LG Refrigerator LFX31945ST - Another LG Compressor thread

[Penfold]

Model Number

LFX31945ST

Brand

LG

Age

6-10 years

I have a LFX31945ST french door LG unit with the linear compressor. MAnufactured date of 2013, so after reading threads on here, I realise I am lucky it has been trouble free to date.

Yesterday. fridge and freezer were no longer at temp.

No icing on condenser coils, though temperature seems to be the same as ambient (using an IR temp gun), but not sure if compressor was running long enough.
Running through the test buttons on the PCB showed that the condenser fan and compressor were running, as were the two evaporator fans in the fridge and freezer compartments.

I read about checking the voltage from CON201 to the compressor, but the internet seems confused as to what figures I should see. After 30 seconds or so, it was at 120V which some seem to say is not enough and others say is fine. Thoughts?

Also, when in test button 2, the display at the front reads 22 22. Is that a fault code, or just simply a notice that it is in test 2?

 

[Jake]

Here's the service manual for your model: https://drive.google.com/file/d/1HzgNvfg0HjZN-pnZHtGrjFKgRpFW8LOm/view?usp=sharing

COMPRESSOR TROUBLESHOOTING is on Pages 67-79.

Here's the main control board for your model which has CON201 on it:

LG CSP30021077 Svc Pcb Assembly,onboarding (AP6978835) - AppliancePartsPros.com

Svc pcb assembly,onboarding CSP30021077 / AP6978835 made by LG

click.linksynergy.com

Let us know what you find.

Jake

 

[Penfold]

Thanks, that was very helpful.
Although the manual says to measure V between POWER and COMM but the diagram shows it being measured between PWR and CAP, which didn't make sense, so all my readings were between Power & COMM.

Results:
Power off - remove molex and attach leads. Power on and within about 2 minutes the V had risen to 120V and after about 15 mins it was at 127V.

Pressed Test Mode 1 and the voltages didn't change.

No blinking LEDs, so I did "Check C" and at Point A, measured 8 ohms between power and COMM and OL between Power and Ground.

Couldn't detect a temperature difference between the condenser coils and ambient.

 

[Jake]

So the compressor is running? Is the compressor running HOT? Put your hand on the top of it and see if its super hot.

Jake

 

[Penfold]

It feels/sounds like it is running and is warm, but not so hot I can't put my hand on it. It was measuring around 95F in a 75F ambient

 

[Jake]

Ok, then it sounds like a sealed system problem. Check your owners manual warranty, some models have up to a 10 year warranty on the compressor/sealed system.

The sealed system consists of the compressor, condenser, evaporator, heat exchanger, filter/drier and refrigerant. Common problems with a sealed system are bad compressors, refrigerant leaks, and system restrictions.

Jake