How to start the refrigerator compressor: video instructions and step-by-step analysis

Starting the refrigerator compressor is a critical procedure that must be performed after repair, replacement of a part, or long-term downtime of the equipment. Incorrect actions can lead to repeated breakdownshort circuit or even fires. In this article we will analyze not only the theoretical part, but also provide video instructions with explanations for different models of refrigerators - from Soviet "ZIL" to modern Samsung No Frost.

We will pay special attention diagnosis before starting: how to check the motor windings, the pressure in the system and the integrity of the starting relay. Without these steps, even a working compressor may not start or burn out after a few minutes of operation. And if you have never encountered the repair of refrigeration equipment, our list of required tools and safety measures will help you avoid typical beginner mistakes.

1. When is forced start of the compressor required?

The compressor is the “heart” of the refrigerator, and its forced start is not always necessary. Here are the main situations when this procedure is justified:

• 🔧 After replacing the compressor on a new or used one (even if it is working, correct connection and testing is required).
• ⚡ After repairing the electrical part: replacing the starting relay, thermostat or control board.
• ❄️ After long inactivity (more than 1 month) - the oil in the compressor may have drained and needs to be "bleeded".
• 🔄 When diagnostics of faults: if the refrigerator does not freeze, but the compressor does not start.
• 🧰 After refilling with freon —to check the tightness of the system.

⚠️ Attention: If the compressor buzzes, but does not start - this may be a sign interturn short circuit or a malfunction of the starting capacitor. In this case, forced starting without diagnostics will lead to final breakdown of the motor.

Most modern refrigerators (LG, Atlant, Indesit) have protection against incorrect starting. If you try to turn on the compressor bypassing the standard circuits, the system may block operation until the error is reset through the service menu.

2. Preparing for launch: tools and safety measures

Before starting work, prepare everything you need. Lack of at least one tool may lead to injury or equipment breakdown.

⚠️ Attention: If you are working with R600a refrigerant (used in most modern refrigerators), remember: it explosive if there is a leak in a closed room. Before starting the compressor, be sure to ventilate the room and make sure there is no gas odor.

Also check:

• 🔌 Network voltage —it should be stable (220V ±5%). Jumps can burn the motor windings.
• 🌡️ Compressor temperature - if it is hot, let it cool for 30-40 minutes.
• 🔧 Fixing the compressor - it should not hang out, otherwise vibration will damage the tubes.

Checked the voltage in the socket|The compressor is secured and does not wobble|Insulated tools|The room is ventilated (when working with freon)|Thermostat is turned off (if forced start is required)-->

3. Diagnostics of the compressor before starting

Before starting the compressor, you need to make sure that it functional and ready for use. Skipping this step is the most common cause of repeated breakdowns.

First unplug the refrigerator and remove the back cover to gain access to the compressor. It looks like a black metal tank with tubes and a terminal block.

Step 1. Checking the winding resistance

Using a multimeter, measure the resistance between the compressor terminals:

• 🔹 Between C (common) and S (start winding) — there should be 20-40 Ohm.
• 🔹 Between C and R (working winding) — 10-20 Ohm.
• 🔹 Between S and R - the sum of the two previous values (30-60 Ohm).

If the readings equal to 0 - short circuit, if infinity - open. In both cases the compressor needs to be replaced.

Step 2. Check for breakdown on the housing

Set the multimeter to the "continuity" mode and check the resistance between each terminal one by one and metal housing of the compressor. If the device shows any value except infinity the compressor is broken and dangerous for use.

Step 3. Visual inspection

Check:

• 🔍 Integrity of the tubes —there are no cracks or signs of corrosion.
• 💧 Traces oil —if the compressor “sweats” oil, this is a sign of oil seal wear.
• 🔥 Darkening on the terminals —speak of overheating and possible interturn short circuit.

