LG model LFC21770ST not cooling - low compressor power

[Pauli]

I have an LG refrigerator model LFC21700ST which has side by side at top and freezer on bottom - that is not cooling either in the refrigerator or freezer. Prior to this water leaked on the floor fairly frequently and ice sheets were deposited in the bottom of the freezer. A week ago it stopped cooling but has power and lights and the compressor gets warm but not overly warm – fans also run and go off when doors are open. One click is heard just before the compressor starts and this seems to come from the main board. I have done a number of things so far and there has been no improvement:

1. Changed the main board – I had one already and thought this would rule this outlines

2. Changed the thermistor w/ fuse

3. Changed the start relay and overload – but the old one is actually good – and compressor did not start with new start relay and overload - both

    start relays had similar continuities and both capacitors with within tolerances.

4 Checked the heat coil continuity which is ok – and no error code during test mode

5. Examined evap coils in freezer as far as I can tell - ok

6. Cleaned the drain from freezer which had trash in it

7. Cleaned compressor condenser coils

8. Checked compressor for short – ok

9. Checked continuity of compressor pins – ok – I think 6,6,12 roughly – one may have been a little lower than the other rather than 6,6

10. Checked receptacle and plug - ok

11. Checked lower wires between compressor and plug to wires running to main board – ok

12 Checked continuity from hot spade of plug to hot connector on plug of harness running from main board N pin to capacitor on compressor start relay

13. Checked continuity from hot (and neutral) spade on plug to black wire ( that runs next to blue wire) running from main board L pin for start relay

- here there was no continuity (OL) and I did not know if this actually ran from the hot side or neutral of the plug but I am guessing hot but there

was no continuity on either anyway -should there be? Or is there some switch that is open until a close is called for or vice versa?

14. The amp draw on both blue line (N to capacitor) and black line (L to PTC) is 0.5 A – initially 0.7-.8 then drops to around 0.5A

and stays as long as it is plugged in. There is one click at the main panel just before the compressor turns on and one as it turns

off otherwise runs quietly and it gets gently warm and the vibrations can be felt - seems like maybe not enough power to compressor(?)

15. Ran tests as indicated on back of refrigerator and got no error codes.

16. I did not check for compressor run from isolated plug because I do not have one and was not sure how to do it safely

Any ideas? Can it be a damaged black wire in the upper harness to the main board limiting power input to compressor? Can it be the compressor,  or another related part interfering with the working of the compressor? Also I was told that low amp draw if everything else is normal may indicate low coolant level, is this true (even if not necessarily in this case?) I do not  understand the necessary connections between these components and their internal workings well enough to draw any reliable conclusions yet.

Thanks for any help anyone is able to offer.

 

Pauli

 

[Koi Guy]

Good examination. Sounds to me like you may have a sealed system issue- possibly low refrigerant (most likely) or restriction (very unlikey but does happen occassionalyl. Most often I see that the evaporator coil is the failed component. 

I would put a piercing valve on and see what the pressure is. 

[Pauli]

 

 

Thanks Koi Guy, I appreciate the quick reply especially since my refrigerator has been on vacation for a week now.  I will check your suggestions out.