LG Model Split Air Conditioning Cooling Intermittently

[zkjnxzkcuwf]

I have an LG Split Air Con System in my condo (well 2 units actually - one working well and the other intermittently) It's the standard vent unit-type attached to the wall indoors and the larger fan units outdoors.

It is blowing warm air most of the time, but the compressor comes on intermittently and blows cold air for a short period before reverting back to blowing warm air.

I've had a technician trying to repair it for days now.

The first thing he did was change the 'compressor'? Or he changed some part inside it, but it did not seem to have any effect.

After that, I noted how it was working: it was operating like this:

1) Warm air coming out.
2) Fan comes on for 10 mins,
3) Compressor starts.
4) Blows cold air for 7 minutes.
5) Fan stops and compressor stops.
6) Warm air coming out for 8 mins.
7) Fan comes on (cycle repeats itself from step 2).

The technician then came back and cleaned both inside and outside units, top to bottom with some kind of powerful compressed air cleaner.

Now, it operates in a similar fashion to the cycles described above, except now, it is warm MOST of the time, with the compressor and fan OFF most of the time, and only cold for a short while before going back to warm.

The tech is now 'guessing' that it could be a 'sensor' problem and is going to swap sensors over between my other 'working' LG air con unit to test it.

Another point to mention is that in the short time periods when it does blow cold air, it is not as cold as my other 'working' LG unit.

Many thanks for any pointers in the right direction to solve this problem.
Thanks,
Des.

Edited April 21, 2015 by zkjnxzkcuwf

[Pib]

Changing a compressor is costly...probably in the Bt7K to Bt10K (or more) for a new compressor. If your repair bill was not that high he did not change the compressor. Sounds like you really don't know what he did on the first visit. I find it strange he would do the cleaning on the second visit as he could have determined if a dirty inside and/or outside unit was the problem from the get-go.

The roughly 50% on-off cycle you described would probably only occur when not much cooling is required...like during cooler weather or having the temperature setting up around 28 to 30C. But in the current hot weather in most Thailand locations I doubt you are experiencing much cool weather during this hottest time of the year in Thailand. Mar, Apr, and May are usually the months a person experiences their highest monthly electric bills assuming they use their A/C pretty much year round (like me here in Bangkok).

Sounds like it may be time to get another repairman if he can't figure the problem out. The problem could be a wide variety of problems...compressor problem....incorrect freon level....electronic boards that control the cycling...etc. Sensors are very reliable devices but the electronic circuit board they hook to could have problems I guess. Good luck.

[zkjnxzkcuwf]

Changing a compressor is costly...probably in the Bt7K to Bt10K (or more) for a new compressor. If your repair bill was not that high he did not change the compressor. Sounds like you really don't know what he did on the first visit. I find it strange he would do the cleaning on the second visit as he could have determined if a dirty inside and/or outside unit was the problem from the get-go.

The roughly 50% on-off cycle you described would probably only occur when not much cooling is required...like during cooler weather or having the temperature setting up around 28 to 30C. But in the current hot weather in most Thailand locations I doubt you are experiencing much cool weather during this hottest time of the year in Thailand. Mar, Apr, and May are usually the months a person experiences their highest monthly electric bills assuming they use their A/C pretty much year round (like me here in Bangkok).

Sounds like it may be time to get another repairman if he can't figure the problem out. The problem could be a wide variety of problems...compressor problem....incorrect freon level....electronic boards that control the cycling...etc. Sensors are very reliable devices but the electronic circuit board they hook to could have problems I guess. Good luck.

Thanks Pib,

Initially, he took a quick look at the compressor, saw that the fan wasn't running and went out and got a replacement part (no idea what it was) which he charged 1200 baht for. After that, not much changed and the situation is as described above. He's been coming back and forward, playing about with the remote control, and then concluding each time it is working when cold air starts to come out only to find out later, when I call him that it is 'warm' again I feel sorry for the guy, as he is the handyman for this condo - I'm in BKK.

