How to independently check whether the refrigerator engine is working: step-by-step guide

Has the refrigerator stopped freezing, is it humming too loudly, or is it not turning on at all? In 80% of cases, the problem lies in compressor the heart of the unit, which is responsible for the circulation of the refrigerant. But before you take your equipment to a service center or buy a new motor for 5-15 thousand rubles, you should make sure that it is the one to blame. This article will help diagnosis of the refrigerator engine without special education - with the help of available tools and basic instruments.

We will disassemble unique signs of a compressor malfunction, which are often confused with thermostat failures or freon leaks, learn how to check the windings with a multimeter, listen to characteristic sounds and even determine the performance of the motor without dismantling it. The instructions are suitable for models Atlant, Indesit, Samsung, LG, Beko and other popular brands - taking into account their design features.

Important: if your refrigerator is under warranty, independent diagnostics with disassembling the case can cancel. In this case, limit yourself to external checks (sections 2 and 3) and contact the service center.

1. Primary diagnosis: signs of a faulty compressor

Before you take up the tools, inspect the refrigerator for “symptoms” that clearly indicate problems with the engine. Here are the key signals:

• 🔊 No sounds when turned on. Normally, the compressor produces a slight hum (with new models it is almost inaudible). If the refrigerator is completely silent, but the light inside is on, this is an alarming sign.
• ❄️ It doesn’t freeze, but the light works. If the chambers are warm and the power indicator is on, the problem is most likely in the motor or start relay.
• 🔥 The compressor is overheating. Touch the black cylinder at the back of the refrigerator (this is the motor) - if it is hot as boiling water and turns off after 5-10 minutes, this is a sign of an interturn short circuit.
• ⚡ Clicks without starting. The characteristic sound of the relay operating, after which the motor does not start, indicates a breakdown of the winding or a jammed piston.
• 💡 The refrigerator turns on and immediately turns off. Does the cycle last 1-2 seconds? This protective relay cuts off the power due to a short circuit in the windings.

Pay attention to the work and rest time compressor. Normally, the motor runs for 10-20 minutes, then turns off for 5-10 minutes. If the cycles have become chaotic (for example, works for 2 minutes, rests for 30), this may indicate:

• 🔋 Compressor wear (loss of performance)
• 🧊 Freon leak (the motor is trying to “catch up” the cold, but not copes)
• 🌡️ Thermostat malfunction (gives false commands to turn on/off)

⚠️ Attention: If the refrigerator Samsung or LG with the system No Frost stops freezing, but the fan in the freezer is spinning - the problem may not be in the compressor, but in defrost timer or the evaporator heater. In this case, engine diagnostics will not help.

2. Testing without instruments: what can be done “by eye and ear”

Not everyone has a multimeter or resistance tester at hand. Fortunately, some compressor problems can be identified without tools. Here is a step-by-step algorithm:

Step 1: Checking the power supply

Make sure that the refrigerator connected to the outlet and it is working (check with a light bulb or other device). Inspect the cord for kinks, melts, or damaged insulation. If the plug or socket gets hot, the problem may be in the contacts, not in the motor.

Step 2: Test for mechanical jamming

Unplug the refrigerator. Carefully turn the compressor by hand using the flywheel (if accessible). Normally, it should turn with slight resistance, without squeaks or jams. If the flywheel does not rotate or requires a lot of force, the motor jammed (replacement will be required).

Note: In modern models Liebert or Electrolux the flywheel may be covered with a casing. Do not try to remove it by force - it’s better to proceed to checking with a multimeter.

Step 3: Diagnostics by sound

Turn on the refrigerator and listen:

• 🔇 Silence —there is no power to the compressor (check the thermostat, relay, wiring).
• 💥 Loud click and silence —the protection is triggered (short circuit or winding break).
• 🔄 Humming for 2-3 seconds and shutting down —the motor tries to start, but cannot (possibly jammed or low voltage in network).
• 🌀 Continuous humming without shutting down — the compressor works, but does not create pressure (wear, freon leak).

If the sound is accompanied casing vibration, this may indicate loosening of the motor mounts or wear of the shock absorbers. In this case, it is enough to tighten the bolts or replace the rubber dampers.