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

If the motor hums, but does not start pumping freon, there is a problem may be:

1. Faulty start relay —check its resistance (should be ~10-15 Ohms).

2. Low pressure in the system —possibly a freon leak.

3. Stuck rotor —try to manually rotate the compressor shaft (through the pulley, if there is access).

If the problem remains after replacing the relay, you will need professional diagnostics with a pressure gauge.

4.

If the diagnostics did not reveal any problems, you can proceed to launch. Let's consider two methods: standard (via a thermostat) and forced (direct connection).

Method 1. Normal start (recommended for beginners)

1. Connect all the wires back to the compressor (if you removed them for diagnostics).
2. Make sure that thermostat (or electronic board) is connected and working.
3. Plug in the refrigerator. The compressor should start automatically if the thermostat closes the circuit.
4. Listen to the sound: normal operation - even humming without clicks or knocks.

Method 2. Forced start (for diagnostics)

This method is used if you need to check the compressor bypassing the thermostat. Attention: do not leave the compressor operating in this mode for more than 5 minutes - this can lead to overheating!

1. Disconnect the wires from starting relay (usually it is attached directly to compressor).
2. Connect the compressor directly to the network via starting relay (or use a starter button, if it is in the circuit).
3. Short-term (on 1-2 seconds) apply voltage to starting winding (S), then leave only working (R).
4. If the compressor starts and starts pumping, the problem is in the thermostat or control board.

🎥 Video instructions for starting:

• 📺 Starting the Atlant refrigerator compressor (step by step with comments).
• 📺 Checking the compressor multimeter (for beginners).
• 📺 Forced start-up without a relay (only for experienced ones!).

5. Common mistakes and how to avoid them

Even experienced technicians sometimes make mistakes when starting the compressor. Here are the most common of them and ways to prevent them:

⚠️ Attention: If you replaced the compressor with a used one, be sure to flush the system with a special solvent. Remains of old oil and metal shavings can clog the capillary tube and damage the refrigerator.

Another typical problem is incorrect winding connection. If you mix up the starting (S) and working (R) terminals, the compressor will hum, but will not start. Always check the diagram, which is usually pasted on the compressor housing.

6. Starting the compressor after replacing freon

If the reason for the repair was refrigerant leakage, then starting the compressor has its own nuances. Here it is important not only to connect the motor correctly, but also monitor the pressure in the system.

Step 1. Evacuate the system

Before charging freon, it is necessary to remove moisture and air from the system. To do this:

1. Connect vacuum pump to the service port.
2. Pump out the air to pressure -0.1 MPa (vacuum).
3. Close the valve and leave the system under vacuum for 15-20 minutes to check the tightness.

Step 2. Filling with freon

Use only the type of refrigerant indicated on the refrigerator nameplate (usually R134a or R600a). Fill slowly, monitoring the pressure with a pressure gauge:

• 🔹 Discharge pressure (red scale) - 10-15 bar.
• 🔹 Suction pressure (blue scale) - 0.2-0.5 bar.

Step 3. Test run

After refueling:

1. Connect the compressor according to the diagram.
2. Turn on the refrigerator and watch the pressure gauge.
3. If the discharge pressure rises higher 20 bar - immediately turn off the compressor! This is a sign refilling or a blockage in the system.

🎥 Video on the topic:

• 📺 Evacuating the refrigerator before refueling
• 📺 How to refill freon R600a with your own hands

7. Features of starting in different models of refrigerators

The design of compressors and connection diagrams may differ depending on the brands and years of manufacture refrigerator. Let's consider the key features for popular brands.

Refrigerators Atlant and Stinol (Russian production)

• 🔧 Use compressors DXM or Secop (previously Danfoss).
• 🔌 The starting relay is usually built into compressor (not removable).
• ⚡ To force start, you can use the button on the relay (if there is one).

Refrigerators Samsung i LG (electronically controlled)

• 📱 Starting the compressor controlled control board.
• 🔧 Forced start is possible only through service menu (button combination depends on the model).
• ⚠️ In case of errors on the display (for example, E1 or FF) the compressor is blocked until the code is reset.

