A newbie question

[<ramrod]

//Some manufacturers have a micron range that they want their system pulled down to, so therefore, JB can only suggest a micron reading. Our suggestion is to pull a system down to 250-300 microns only if you are also pulling a vacuum on the compressor. Going below 250 microns, you will start degassing the oil in the compressor and it will not be the same lubricating oil as it was originally. The oil will only degass and will not suck up into the vacuum pump.\\

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//This is from CPS:

2000 microns lowest average industrial requirements for A/C systems 1000 microns medium average industrial requirements for A/C systems 600 microns highest average industrial requirements for A/C systems 400 microns lowest average industrial requirements for refrigeration systems 200 microns medium average industrial requirements for refrigeration systems 100 microns highest average industrial requirements for refrigeration systems 25 microns deep vacuum for special requirements and for testing of vacuum pump efficiency\\

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//There are many evacuation level recommendations including the statement ?evacuate the system to below

200 microns.? This should not be considered. Note we say ?system? because it is possible to evacuate piping or some component other than the compressor to below this level. Refrigeration oil has a vapor pressure and by going below 200 microns, you will degas particles of the refrigeration oil. By changing the makeup of the oil, it will no longer be a true lubricating oil. Remember, hydrofluoric and hydrochloric acids, and their pal, moisture, do collect in the oil. Having nothing but time on their hands, they effectively destroy pull down and act as an abrasive on internal surfaces. If left sitting in an idle pump, these culprits keep busy by rusting and corroding internal surfaces. Deep vacuum pumps need a fill or two for every job. In order for your pump to pull a near perfect JB\\

[Tony944]

wrote in message news:KOwxr.7744$% [e-mail]...

Some of guys answers of pulling vacuum on systems got me interest and what got me most that you believe what manufacture tell you, well gents those that believe are fools, first of all you need to work for manufacture and go on seminars to manufacture and see for your self what is done and how is done. Vacuum should be pull down to 50 microns on any new refrigeration system. If refrigerant was already in the system refrigerants that use POE oil it may take hours are days to get down to 50 microns so it is acceptable if you can get down to 100-300 microns, However it is also necessary to have system pressurize because there are times that system may leak in one direction but not in the other. Thec. At site most determined how he/she will proceed and what he/she will need to do the job right. If system lost gas on the high side or low side it makes large difference and if system has pressure safety switches that will shut down system if refrigerant is lost. There is another phenomena how cold this system is use for we must remember that all material shrinks with low temperature and expand with high. These phenomena may cause unit to leak at one temperature but not the other, I have seen and experience these problems on my own, as some of us may say it will drive you to drink even so I don't drink. Pressure testing is necessary but one most take precaution, up to 300 PSI any system can be check, sealed units you can go up to 400 PSI. Semi hermetic unit I would not advise any one to go above 300 even so I have. By the way I never heard of 45% silver on less is on special order so that Manufacture will need to sit bare assed on fire before I would believe them!!

[PaxPerPoten]

Pressure testing and pulling a deep vacuum seem to be 2 different animals. A deep vacuum seems to insure no leaks ..Where-as many times a pressure test seems to miss them.