3. Checking the compressor with a multimeter: step-by-step instructions

For accurate diagnostics you will need multimeter (even a budget model for 300-500 rubles will do). We will check winding resistance and circuit integrity. Here's how to do it:

Step 1: Access to compressor contacts

Unplug the refrigerator. Remove the rear cover (if equipped) or protective cover from the compressor. On the motor you will see a box with 3 contacts (usually marked with letters C, S, R):

• C - common contact (common)
• S - starting winding (start)
• R - working winding (run)

If there are no markings, take a photo of the location of the wires before disconnecting them!

Step 2: Checking the resistance of the windings

Switch the multimeter to the resistance measurement mode (Ω) to the limit 200 OhmMeasure the resistance. between contacts:

Example: if during measurement C ↔ S the multimeter shows 1 (break) or 0 (short circuit), the compressor is faulty and requires replacement.

Step 3: Check for breakdown on the case

Switch the multimeter to mode “continuity” (diode icon). Touch each contact one by one (C, S, R), and the second one - metal housing of the compressor (clean the paint first).

• 🚫 Audio signal or resistance < 1 MOhm - breakdown on the housing. for life! Immediately unplug the refrigerator.
• ✅ No signal (resistance = ∞) - insulation is normal.

⚠️ Attention: If the compressor “breaks through the housing”, its operation is prohibited! This may result in electric shock when touching the refrigerator.

Disconnect the refrigerator from the mains|Remove the protective casing|Record the location of the wires|Measure C-S, C-R, S-R|Check for breakdown on the body-->

4. Diagnostics of the starting relay: why the motor does not start

In 30% of cases, a “dead” compressor is actually working - the problem is in start relaywhich supplies current to the starting winding. This is a small box attached to the compressor (sometimes built into it).

How to check the relay:

1. Remove the relay from the compressor (disconnect the wires, remembering their location!).
2. Shake it - if something rattles inside, this is a sign of mechanical wear.
3. Look at the contacts: if they are burnt or coated, the relay is faulty.
4. Check the resistance between the relay contacts in a normally open state with a multimeter. Normally, it should be ∞ (break).

For models Indesit and Ariston there is a problem with posistor (thermistor) in the relay. If there is a malfunction, it does not heat up and the compressor does not start. You can check it by measuring the resistance:

• 🔥 In a cold state: 20–50 Ohms.
• 🧊 After heating (for example, with a hairdryer): the resistance should increase sharply (> 1 kOhm).

If the posistor “does not heat up” or its resistance does not change, replace the relay assembly (costs 500–1500 rubles).

How to temporarily start a compressor without a relay?

If the relay is burned out and you need a refrigerator urgently, you can manually apply current to the starting winding on 1–2 seconds. To do this:

1. Disconnect the relay from the compressor.

2. Connect the wires from the network to the contacts C (common) and R (working winding).

3. For 1–2 seconds, touch the wire from S (start winding) to the phase.

4. The compressor should start. After this, immediately remove the wire from S!

⚠️ This is a dangerous method! Risk of electric shock and damage to the compressor. Use only as a last resort.

5. Checking the pressure: how to make sure that the compressor is pumping

If the compressor is humming, but the refrigerator is not freezing, it may be does not create the required pressure due to wear on the piston group or a freon leak. You can check this in two ways:

Method 1: Tactile test

Turn on the refrigerator and wait until the compressor starts working. Carefully touch:

• 🔥 Discharge tube (thin, hot) - should heat up to 60–80°C.
• ❄️ Tube suction (thick) - should be cold or covered with condensation.

If the discharge tube is barely warm and the suction tube is at room temperature, the compressor does not pump. freon. Reasons:

• Wear of valves or piston.
• Clogged capillary tube.
• Refrigerant leak.

Method 2: Pressure gauge (for advanced)

If you have pressure manifold (used for refilling air conditioners), you can measure the pressure:

1. Connect the pressure gauge to service port (usually on the tube discharge, closed with a cap).
2. Turn on the refrigerator. The discharge pressure should be 10–15 bar (depending on the model and type of freon).
3. If the arrow barely moves or shows < 5 bar the compressor is faulty.

