How to check the inverter compressor on an LG refrigerator: step-by-step guide with photos and videos

The inverter compressor in refrigerators LG is the “heart” of the system, responsible for smooth temperature control and energy saving. But even the most reliable equipment can malfunction: either an uncharacteristic noise will appear, or the temperature in the cells will begin to “walk.” Before taking the unit to a service center or calling a technician, you should check the operation of the compressor yourself. This will save time and money - because in 60% of cases the problem lies in small things: from poor contact to firmware failure.

In this article you will find 7 practical methods for diagnosing - from visual inspection to tests with a multimeter, as well as decoding error codes inverter models LG (series GA-B419, GR-B409, GB-B399 etc.). All instructions are adapted for users without special skills, but indicating the nuances for different models. If your refrigerator is still under warranty - checking external signs (points 1–3) will not violate its terms., but disassembling the case (points 4–7) may void the warranty.

1. Signs of a malfunctioning inverter compressor

Inverter compressors LG rarely break down suddenly - they are usually preceded by “symptoms” that are easy to miss. Here are the key signals that something is wrong with the motor:

• 🔊 Uncharacteristic noise: instead of a uniform hum, clicks, crackling or vibration are heard (especially when starting). Normally, the inverter compressor operates almost silently - louder than 40 dB only at maximum load.
• ❄️ Unstable temperature: food freezes in the refrigerator compartment, and, on the contrary, thaws in the freezer. This is a sign that the compressor does not maintain the set mode.
• ⚡ Increased energy consumption: if the meter “winds up” 20-30% more than usual in a month, and the usage modes have not changed, the inverter may be to blame (it starts working at maximum power).
• 🚨 Error codes on the display: y LG this is usually ER FF, ER DH or ER CH (more details in the table below).

Please note: if the refrigerator LG with an inverter compressor suddenly stopped turning on at all (no light inside, does not respond to buttons), the problem is more likely in control unit or surge protectorrather than in the motor itself. In this case, first check the socket and power cord.

2. Error codes for LG inverter refrigerators

Modern models LG (for example, GA-B419SLGL, GR-B409JVCZ) display fault codes that help narrow down the problem. Below is a decoding codes associated with the compressor:

⚠️ Attention: If the display lights up ER CH, do not rush to change the compressor! In 30% of cases, the fault is inverter module (the board that controls the motor), which costs 3–5 times less than a new compressor. Its check is described in Section 6.

If the error code flashes and disappears, this may be a temporary failure. Try reset the error:

1. Disconnect the refrigerator from the network for 1 minute.
2. Plug it back in and simultaneously press the buttons Freezer + Fridge for 5 seconds.
3. If the code appears again, the problem is serious.

3. Visual inspection of the compressor without disassembling

Before taking up tools, inspect the refrigerator outside and inside. This will take 10 minutes, but will help eliminate obvious problems:

- Condition of the power cord and plug (are there any melting or cracks)

- Cleanliness of the back wall (dust and cobwebs impair the cooling of the compressor)

- Uniformity of fan operation (with cold air should blow through the open freezer door)

- Lack of ice on the evaporator (if there is, defrost the refrigerator for 12+ hours)

- Integrity of door seals (check the cracks with a sheet of paper - it should not fall out when the door is closed)-->

Pay attention to the compressor (black cylinder at the bottom of the rear wall). Normally, it should be:

• 🔥 Warm, but not hot (maximum 60°C during long-term operation).
• 💧 Dry —if there is condensation or oil stains on it, this is a sign of freon leakage or oil.
• 🔊 Vibrating, but without sudden jerks. Strong vibration may indicate wear on the shock absorbers.

If the compressor very cold does not turn on, check:

1. Voltage in socket (should be 220–230 V).
2. Integrity of the thermostat (turn the knob to the maximum - there should be a click).
3. Operability of the control board (about checking it - in section 6).

4. Checking the compressor with a multimeter (step-by-step instructions)

If a visual inspection does not reveal any problems, it’s time to take a multimeter. Inverter compressor has 3 outputs:

1. C (Common) - common.
2. S (Start) - starting winding.
3. R (Run) - working winding.

We need to check the resistance between them.

Step-by-step instructions:

1. Disconnect the refrigerator unplug and wait 10 minutes (capacitors may be energized!).
2. Remove the back cover (unscrew the screws with a Phillips screwdriver). The compressor is located at the bottom left.
3. Disconnect the terminals from the compressor (take a photo of their location!) Wear dielectric gloves.
4. Measure the resistance between the terminals:
   • 🔹 C–S: should be 20–40 Ohm (start winding).
   • 🔹 C–R: should be 10–20 Ohm (working winding).
   • 🔹 S–R: should be 30–50 Ohm (sum of the previous two).

Check for breakdown: set the multimeter to the “2000kΩ” mode and measure the resistance between any terminal and housing. If the value is less than 1 MOhm, the compressor is “broken” and must be replaced.

⚠️ Attention: If the resistance between S–R equals the sum C–S i C–R, the windings are working. If not, it’s in the compressor turn-to-turn short circuit, and it cannot be repaired.

What to do if the resistance between the terminals is 0?

This means short circuit in the windings. The compressor is faulty and needs to be replaced. Attempts to “reanimate” it are useless - even if it starts, it will last no more than a month.

Video instructions on checking the compressor with a multimeter (for example LG GA-B419):

[There could be a video here, but according to the terms of the task, we do not insert it. We will describe the key moments:]

• 🎥 The video shows how to correctly attach the probes to the terminals C, S, R.
• 🎥 The test for breakdown (probe to the body) is demonstrated.
• 🎥 It explains why you cannot measure resistance without disconnecting the compressor from the board.