He's going to swap the sensor with my working unit tomorrow - if that doesn't work, I'll have to look around for someone more experienced I guess.

Thanks.

[Chicog]

If you are using a handyman to fix an AC instead of a trained technician, then that could be your problem right there.

I mean if he's not charging you to change it bit by bit then fine, eventually you may end up with a complete replacement.

But if he's just using trial and error maybe you should talk to someone who understands LG AC units?

This was the first link I found in Bangkok.

http://aircongenie.com/

[eyecatcher]

From what you drscribe it sounds like there is no coolant in the compressor.....leaked out? Did your man check or top up?

[zkjnxzkcuwf]

If you are using a handyman to fix an AC instead of a trained technician, then that could be your problem right there.

I mean if he's not charging you to change it bit by bit then fine, eventually you may end up with a complete replacement.

But if he's just using trial and error maybe you should talk to someone who understands LG AC units?

This was the first link I found in Bangkok.

http://aircongenie.com/

I'm going back to the Juristic Manager tomorrow in the condo office to let them know that their AC man (or handyman) has not been able to fix the problem.

Yes, you're right - he is using trial and error and doesn't seem the type to simply say 'he doesn't know' - he's not charging me anything now, and just keeps coming back to try to fix it. Time to get someone who does know to work on it.

[zkjnxzkcuwf]

From what you drscribe it sounds like there is no coolant in the compressor.....leaked out? Did your man check or top up?

First he changed a part in the compressor - I have the receipt but it's written in Thai..

Still intermittent cold and warm.

Then, he checked the coolant and topped it up.

Same problem..

Then, he used some sort of high-powered compressed air gun to clean it...

Same problem,

And then, he thought that the timer function on the remote control was causing the problem (which logically would also affect my remaining 'working' AC unit as well if it was a timer function problem) - it's just a simple remote control and the timer is off..

Same issue,

So now, he's offered to swap over the sensor with the working unit to test it.

I'm calling it a day I think at this point and will just get the office to appoint someone else to fix it...

Thanks for your reply

[Pib]

Where you say he changed a part in the compressor unit (actually it's called the condenser unit...which some people call the compressor unit since it also includes the compressor among other things...which some people call the outdoor unit which I will call it) because the outdoor unit's fan was not turning. That could have been caused by various things but a common fault is the outdoor unit's "fan run capacitor" failed or the outdoor unit's "compressor start capacitor" failed which is external to the compressor. The compressor itself is a sealed unit which can only be repair/overhauled at the factory/specialize facility...it looks something like below.

If the compressor "start" capacitor failed the compressor will not start...about all you will hear is a very brief attempt (way less than a second) of the compressor trying to start but it can't because its "start" capacitor gives it a kick-start/surge of power to get the compressor running (kinda like kick starting a motorcycle) and then after just a few seconds switching inside the outdoor unit takes the start capacitor out of the circuit as the start capacitor has done its job... plus it's not designed to be in the circuit all the time because it would fail very quickly if in the circuit the whole time (actually it would fail within a minute or so...it's only suppose to be in the circuit for a few seconds). If you've ever been in a Amorn Electronic Store like in/close to many Tesco Lotus stores you see they sell quite a few start capacitors which are about the same physical size as a small cola can and silver in color....usually going to be around 35 to 60 microfarads in capacitance size...they cost approx Bt150 at Amorn.. Such start capacitors are common on anything that uses a motor/compressor like A/Cs, washing machines, etc. In fact the 45 microfarad start capacitor on one of my York split air units failed just a few months ago....you could hear a click/grunt when the compressor tried to start but it wouldn't and only the outdoor unit's fan would be running. But when the compressor don't start that means the freon can not be circulated and compressed through the A/C system which means just warm air since your indoor unit is basically just circulating room air. Start capacitors on an outdoor unit are usually very easy and quick to replace after you gain access to the capacitor...literally just a minute or two in most cases....usually the wires are not soldered on and just use pull on/pull off connectors. Now if the compressor is "not" running when it's suppose to be, the outdoor unit fan can still be turning fooling a person into thinking the compressor is running also...but when you the compressor is indeed running you can hear that low hard-working motor sound...and of course it easy to know if the fan is working by visual means. On a properly operating unit the compressor and fan will both turn off and on together...both are running...but if one has a problem then only the other one will probably been running.