⚠️ Attention: Do not try to “top up” freon yourself! Without special equipment and knowledge, you can damage the system. Contact the specialist.

6. Common mistakes during diagnostics: what not to do

When checking a compressor, beginners often make mistakes that lead to false conclusions or damage to equipment. Here's what you can't do:

• ❌ Check the compressor “for spark”. Connecting the motor directly to 220V without a relay can burn the windings.
• ❌ Knock on the compressor. This does not “reanimate” a jammed motor, but only aggravates the breakdown.
• ❌ Ignore freon leak. If the compressor works but does not freeze, first check the tightness of the system (signs: oil stains, corrosion on tubes).
• ❌ Change the compressor without checking the capacitor. In models with inverter motors (Samsung, LG), the capacitor on the control board often fails, and not the compressor itself.

Another common mistake is confuse a compressor malfunction with a thermostat failure. If the refrigerator turns on but quickly turns off, first check the thermostat:

1. Find the thermostat (usually inside the chamber, behind the plastic panel).
2. Remove the wires from it and short them together.
3. If the compressor starts, the problem is in the thermostat, not in the motor.

7. When the compressor can still be saved: signs of “treatable” breakdowns

A faulty compressor does not always require replacement. In some cases, it can repaired or be restored to functionality without major investments:

• 🔧 Shaft jamming. If the motor does not start, but the windings are intact, try turning the shaft by hand (through the flywheel). Sometimes adding oil (5W30 for compressors) through the service port helps.
• 🔥 Burnt relay contacts. Clean them with sandpaper or replace the relay (the part costs 300–800 rubles).
• ⚡ Interturn short circuit at an early stage. If the winding resistance is on the verge of normal (for example, C-S = 18 Ohm instead of 20), the compressor can last another 1-2 years with careful operation.
• 🛠️ Wear of shock absorbers. If the motor vibrates and knocks, replace the rubber dampers (cost 100–200 rubles per set).

For refrigerators Atlant and Stinol with compressors Danfoss or Secop often helps oil change. Signs that it’s time to change the oil:

• The compressor heats up more than usual.
• During operation, extraneous noises are heard (grinding, knocking).
• Traces of oil are visible on the tubes (dark spots).

Oil change procedure:

1. Pump out the freon (a vacuum pump is required).
2. Drain the old oil through the service port.
3. Fill new oil (POE for freon R134a or mineral for R600a).
4. Fill the system with freon (only with a manometric manifold!).

⚠️ Attention: Changing oil and freon requires special equipment and skills. Incorrect filling can damage the compressor.

FAQ: Answers to frequently asked questions

Is it possible to check the compressor without removing it from the refrigerator?

Yes, most checks (winding continuity, relay test, diagnostics by sound and heating) can be performed without dismantling. You only need to remove the compressor to change the oil or repair valves.

What multimeter is needed for testing?

Any digital multimeter with resistance measurement modes (up to 200 Ohms) and For example, DT-830B or Mastech MY64. The main thing is that the device shows exact values, not rounded ones.

How much does it cost to replace a compressor during service?

The cost depends on the model of the refrigerator and the type of compressor:

• Linear compressor (for example, for Atlant): 4000–7000 rubles with work.
• Inverter compressor (for Samsung, LG): 8000–15000 rubles.
• Compressor for two-chamber models: 6,000–10,000 rubles.

The price includes work, a new compressor, freon refilling and testing.

What to do if the compressor works, but the refrigerator does not freeze?

There may be reasons as follows (in order of checking):

1. Freon leak (refill required).
2. Clogged capillary tube (needs cleaning or replacement).
3. Malfunction of the thermostat or control board.
4. The compressor is worn out (does not create the required pressure).

You can only check the thermostat yourself (close the contacts). Other problems require diagnosis by a specialist.

How to extend the life of a compressor?

To make the motor last longer:

• 🧊 Defrost the refrigerator every 6 months (even if it has No Frost).
• 🔌 Use a voltage stabilizer (compressors are sensitive to jumps).
• 🌡️ Do not place the refrigerator next to the stove or radiator.
• 🚪 Do not keep the door open for more than 1-2 minutes.
• 🛠️ Once a year, clean the condenser (grid at the back) from dust.