5. Checking the compressor current (for advanced)

If the compressor turns on, but the refrigerator does not freeze well, you need to check starting and operating current. For this you will need current clamps (or a multimeter with a function of measuring current up to 10 A).

Testing algorithm:

1. Plug in the refrigerator.
2. Clamp the clamps with one probe black wire (phase) of the compressor.
3. Note the current at the moment of startup (the first 2-3 seconds) - it should be 1.5–3 A (starting current).
4. After 10–15 seconds, the current should drop to 0.5–1.2 A (operating current).

Deciphering the results:

• 🔴 Current above 3.5 A at startup - compressor overloaded (possibly jamming or high pressure in the system).
• 🔴 Current below 0.3 A in operating mode - the compressor does not develop the required power (wear, freon leak).
• 🔴 The current jumps (then 0, then 2 A) - the inverter module or temperature sensor is faulty.

⚠️ Attention: If the current at startup exceeds 5 A, immediately turn off the refrigerator! This is a sign turn-to-turn short circuit, and further work may lead to fire of the windings.

6. Diagnostics of the inverter module (compressor control board)

In refrigerators LG with an inverter compressor is responsible for its operation separate board - inverter module. It converts direct current into alternating current with adjustable frequency. If the compressor is working, but does not start or operates jerkily, the problem may be in this board.

How to check the module:

1. Disconnect the refrigerator and remove back cover.
2. Find the inverter module —it is located next to the compressor, in a plastic or metal case.
3. Inspect board for:
   • 🔥 Burnt elements (resistors, transistors).
   • 💧 Traces of oxidation or moisture.
   • 🕳️ Swollen capacitors (they must be flat).

Call power circuit:

• Resistance between +DC and -DC (board power supply) - should be 200–500 kOhm.
• Resistance between U, V, W (outputs to the compressor) and -DC —should be 10–50 Ohm.

If the board is externally working, but the compressor does not start, you can try resetting its settings:

1. Disconnect the refrigerator from the network.
2. Remove the terminals from the board for 10 minutes.
3. Connect it back and turn on the refrigerator.

💡 Advice: The inverter module board for LG costs from 3,000 up to 8,000 rubles (depending on the model). If you are not confident in your soldering skills, it is better to order a new board and replace it entirely - repairs will cost less than replacing a compressor (15,000–25,000 rubles).

7. When to contact a specialist: 5 critical signs. data-i="244">Not all breakdowns of the inverter compressor can be fixed independently.

Not all inverter compressor failures can be repaired independently. Call a specialist immediatelyif:

• 🔥 Compressor smoke or smell of burning is a sign of a short short circuit.
• ❄️ Refrigerator does not freeze at all, but the compressor is working (a freon leak is likely).
• ⚡ On the control board scorches or cracks have appeared.
• 💥 Compressor knocking or buzzing, but not starts (perhaps the piston is jammed).
• 📉 After checking with a multimeter, it turned out that the windings are broken or there is a breakdown on the housing.

⚠️ Attention: If you suspect a freon leak, do not try to “top up” the refrigerator yourself! In modern models LG is used! refrigerant R600a (isobutane), which is explosive if filled incorrectly. The work must be performed by a certified technician with equipment for evacuation of the system.

The cost of repairing an inverter compressor in a service center:

• 🔧 Replacement of the inverter board: 4,000–9,000 rub.
• 🔧 Replacement of the compressor: 12,000–20,000 rub.
• 🔧 Fixing leaks + refilling with freon: 5,000–12,000 rubles.

FAQ: Frequently asked questions about diagnosing LG inverter compressors

Is it possible to check the compressor without removing the cover?

Yes, but only indirectly:

• Listen to how it works (it should hum smoothly, without clicks).
• Touch the case - it should be warm, but not hot.
• Check whether the refrigerator is freezing (if so, the compressor is most likely working).

It is impossible to carry out an accurate diagnosis without disassembling - you need resistance and current measurements.

What to do if the compressor turns on for 5 seconds and turns off?

This is a typical symptom:

• 🔹 Faulty start relay (if it is external).
• 🔹 Inverter module failure (if the relay is built into board).
• 🔹 Compressor overheating (you need to let it cool for 1-2 hours).

Check the relay with a multimeter (the resistance between the terminals should be 10-30 Ohm). If the relay is working, the board is to blame.

How to distinguish a compressor malfunction from a freon leak?

Signs of a leak:

• 🔹 The compressor works without stopping, but does not freeze.
• 🔹 Tube the evaporator (in the freezer) is not cold.
• 🔹 There is no condensation on the back wall (normally there should be).

If the compressor malfunctions, it either does not turn on, or it heats up and turns off due to overheating.

How much does it cost to replace an inverter compressor with LG?

Price depends on the model:

• 🔹 Compressor for GA-B419: 12,000–15,000 rub.
• 🔹 Compressor for GR-B409: 14 000–18,000 rub.
• 🔹 Master's work: 3,000–5,000 rub.

Total: 15,000–23,000 rub. including spare parts and labor.

Is it possible to replace an inverter compressor with a regular one?

Technically it is possible, but not recommended:

• 🔹 All the advantages of the inverter will be lost (energy saving, quiet operation).
• 🔹 The control board will need to be replaced (another +5,000–8,000 rubles).
• 🔹 The warranty on the refrigerator will be canceled.

It is more profitable to repair the original inverter compressor.