The outdoor unit's fan also has a capacitor but it's referred to as the "run" capacitor. It's a much smaller capacitor both in physical and capacitance terms and can serve as a combo start and run capacitor depending on circuit design...gives the fan motor a little kick to get it started but its main function is the slightly shift the phase of the voltage on some of the motor windings to keep the fan motor spinning....the run capacitor is always in the circuit. There will be a small run compacitor in floor/desk/ceiling fans, small pump motors, washing machines, etc. You'll also see a bunch of these sold at Amorn Stores usually for around Bt50...they are rectangular in shape, usually black in color, and about the size of a matchbox....they too are pretty easy/quick to replace but sometimes the wires are soldered on....but of course many people just cut the wires and then twist the wires back together versus using a soldering iron to remove/replace.

Where you said he used a compressor "air" gun to clean the unit. If the gun was only "blowing air" then that's going to do little to clean an A/C....it needs to be blowing pressurized "water" like at a car wash. Most A/C repairmen will use a small pressure washer to do the job. But maybe that is what you meant. Just make sure he used "liquid" to do the cleaning.

When testing the unit be sure the remote control is set to "cooling" and the lowest temperature setting to force the A/C into max cooling which will keep the compressor running 100% of the time. If the remote is set to "Auto, Dry or some other control setting" that's going to allow the unit to change the on-off cycle of the outdoor unit, the inside unit fan speed, etc. Then, if the A/C seems to be cooling properly that should help with the trouble shooting and eliminate some of the possible cooling problems.

It may be time to get another repairman because the one you have now doesn't seem to have detailed knowledge/experience on your particular A/C...and is just using a replace this or that until it hopefully works properly. Your problem could be as simple as a freon leak...then the problem becomes finding the leak and sealing it...a freon leak detector is required for that if a "small" leak...a larger leak can be found other ways....even a small leak can cause a topped-up system to lose a lot of freon just over a few days....you are then back to no cooling. But to be fair, some problems--especially intermittent problems--can sometimes be hard to find the root cause...I hate intermittent problems. Good luck.

[zkjnxzkcuwf]

Thanks Pib, and good news!

4 new technicians came along today, opened up the outside compressor and pulled out a big silver 6" capacitor array unit (looks like a big silver cylinder)- this was most likely the part that was changed by the previous tech. The new techs said that it was for a 3-tonne AC system, hence the reason why it was operating intermittently - it's now working!!

I used to be a telecoms engineer, so with some effort I could have faulted this myself, but it would have taken me a while to read up on AC system diagnostics and would have probably taken me weeks (plus buying a Fluke meter) to figure it out.

[Pib]

Yeap, they changed the start capacitor. And since you mentioned array, it could have included the run capacitor also...a combo unit containing two capacitor of different values...one value for the start capacitor and one for the run capacitor. At my last home which had a central air unit, the start and run capacitor were a combo capacitor unit and had around 5 wires running to it....it failed once...took the repairman about 5 minutes to diagnose the problem and replace the capacitor unit....he also changed the compressor switching relay that was nearing its end of life (burnt, pitted contacts). On my current split air systems the start and run capacitors are separate units.

Now a 3 ton unit is the same as a 36,000 BTU unit....that pretty BIG for a typical split air system unless maybe one condenser/compressor unit is hooked to two inside units. About the biggest home split air system you will see is around 24K BTU/2 tons....but there are so many variations of A/Cs now days. Glad you got it fixed.

Telecon engineer...for about a year I worked for a telecon company by going around to their central offices and calibrating/repairing equipment in their facility. Those are lonely places to work because some of them are not manned or in some cases just one person, two people if you are lucky,on a part time basis. But at least they have good air conditioning to keep all the telecon equipment cool.