LG LS-L1262YL erratical behavior

[nike123]

My ex colleague called me today and asked me if I could check and repair indoor PCB for mentioned air conditioner.
He knows that I repair Fujitsu PCB-s so that is why he ask me that.
Then I ask him why he thinks that is PCB damaged.
He explain that after some time unit stop work correctly (don't produce heat and only blows cold air in heat mode, also compressor stops). After that, sometimes passes half hour, and sometimes few hours till unit starts to heat again, no matter what he do. He could not establish pattern of repetitions of this error nor find any error in parts that could explain that behavior and, he said, that he suspect that indoor unit PCB is somehow responsible for that.
Does anyone has seen similar problem whit these units and what are possible cause for that.
Also does anyone have service manual (or link to it) for that particular model. I need it to establish is this problem with PCB or is something else.
By his words, This LG don't have diagnostic signalization at display of indoor unit.

Thanks for yours kind replays.

[chillin out]

It sounds like a sensor fault.
Either the outdoor unit is falsely saying that it is iced up and wants to defrost of the air sensing probe on the indoor unit is faulty or in the wrong place.

Chillin

[nike123]

It sounds like a sensor fault.
Either the outdoor unit is falsely saying that it is iced up and wants to defrost of the air sensing probe on the indoor unit is faulty or in the wrong place.

Chillin

Do you have T/R chart for these probes, so I could check if they are OK.

[fridge doctor]

Hi,

Unfortunately I can't shed any light on the possible cause of the problem, but if I might make an observation, it would be that :

1/ If the outdoor sensor was faulty and caused the unit to go into 'defrost' mode, this would be apparent in that the compressor would be running, and the process would only take seconds rather than hours before reverting to heating.
2/ Not sure what you mean by a T/R chart, but sensors can all be checked using a multimeter. They are almost always either perfectly Ok, or open circuit. So if you get a reading of any sort you can pretty much rule it out.

Regards,

trevor

[hangman]

Im a first timer. can u tell me how to send a fn new message please. Sorry about that

[nike123]

Hi,

Unfortunately I can't shed any light on the possible cause of the problem, but if I might make an observation, it would be that :

1/ If the outdoor sensor was faulty and caused the unit to go into 'defrost' mode, this would be apparent in that the compressor would be running, and the process would only take seconds rather than hours before reverting to heating.

It depends on algorithm of processor how he will interpret values given by sensors of outdoor unit and indoor unit together.

2/ Not sure what you mean by a T/R chart, but sensors can all be checked using a multimeter. They are almost always either perfectly Ok, or open circuit. So if you get a reading of any sort you can pretty much rule it out.

Regards,

trevor

T/R mean relation between temperature and resistance.
In order to rule out thermistor as cause of malfunction, I need to know relationship of temperature and resistance of measured thermistor and his correct value given by manufacturer chart. Measuring only open circuit or some resistance which you could not compare with anything, you can't rule out that thermistor is not the cause of malfunction.
That is, at least, my approach to resolving problems.

[nike123]

Sorry, I don't understand this part "how to send a fn new message"!

[Mac1]

This may help.....

Heating mode operation

•

Operating frequency of compressor depend on the difference of the temperature

(= compressor off temp. - intake air temp.)
•

Compressor off temp. = setting temp.+3.0°C

on temp. = setting temp.
•

If compressor operates at some operation frequency, the operating frequency of compressor cannot be

changed within 30 seconds.
•

Condition of compressor turned off

- When intake air temperature reaches +3°C above the setting temperature.
•

Condition of indoor fan turned off

- While in compressor on:indoor pipe temp. < 30°C
•

While in defrost control, between the indoor and outdoor fans are turned off.

•

Compressor 2minutes delay
- After compressor off, the compressor can restart minimum 2 minutes later.

If you send an email to Airconhelpuk@lge.com I'm sure they'll be able to email you a Service Manual.

[nike123]

This may help.....

Thanks for your kind input!
Unfortunately, that job is not my concern any more, but your contribution could help someone else in the future.