Help with LG split...its HOT here and it wont work

[DucatiboyStu]

I have an LG LST244V-4 inverter single head split system, 2.5hp ( from memory ) and about 4yrs old

My problem is that when you start it from the remote, it does its start up phase, I get the LED's either side of the temp lighting up in succesion ( these indicate the % of full power the comp/inverter is running), after a minute, the LED's go off, the outside fan stops blowing and it will sit there blowing air inside, then after a few more minutes it turns itself off, and the power LED in the head unit flashes 6 times. There are no other LED's or fault codes...I then have to reset it at the switch board.

I have cleaned out filters, plasma unit etc, but it made no difference.

Sometimes it will work for 5, maybe even 10 minutes blowing cold air, then its starts to shut down.

I have noticed that the higher the outside temp, the quicker it stops. We had few 43*c days and it just decided it wasnt even going to try, but at night, sometimes it will go for 10 mins..

It has worked well up untill now, i am thinking there maybe a sensor failing in it....

Anyone got any ideas

Cheers

Stu

[back2space]

I have an LG LST244V-4 inverter single head split system, 2.5hp ( from memory ) and about 4yrs old

My problem is that when you start it from the remote, it does its start up phase, I get the LED's either side of the temp lighting up in succesion ( these indicate the % of full power the comp/inverter is running), after a minute, the LED's go off, the outside fan stops blowing and it will sit there blowing air inside, then after a few more minutes it turns itself off, and the power LED in the head unit flashes 6 times. There are no other LED's or fault codes...I then have to reset it at the switch board.

I have cleaned out filters, plasma unit etc, but it made no difference.

Sometimes it will work for 5, maybe even 10 minutes blowing cold air, then its starts to shut down.

I have noticed that the higher the outside temp, the quicker it stops. We had few 43*c days and it just decided it wasnt even going to try, but at night, sometimes it will go for 10 mins..

It has worked well up untill now, i am thinking there maybe a sensor failing in it....

Anyone got any ideas

Cheers

Stu

http://mylg.co.uk/data%20for%20site/RAC%20Fault%20Codes%202007.pdf

Here are the fault codes:

6 flashes indicates overcurrent at inverter.

Your going to need an engineer to look at it if it doesnt reset itself after you reset.

[DucatiboyStu]

Hmmmm

OK, does anyone have a CCT/block diagram of the testing point. I do have the ability to test for motor winding resistance and voltages

Looks like the old Fluke is going to see some action again

Thanks in advance --- as I slowly melt into the floor :(

[back2space]

That is something I cant help on, sorry.

[fridge doctor]

Testing the compressor motor will not be conclusive. (Incidentally the motor is treated as 3 phase). If there was a problem with the compressor it wouldn't run, even for short periods. Testing the inverter board is a better option, but you will require more than a 'fluke' for that job. Sorry, but BACK2SPACE is correct. You definitely need a competent technician.

[DucatiboyStu]

Ok.

Compressor does run, and does push out cold air, the external pipes do show serious signs of condensation at the out door unit, and a "hand feel" indicates that it is pumping cold gas...i even get cold air inside, but only for a brief period, so I know that the compressor is doing its job at a basic level, I just dont know why it is shutting down....

But as Back2space has indicated, I may need a tech..

One thing does interest me, as an "inverter" , do they run a DC motor or a variable freq AC motor...

I am a comms tech ( Radio, telephony, data, DC systems, Gen Sets ) I am used to various methods

Cheers
Stu

[paul_h]

They invert to DC, then they pulse DC to run as AC.
Some companies make a pure DC inverter with a DC motor, but the standard and old way is running it as an AC motor.

Make sure the condenser fan is working, from your description, it could be something as simple as the fan motor capacitor, as they use a standard AC fan. And capacitors failing on LGs is very common.

[DucatiboyStu]

Fan motor works fine

As far as the Inverter/comp, I can hear the change in pitch/freq as the it starts to work, and runs ( on the outside unit ) it usually does this, and normally did..



Cheers

Stu

[VRVIII]

They invert to DC, then they pulse DC to run as AC.
Some companies make a pure DC inverter with a DC motor, but the standard and old way is running it as an AC motor.

Make sure the condenser fan is working, from your description, it could be something as simple as the fan motor capacitor, as they use a standard AC fan. And capacitors failing on LGs is very common.
Hi Paul,


DC Inverter usually relates to digitally controlled inverter not direct current.

[nike123]

http://i45.tinypic.com/zvaiwk.jpg
.............................

[ajr]

If it runs for a short period of time, and teh fan motor is ok, check for gas charge it may be cutting out on discharge temp sensor especially if the ambient temp is hot.

[rude]

Id say its the pc board, but i could be wrong.

2ndly the unit should still be under warranty if its 4 years old. Call lg tell them to come out.

[paul_h]

2ndly the unit should still be under warranty if its 4 years old. Call lg tell them to come out.
Good point.
vrvIII I may be behind the times, but what I was referencing is what nike123 posted, which is a at least 7 year old fujitsu information.
There is normal DC inverter compressors, like toshiba for example.
Then there is digital systems, here they call them digital scrolls, not an inverter.
There's inverters, DC inverters, and then digital, all different.
But as Rude pointed out, a/cs down here have a 5 yr warranty. So of course with me no longer being a warranty repairer I'm at the worst 5 yrs behind, and at best a couple of years behind.
Most installers down here are even further behind or clueless, as installers don't have to support their installs, separate manufacturer appointed agents handle all warranty breakdowns for those five years. I worked for one for a while, and that's what I based my knowledge on, ie fujitsu diagrams like nike123 posted, plus some info from toshiba, hitachi.
Daikin is the only brand here that is installer supported for the 5 yr warranty period, so that's the only brand I have no clue on, and post questions here about :D