LG AC gas oil choke ?

Crazy_Eddy

Crazy_Eddy

Staff member
Super Mod
I have a 2 year old LG AC that has thrown up a CH38 error code for low gas issues.
The LG service engineer checked the gas pressure and found it to be ok. He released a bit of the gas and showed it having a slightly oily residue. He says the compressor oil has entered the indoor unit coil and 'choked' it which is why the gas isn't able to flow through.
His solution is to release the gas, which will bring out the oil, and refill fresh gas.
However he cannot say for sure what caused this. And no plans to refill the compressor oil.

Does anyone have a similar experience?
I have seen a few youtube videos on this, all by third party Indian techs, but don't see any official guidelines on this.
 
If this is a known issue + replacing the gas is a permanent fix, go for it

But if the oil leakage continues, then this issue will keep repeating, until the day the compressor dries and seizes up

I'd suggest you try escalating this matter up the chain first to sort out the oil leak issue. If they too are clueless, then it might be worth checking with a local AC service outlet about refilling the oil.

For reference, my split AC just turned 10 years old and the only maintenance i did was cleaning the air filter. ACs are sealed systems that don't require maintenance as such
 
Is there a significant height level difference between the inner unit and outer unit placement? If yes then this can cause all sorts of problems. Ideally they should be at the same height.

Also the distance between the two should be as short as possible.

Compressor oil in Refrigerant Gas is considered okay in small quantity but yours seems to be severe.
 
n1r0 said:
If this is a known issue
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Have heard of this in car AC systems; usually old ones. Compressor seals may wear out after a long while (or) if the compressor had to do some heavy-lifting such as this :
Heisen said:
significant height level difference between the inner unit and outer unit
Click to expand...

Not sure if such after-market seals are available for home AC units; ask around.

Better to figure out the root-cause and fix it or replace compressor entirely, as running without circulation of coolant may overheat the entire system, primarily the compressor, causing the issue to repeat sooner and sooner.
 
@Heisen
> Is there a significant height level difference between the inner unit and outer unit placement? If yes then this can cause all sorts of problems. Ideally they should be at the same height.

How much height difference is tolerable ?
Didn't know this, new a/c fixtures in my place is at least located ~15ft far and ~6ft high if am guessing right.
 
I've had the same compressor oil issue recently with our Daikin AC. The service guy took all the gas out using vacuum pump then refilled fresh gas. He also mentioned that the compressor oil cannot be refilled but this fix should last for a few years.
 
TEUser2K1 said:
How much height difference is tolerable ?
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I have no idea, but after quick googling and understanding some of the terminologies, it seems that the recommend height and distance between the two units should be mentioned in the manual of the AC and it varies with the model.

One thing for sure is exceeding the maximum distance puts strain on the compressor.
Also it seems like there is also a minimum distance to be maintained, for efficiency reasons.
 
rockstah said:
I've had the same compressor oil issue recently with our Daikin AC. The service guy took all the gas out using vacuum pump then refilled fresh gas. He also mentioned that the compressor oil cannot be refilled but this fix should last for a few years.
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Oh :( Did he have any clue what caused it? Is it performing as well as before after the fix?

Heisen said:
Is there a significant height level difference between the inner unit and outer unit placement?
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This was one of the first things I checked.
The outdoor unit has a sticker showing it's rated for max 10m elevation/height, 20m length. Mine is about 5m length, possibly 4m height, so well within spec.
 
If you are operating within standard parameters, and if the compressor has extended warranty - most usually have 10 years or so, why not ask to change the compressor under warranty?
 
Crazy_Eddy said:
Oh :( Did he have any clue what caused it? Is it performing as well as before after the fix?
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The next day capacitor went kaput, after changing that it's been running good and cooling is great too. Kindly check if it's possible to get it changed under warranty as suggested. I asked similiar question to the service guy who said it might be possible to get it fixed under warranty.
 
This can happen due to various reasons, its always due to poor installation. When the unit is running on low gas aka correct term refrigerant due to poor installation, the bottom of the compressor will be freezing cold, this causes the oil to mix with the refrigerant which is in a liquid state and this then chokes the capillary tube or in the case of a inverter AC, the electronic expansion valve, it can also choke any small diameter tubes located any where in either of the coils outdoor and indoor. Because this unit was not installed properly without vacuuming the lines, moisture present in the air would have mixed with the oil.
If the pressure in the meter seems fine but the unit doesn't cool despite cleaning the indoor and outdoor unit, then it means the meter is showing the pressure of the remaining refrigerant+ Air/moisture/gunk present in the system.


Had they done a proper installation when it was new, none of this would have happen. Off course in rare cases due to manufacturing defects or the environment its operating at can cause corrosion, which may lead to a slow leak.

Now the only fix is to drain all the refrigerant out both in gas and liquid state, refill the refrigerant in liquid form by putting the cylinder upside down and then charge the refrigerant exactly as per the weight mentioned in the outdoor unit sticker, this is done by using a highly accurate weighing machine. Prior to filling the refrigerant, the unit will have to purged with nitrogen to flush out the contaminants and then use a 2 stage vacuum pump to clear the lines off air and moisture that will be present in the lines and the indoor unit. Make sure the Vacuum is done for 15 min and if its a single stage pump for 30min and make sure the vacuum guage doesn't go back to zero even even after the vacuum pump is switched off for a atleast 15min. If it goes back to zero that means there is a leak somewhere.
 
adder said:
this then chokes the capillary tube or in the case of a inverter AC, the electronic expansion valve, it can also choke any small diameter tubes located any where in either of the coils outdoor and indoor.
<..>
the unit will have to purged with nitrogen to flush out the contaminants
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Yes, this is my current concern. They did not come prepared with nitrogen or anything to flush out the unit.
They will be happy to waste refrigerant for flushing, but R32 still has a high GWP of ~675, which I'm not comfortable with.

I also realised the port to connect the pressure gauge is on the low pressure side, i.e. after the indoor coils which are supposed to be choked. So I'm confused why it is showing any pressure at all.

vivek.krishnan said:
If you are operating within standard parameters, and if the compressor has extended warranty - most usually have 10 years or so, why not ask to change the compressor under warranty?
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Yeah this is the angle I will try to push. But the compressor is still running, even though the service tech admits the compressor must have overheated and pushed out the oil. This AC is used in the nights, at reasonable 27C temps, so I don't feel it is a heavy load.
 
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