding overheating (copper should melt, but not burn).
4. After cooling, check the tightness with a soap solution (bubbles will indicate a leak).

3. Evacuating the system

Before charging freon, it is necessary to remove moisture and air:

1. Connect the vacuum pump to the service port (usually on the filter drier).
2. Turn on the pump for 15-20 minutes. The pressure gauge should show a pressure below -0.1 bar.
3. Close the valve and turn off the pump. If the pressure does not rise for 5-10 minutes, the system is sealed.

⚠️ Attention: If after evacuation the pressure rises quickly, then there is a leak, check all solderings and, if necessary, repeat the process.

Electrical connection of the compressor: diagrams and nuances

The electrical part is the most critical stage. Errors in connecting the windings lead to combustion of the compressor or tripping of the protection. Let's consider two typical circuits.

Scheme for linear compressors (classic models)

Most refrigerators (Atlant, Indesit, Biryusa) use a starting relay that connects the starting winding (S) only for the first seconds of operation. Typical scheme:

~220V
|
C (general)
|
/ \
R   S
|    \
|     START RELAY
|
THERMOSTAT

Connection order:

1. Connect the terminal C to the phase (via the thermostat).
2. Terminal R —to the neutral wire.
3. Terminal S —to the starting relay (usually there is a marking on it Start).

Scheme for inverter compressors

Inverter models (Samsung RB30J3000WW, LG GB-B399SLQB) are controlled by a board that smoothly regulates the rotation speed. There is no starting relay - instead, a connector for the board is used. Connection example:

~220V
|
CONTROL BOARD
|
┌───┐
│ C │
│ R │
│ S │
└───┘

Important:

• 🔌 Do not connect an inverter compressor directly to the network - this will disable it.
• 📱 Before installation, take a photo of the original circuit or find it in the service manual (for example, for Samsung DA97-08004A).
• 🔄 The polarity of the connection to the board matters - reversed wires will lead to an error E1 or E2.

How to check the compressor windings with a multimeter?

Set the multimeter to ohmmeter mode (200 Ohm). Measure the resistance between the terminals:

- C-R: 10–30 Ohm (working winding)

- C-S: 20–50 Ohm (start winding)

- R-S: sum C-R i C-S (for example, 30 + 20 = 50 Ohm)

If the resistance is 0 or ∞ - the winding is closed or broken.

Freon charging and testing the system

After evacuation, the system is ready for charging. To do this:

1. Connect the freon cylinder to the service port through the pressure manifold.
2. Open the valve. cylinder and fill the refrigerant in portions of 10–15 grams, controlling the pressure (for R134a working pressure on the low pressure side is 0.3–0.5 bar).
3. Turn on the compressor for 5–10 minutes and check the temperature of the condenser (should be warm) and the evaporator (should be covered frost).

Signs of correct refueling:

• ❄️ The evaporator is evenly covered with ice.
• 🔊 The compressor operates without extraneous noise (no knocking or rattling).
• 📉 The pressure on the pressure gauge is stable (without jumps).

⚠️ Attention: If after refueling the compressor turns off after 1-2 seconds, two problems are possible: incorrect amount of freon (overcharging) or a malfunction of the thermostat. Check the resistance of the thermostat in a cold state - it should be close to 0 Ohm.

Typical errors when connecting a compressor

Even experienced technicians make mistakes that lead to repeated repairs. Here are the most common:

Pay special attention filter-drierIt must be replaced every time the system is depressurized, as it is saturated with moisture. Otherwise, moisture will enter the compressor and cause a process in which the oil decomposes, forming acids that destroy the windings. oil hydrolysis - a process in which oil decomposes, forming acids that destroy the windings.

Connecting a compressor in refrigerators with two chambers

In two-chamber refrigerators (Atlant MXM 2808, Samsung RT-43K6030S8there can be two compressors (one for each chamber) or one with a separate cooling system. In the first case, each compressor is connected independently, in the second, it is used solenoid valve, switching the freon flow between. cameras.

Installation features:

• 🔄 When replacing one compressor, vacuum only its circuit (close the line to the second chamber).
• 📶 Check the operation of the solenoid valve: when turned on, it should make a click.
• ⚖️ Fill freon equally between the chambers (usually 50/50, but check in the manual).

If after repair one of the chambers does not cools, the reasons may be the following:

• 🔌 The solenoid valve is faulty (check the winding resistance - it should be 200–500 Ohms).
• 🧊 Blockage in the capillary tube (blowing with nitrogen is required).
• 📉 Lack of freon in the circuit (refill by monitoring the weight on the scales).

FAQ: Frequently asked questions about connecting a compressor

Is it possible to connect a compressor from one refrigerator to another?

Theoretically, yes, but only if three parameters match: freon type, cooling capacity and electrical characteristics (winding resistance). For example, a compressor from Indesit BIAA 13 (R134a, 90 W) is suitable for Beko CN 325120 provided that the volumes of the chambers are comparable. However, it is better to use an original spare part - this guarantees compatibility with the control system.

How to determine that the compressor burned out?

Signs of a compressor malfunction:

• 🔌 Doesn't turn on at all (no relay click).
• 🔥 Smells like burning (burnt winding).
• 📉 Works, but does not create pressure (wear of the piston group).
• 🔊 It hums strongly, but does not start (the rotor is jammed).

For diagnostics, turn off the compressor and measure the resistance of the windings. If there is conductivity between any terminal and the housing, the compressor is “broken” and requires replacement.

Do you need to change the oil in the compressor when replacing?

Yes, if:

• 🔄 You change the type of freon (for example, from R12 to R134a).
• 🕒 The compressor has worked for more than 10 years (the oil loses its properties).
• 💧 Moisture has entered the system (the oil has become cloudy).

To change the oil:

1. Drain the old oil by turning the compressor with the valve down.
2. Fill in new oil of the same type (for example, Emkarate RL68H for R134a).
3. Rotate the compressor shaft manually (so that the oil is distributed).

The oil volume is indicated on the compressor nameplate (usually 200–300 ml).

What to do if after connecting the compressor is it heating up?

Slight heating of the compressor housing (up to 60–70°C) is normal. But if it overheats (the hand does not tolerate it) or turns off due to overheating, check:

• 🔌 Network voltage - low voltage (below 200 V) causes overheating of the windings.
• 🧊 Amount of freon —undercharging leads to increased load.
• 🔄 Fan operation capacitor —if it does not spin, the compressor does not cool.
• 📉 Winding resistance —if it is below normal, an interturn breakdown is possible.

To check, use a thermal imager or an infrared thermometer. Temperatures above 90°C are critical—turn off the refrigerator and look for the cause.

Is it possible to connect a compressor without a vacuum pump?

No, this is a gross mistake. Without vacuuming, moisture remains in the system, which:

• 💧 Reacts with freon, forming acids (destroying the compressor).
• ☁️ Freezes in the capillary tube, blocking circulation.
• 🔥 Causes corrosion of copper tubes.

An alternative to a vacuum pump is nitrogen purge, but it is less effective. If the pump is not available, contact service.