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Nobby
30-06-2002, 03:37 PM
Ok, Dumb question. As a newbie I am curious how oil, is introduced into a A/C system, or a refrigeration system come to that. I mean once refrigerent is recovered, some oil is recovered also isnt it? I also presume oil must be changed once in a while. And if a system is flushed with some inert gas, this will together with a vacuum pump pull out oil?
Thanks in advance chaps
Stephen:)

terrygoodrich
21-07-2002, 03:49 PM
Oil comes in the base of a new compressor. Normally, no more needs to be added if the system is designed not to trap oil. If it needs to be "topped off" or replaced it can be pumped with a little hand operated pump available from your wholesaler. Unless the oil is contaminated or subjected to excessive heat, it never needs to be replaced. The system is sealed from the atmosphere so the oil should never be contaminated. On a few occasions, I have replaced a defective compressor and found the new one to run noisy with high amp draw. The problem was too much oil in the system. I determined that the oil from the bad compressor was trapped in the system and the new compressor came with a full charge of oil. I had to remove some. Modern filter/driers do an amazing job of removing contaminants and restoring oil to good condition. Recovering refrigerant will remove some oil from the system, depending on where the oil is, where your hoses are connected and whether you are removing liquid or vapor. It should not be a significant amount because most of the oil should be in the compressor crankcase.

Dan
21-07-2002, 04:36 PM
Good observation Terry. No single answer addresses Nobby's questions.


Ok, Dumb question. As a newbie I am curious how oil, is introduced into a A/C
system, or a refrigeration system come to that. I mean once refrigerent is
recovered, some oil is recovered also isnt it?

If we are just talking about evacuating a charge and recharging, some oil will be removed from the system. Most of the time this should be negligible but it does bear watching upon restart.

If you are changing a compressor, you have to know whether the replacement compressor has oil in it or not.

A vacuum pump will not remove any significant amount of oil.


I also presume oil must be changed
once in a while.

I disagree. Certainly not on your home refrigerator or a/c unit, right? After a compressor burn out, or in a system that has obvious oil deterioration from overheating, or severe moisture problems, an oil change would be a good idea.

Nobby
22-07-2002, 04:42 AM
Thanks Guys, Pretty much covered all my questions. I say Guys, never have I seen a female a/c tech so far, hope I didnt upset anyone?
Stephen