How to Test Your Compressor Motor and Its Overload Device on an LG refrigerator.

Written By: Bill Gilbert
  • Comments: 5
How to Test Your Compressor Motor and Its Overload Device on an LG refrigerator.

Difficulty

Moderate

Steps

8

Time Required

30 - 35 minutes

Introduction

Use this guide to test the linear compressor motor and its attached overload device for your LG refrigerator.

This guide will work for most LG refrigerators with linear compressors. This guide is written with an LG model LFX25973 refrigerator. If you have a different model, you may encounter some minor disassembly differences, but the overall repair process will be the same.

The compressor is the heart of your refrigerator, and if it fails or can't start, your refrigerator is useless. Without the compressor, the refrigerant can't circulate and can't function to cool the interior of the fridge.

Symptoms of such failure include no compressor sound from the fridge and increasing temperature inside the fridge. Sometimes, there may be repeated clicking noises coming from the lower part of the fridge.

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    • Unplug your refrigerator before you begin your repair.

    • If you are testing or repairing the following items, you may also need to shut off and disconnect the water supply:

    • Condenser fan motor

    • Compressor motor and thermal overload device

    • Water supply valve assembly

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    • Use a Phillips screwdriver to remove the screws securing the condenser cover to the rear of the refrigerator.

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    • Tilt the top edge of the condenser cover toward you.

    • Lift and remove the condenser cover.

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    • Squeeze and pull down the compressor connector to disconnect it.

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    • You should wear gloves to protect your hands from the sharp edges in this area

    • Use your multimeter to measure the resistance between the two pins on the connector.

    • Acceptable values are between 7 and 14 ohms

    • This test checks both the compressor winding and thermal overload device.

    • If you get an open reading, it could be either the motor or the thermal overload device. Follow the next steps to continue diagnosing.

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    • Use a Phillips screwdriver to remove the screw(s) securing the connector cover to the compressor.

    • Slide the connector cover off of the compressor.

    • Don't try to fully remove the connector cover as it is still connected to the compressor.

    • The thermal overload device is located in the cover and is wired in series with the compressor.

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    • Use a small flathead screwdriver to pry the power connector off of the compressor.

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    • Use your multimeter to check the resistance between the bottom and top left pins.

    • The correct resistance value is 7.2-9.2Ω for a FLA075LANA or FLB075LANA compressor; other models show 6-8Ω.

    • If you were reading an open circuit in the first test, and now you get good resistance readings for the compressor, your overload device is faulty; replace it.

    I measure about 9.2 ohms on my FLA075LANA compressor yet, I get a "six blink" error code indicating an over current. I've found that the voltage (with a true RMS meter) at the compressor tends to hang around 130v with about .72 amps of current (via clamp on meter, so not sure of the accuracy) but at some point the voltage slowly climbs and so does the current. The highest I've measured is 200V and 1.5A. It's not clear to me if there is a problem in the sealed system or if the control board is faulty. The complaint is that both the fridge and freezer are warmer than they should be. Any suggestions?

    Gawandy -

    Those readings sound appropriate since I believe the rated power of the compressor is around 300 watts if I recall correctly. I would try first confirming your temperature settings, then also make sure that you are fully defrosted. One usual result of a iced over evaporator is excessively warm temperatures. My apologies, but I'm not very familiar off the top of my head with the 6 blink error code. Are you talking about the control board LED blink codes? What is the model number of your fridge? You might also want to check the condition of your compressor run capacitor, but the readings you are getting make me wonder if the control board is defective, because the readings sound okay. I'm out of the office, so I don't have service manual information at my fingertips.

    Bill Gilbert -

    If the overload and the compressor winding tests are good , what next?

    Andy Miller -

Conclusion

To reassemble your device, follow these instructions in reverse order.

Take your e-waste to an R2 or e-Stewards certified recycler.

Repair didn’t go as planned? Try some basic troubleshooting, or ask our  Answers community for help.

Author

Bill Gilbert

Member since: 30/06/22

34697 Reputation

2 comments

If the overload and the compressor tests are good. What next?

Andy Miller -

It depends on what you have already done. Did you test the compressor because it was refusing to run? Have you also checked the run capacitor? It is located near the control board. If it fails, the compressor will not run. To try to help more, I'd need to know more of what the problem is.

Bill Gilbert -