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Author Topic: Need help with a LG LinearCompressor  (Read 6728 times)

Offline re5513

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  • Member Since: Sep 2020
  • Posts: 9
Re: Need help with a LG LinearCompressor
« Reply #20 on: September 24, 2020, 03:00:51 PM »

^ I meant to say that the INVERTER appears to be good (output at the compressor is >200V RMS).  It also appears to me that the compressor is running, albeit very quietly when the Main PCB Test Mode 1 is selected.

Here is another look at the voltage at the pins of the Compressor (compressor not attached, just the voltage at the connector).  When the connector is attached, the compressor appears to run.

Offline re5513

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  • Member Since: Sep 2020
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Re: Need help with a LG LinearCompressor
« Reply #21 on: September 25, 2020, 07:13:21 PM »
More follow up.  I made up a jig to safely connect the FC75LANE compressor to 120v RMS line power.  It hums quietly; however I note the following.
     1. The high pressure output does not get warm and the low pressure input does not get cold
     2. The compressor draws a whopping 0.5A when connected this way.

With the low amp reading I believe there are two possibilities.
     A. There is a seal inside the FC75LANE compressor that has failed and it is not able to achieve any kind of compression. or
     B. It is low on freon.

I would expect it to make more noise, perhaps metallic noises if it a seal had failed so next up I'll test the freon level.

Thanks again for the hint to connect it directly to line power, that was a very useful diagnostic.

Cheers,
RE5513

Offline houptee

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  • Member Since: Jan 2010
  • Posts: 125
Re: Need help with a LG LinearCompressor
« Reply #22 on: October 20, 2020, 09:36:14 AM »
What did you find when you tapped the system?

Offline re5513

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  • Member Since: Sep 2020
  • Posts: 9
Re: Need help with a LG LinearCompressor
« Reply #23 on: October 20, 2020, 09:53:49 AM »
The low side was about 60 psi and stable, compressor running or not running.

I pulled the compressor and noted on the bench that it had no output on the high pressure side indicative of valve failure.

I found a good deal on a NIB compressor which I installed in the unit and also put in a new inverter board.  After nitrogen fill and then deep vacuum, I filled it with the specified 4.9oz of R-134a and the fridge appeared to be back in business.

I got a call about 3 days later indicating the fridge was no longer cooling.  I looked at it again over the weekend and found a leaking schrader valve on the low pressure service port on the new compressor.  That was frustrating.  Replaced schrader valve  It appears the new compressor now may have failed.  High pressure is a steady 95 psi, low pressure is a vacuum, no cooling.  Thus, tis a puzzlement at this point.

Offline tcarmen

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  • Member Since: Dec 2018
  • Posts: 129
Re: Need help with a LG LinearCompressor
« Reply #24 on: October 20, 2020, 02:10:12 PM »
If you didn't change the dryer and flush the high side, it has probably failed again. The compressors often leave a bunch of contamination in the system when they fail.