LG Problem

[Kirky]

Hi guys hows all

Got a problem with a LG split. Customer reporting indoor unit blowing hot air. The unit is cooling a server room in conjunction with a mitsi split which has just been upgraded from 6 to 10KW. The room temp is 23 degC and both units are set a 20degC. Dropped setpoint on LG in order to give it something to do. The condenser fan runs but the compressor does not even attempt to start. Outdoor unit LG LS-K2460ML very basic just has power supply capacitor compressor and fan. No PCB. Seems like the compressor isnt getting a signal to start. I was thinking faulty PCB on indoor any other suggestions

[paul_h]

If mains power is sent to outdoor unit then it's a faulty compressor or capacitor.
If there is no mains voltage at the outdoor, then its a break in the cabling or faulty indoor pcb or relay.
If theres no mains voltage at the indoor terminals, that rules out a cabling fault, so it has to be relay or control PCB

[Kirky]

Cheers for getting back to me so soon. Yes I have mains voltage at the outdoor unit the condenser fan runs constantly. Its looks as if the fan motor and compressor share a 40 microfarad capacitior. The outdoor unit is so basic so i guess it can only be the capacitor or compressor but if the fan motor and compressor are sharing a capacitor which is faulty then surely the fan shouldnt run. Also if the capacitor for the compressor is faulty then it should be pulling high amps and tripping the breaker which there isnt any evidence of. Im confused I hate LG. :rolleyes:

[AbsoluteWDJ]

Cheers for getting back to me so soon. Yes I have mains voltage at the outdoor unit the condenser fan runs constantly. Its looks as if the fan motor and compressor share a 40 microfarad capacitior. The outdoor unit is so basic so i guess it can only be the capacitor or compressor but if the fan motor and compressor are sharing a capacitor which is faulty then surely the fan shouldnt run. Also if the capacitor for the compressor is faulty then it should be pulling high amps and tripping the breaker which there isnt any evidence of. Im confused I hate LG. :rolleyes:

Is there mains power to compressor start terminal? If so check to see if the compressor has any internal/external overload that has tripped.

[Kirky]

No power to compressor start terminal and I cant find a overload Im thinking towards the capacitor or the pcb there must be a relay on the pcb. cheers

[paul_h]

power would be to common, as the start and run windings go to neutral.
There would be nothing at the compressor start terminal if the compressor was out on internal overload or the start/run winding was open circuit.

[Temprite]

if the fan motor and compressor are sharing a capacitor which is faulty then surely the fan shouldnt run.

Think of them as two capacitors one for fan and one for compressor. Even if compressor side is faulty, fan side can still run.

[fridge doctor]

The LG capacitor has 3 terminals. One of them is common and the other 2 are compressor and fan respectively. If I remember correctly 'herm' - 'com' and 'fan' are embossed on the capacitor casing next to the terminals. Effectively this is two capacitors in a single casing, and either one will still work if the other fails. The fault you have is 99% certain to be failed compressor capacitor.

You can either order a 3 terminal cap from LG, or you can perform a simple by-pass. Leave the failed capacitor in circuit to take care of the condenser fan, and introduce a new cap of the correct value (you didn't say what size the unit is). The present cap will state something like "35/3uf" meaning that you need to bring in a new 35 microfarad capacitor. Just run a new cable from the spare terminal marked common on the old cap, to one side of the new capacitor. Then remove the lead marked 'fan' from the old cap and plug it to the other side of your new 35uf cap. I am sure you will find that cures the problem... good luck.

[paul_h]

I always toss them, poorly made and prone to fail. I'd rather not get a call back when the other cap fails.
I always get two replacement caps, one for compressor and one for the fan.
One problem though is generic caps only have 2 spade terminals, while OEM caps have 4 (as they use the common as a neutral terminal block for the fan, reversing valve and all sorts of other gear.
Instead of cutting off spades and fitting piggyback spades or BP connectors, you need a pack of these, female spade to two male spade piggy back connectors.
http://cgi.ebay.com.au/ws/eBayISAPI.dll?ViewItem&item=130004692564&ssPageName=STRK:MEWNX:IT
a couple of these on each of the capacitors normal double spade terminals, and you're sweet again to hook up the a/cs OEM four spades to neutral. No cutting or joining, no crimping, just plug and play.

[fridge doctor]

Fair and valid point Paul, but I have found it has always been the comp side that fails, and my choice of replacements in this part of the world, is between cheap chinese or chinese cheap. So I just replace the half that's gone rather than both. Hope all is OK with you mate.

Trevor

[Kirky]

Cheers guys ill replace the capacitor and let u know how it goes

[Kirky]

Hi guys have changed the capacitor no change compressor still wont run. Customer getting a bit peed off took a week to get the spare from LG. (Give me a daikin or mitsi any day) There is obviously something holding off the compressor. Not really up to speed with LG dont deal with them as a rule cheap tat. Anyway got to much on to worry about it units 8 years old and on a server room so its had a hard life. Time for a new one me thinks.

Cheers

[fridge doctor]

Sorry mate, trust me it was worth a try but it def looks like the compressor is seized. As you say - hard life, constant use 10 years, time to go.

[rude]

Sounds to me like your still not sure that theres power at the compressor. Are the neutral wires connected properly? Did you test the cap for its correct capacitance rating?