Help with a dreaded LG unit..

[marc5180]

Hi Guys,
Been called to a fault today on an LG Split Unit: wall unit I haven't got the model number. Its about 2 years old. An Engineer got called to a fault and diognosed a faulty compressor. A new compressor was ordered and fitted Saturday morning but couldn't find the breaker to turn it back on so I was sent there this morning however when I turned the breaker on and got the unit up and running it trippd out straight away as soon as the compressor attempted to start. I checked the wiring of the single phase compressor all was fine, this is a very basic unit and consists only of a compassitor which feeds the fan and compressor a crank case heating and a reversing valve. I have checked all of these with an electrician and all of these seem to point to the compressor although this was only fitted on Sat. I have taken the start, run and common terminals off the compressor and started the unit up and everything seems to work and the breaker doesn't go off. Although when I check the indoor unit on the controller its flashing P0 and nothing is blowing out of the indoor unit.
Any help would be appreciated.
Cheers

[Brian_UK]

It is possible to get a faulty compressor from new, but unlikely.

Was the compressor capacitor changed at the same time as the compressor?

SIlly question but are the compressor terminals the same as the old one? Are they connectly correctly?

Is the circuit breaker damaged ?

[adams?]

always worth changing the contactor with a new comp as this may have caused your fault in the first place xxx

[Brian_UK]

Good point Adams, but knowing LG.........

[adams?]

he he, equally valid. push it off the wall and blame the wind! (joking)

[marc5180]

sorry about the double post i got my girlfriend to write it whilst i was at work and i got home and tried to edit the spelling mistakes she made but i ended up making a double post instead . The capacitor wasnt changed at the same time although i went to change the capacitor today but it wasnt the right one that i had been sent so the electrician checked the capacitor and said it was ok. the wires on the terminals are exactly the same. there isnt a contactor for the fan or compressor they just go onto a terminal block then onto the capacitor, they are very very basic. The electrician suggested that it could be a faulty breaker but he seems to think its a problem with the compressor as do i. still unsure what P0 means on the controller though. Also on the interconnectin wiring should there be voltage or not on LG units because on this there isnt any voltage

[2cool4u]

i second adams,push it off a cliff....i've had numerous problems with lg.compressors delivered wrong to site,others that look like they've been mauled by the fork lift driver,rubber bungs missing!!!.sorry not much help,but i'm still seeking therapy for comp changes that were doomed from the start

[ukcragrat]

Hi there, first post here so bear with me guys, I know you said the comp is new, but it might be worth checking the the windings aren't down to earth, not being funny here but if you weren't to sure how to check this, just remove the wires from comp and with a continuity tester go from each terminal on the comp and onto a good earth connection, if you have continuity then the windings are down to earth, so comp u/s, also the comp could be seized mechanicaly, can't really test this that easy, but if you can run the unit up at all with the comp conntected, try ready how many amp's it's pulling before the breaker trips, should have the amp reading some where on the comp so you can get an idea what it should pull. Didn't mean to sound patronising but thought some of it might be some help. Good luck. :-)

[marc5180]

Iv checked the windings down to earth and they are ok, i tried checking the amps but as soon as the compressor goes to start the breaker blows so cant really get a good reading from my amp reader

[kiwireeferman]

Has LG sent a compressor meant for an inverter machine? Three phase, 1 ohm resistance between windings.

[kevin090972]

wat is the mcb rating? 20amp or more? despite a running amp of ~5.8amp for a 12kBTU compressor and ~4.4amp for a 9Kbtu compressor, their starting amp may easily exceed 10amp, so make sure ur mcb is in order. Secondly, please check ur starting capacitor, a 25uf for a 9Kbtu and 30uF for a 12Kbtu and ~40uF fOR a 18KBtu ac. A faulty starting capacitor WILL trip ur mcb, is the compressor really spoilt in the first place? Is it tripping the mcb or the ELCB, if its the elcb, its earth leak, could be contactor problem.

[marc5180]

thanks for all of your replys. We decided to change the breaker today as a last resort and guess what? It worked!!

[adams?]

glad you resolved it......expensive though?!

[Brian_UK]

Glad that you have it sorted now Marc.

Change of tack....

Welcome to a new member ukcragrat and the first post from lurker kiwireeferman.

Welcome guys

[momo]

It could be misfortune on the new compressor, or try having the circuit breaker changed: I have had CBs go "weak and hyper-sensitive" after repeated cut outs or people using them as switches or due to over-current faults.
Keeping to regulations and good practice you should replace it with an identical one, OR you could check the rated amperage and curve <watch cable gauge etc>. and use a beefier breaker.
(We assume here you are referring to current protection or is it an Earth Leakage Breaker thats cutting out?)

[markj]

Hi, Just a thought have you checked the supply breaker type as you prob know it should be a type C or D with a rating of 16,20 or 32 amps depending on the unit size. It's sometimes possible that when the compressor failed last time it's damaged the MCB, it will still work but sometimes they can then be over sensitive there after to high start currents and trip out

Mark

[NH3LVR]

I have seen that the opinion of LG equipment is not the highest.
Does this include their home appliances as well?
I am asking because Home Depot is now selling them here in the US.

[hendrag]

hi this sounds like a wierd one, a few questions?

what is the model number?, does the old compressor look like the new one ? if not its probably wrong if it does look the same and have the same connections its probably perfect. What are the winding resistances ?

if you are still strugling with it call me on 01753876776 ask for Graham i run LGuk tech support i will sort it out for you

good luck

hendrag

[Slim R410a]

The problem was a faulty breaker wasn't it?