Old Soviet refrigerators (ZIL, Minsk, Biryusa)

• 🕰️ Compressors are used KV-6, KV-8 or FG-0.12.
• 🔌 Start relay removable, often fails.
• 🔧 To start, you can use starter button (if the relay is faulty).

⚠️ Attention: B refrigerators No Frost (for example, Indesit NBA 18), the compressor may not start due to a malfunction defrost timer or evaporator heater. Before diagnosing the motor, check these elements.

8. What to do if the compressor does not start?

If after all manipulations the compressor refuses to start, proceed as follows algorithm:

1. Check the power:
   • 🔌 Is there voltage at the outlet?
   • 🔌 Is the power cord damaged?
   • 🔌 Is the fuse on the board (if any) intact?
2. Diagnose the starting relay:
   • 🔊 When you turn on, is there a clicking sound? If not, the relay is faulty.
   • 🔧 Check the resistance of the relay coil (should be ~10-15 Ohm).
3. Ring the compressor:
   • 🔹 Is the winding resistance normal?
   • 🔹 Is there a breakdown on the housing?

Check the thermostat:

• 🌡️ When you turn the thermostat knob, do you hear a click?
• 🔧 Close the thermostat contacts directly - if the compressor starts, the thermostat needs to be replaced.

If all the elements are working, but the compressor does not start, the following are possible:

• 🔋 Faulty control board (in electronic models).
• 🧲 Compressor shaft jammed (try turning it manually).
• ❄️ Clogged in the capillary tube (cleaning or replacement required).

🎥 Useful videos for diagnostics:

• 📺 The compressor hums, but not starts up - causes and repairs
• 📺 How to check the refrigerator control board

FAQ: Frequently asked questions about starting a compressor

❓ Is it possible to start a compressor without a starting relay?

Technically yes, but this extremely dangerous. The starting relay is needed in order to:

• 🔹 Short-circuit the starting winding at the moment of start.
• 🔹 Protect the motor from overheating.

Without a relay, the compressor can burn in a few minutes. If the relay is faulty, replace it with a similar one (for example, RP4 for most household refrigerators).

❓ How long should the compressor operate after starting?

Normally, the compressor operates in cycles:

• 🔹 First start after repair - 5-10 minutes (until it reaches the desired temperature).
• 🔹 In normal mode - 10-20 minutes of operation, then 20-30 minutes of rest.

If the compressor is running continuously for more than 1 hour - this sign:

• 🔸 Freon leaks.
• 🔸 Thermostat malfunctions.
• 🔸 Blockage in the capillary tube.

❓ How to start a refrigerator compressor without freon?

Start the compressor without freon it is strictly prohibited! This will lead to:

• 🔥 Overheating of the motor (freon cools the compressor from the inside).
• 💥 Destruction of seals and oil leakage.
• 🔧 Breakdown of compressor valves.

If you need to check the compressor, fill the system with at least a minimum amount of freon (or nitrogen for testing).

❓ Why does the compressor start and immediately turn off?

The most common reasons:

1. The protective relay is triggered due to:
• 🔹 Overheating of the windings (check the resistance).
• 🔹 Interturn short circuit.

Low pressure in the system (freon leak or blockage).

Malfunction of the starting capacitor (if it is in the circuit).

For diagnostics:

• 🔧 Check the temperature of the compressor housing (should be warm, but not hot).
• 🔊 Listen to whether the relay clicks when turned off.

❓ Is it necessary to add oil when replacing the compressor?

Yes, required! Reasons:

• 🔹 The new compressor comes without oil (or with a minimum amount).
• 🔹 Old oil may be contaminated with wear products.

Recommendations:

• 🔧 Use the same type of oil as in the old compressor (usually PAG or mineral).
• 🔧 Fill 200-300 ml (the exact volume is indicated in the instructions for compressor).