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auto ac vacuum pump micron ratings.

yorled on Wed June 03, 2009 11:56 PM User is offline

I would like to buy an auto ac electrical 110 vac vacuum pump which can draw down between 150 to 50 micron but I am strapped for cash so I would have to settle for one which is a little less effecient .I would like to know if a pump is rated to draw 50 micron and draws down a system and another pump is rated to draw down 100 micron but the 100 rated pump draws a system and repeat a draw,i.e, draw a system two times in a row, is the net effect the same when one compares how the two(2) pumps worked,given the circumstances mentioned above?
what I want to bring about here is;given the fact that I do not have a 50 micron drawn pump ,I could still get the same result with a 100 micron rated one but I would have to double up on my draw.
Thanks in advance for a very quick reply!!

Chick on Thu June 04, 2009 12:20 AM User is offlineView users profile

Without getting to technical, any one of these Mastercool vacuum pumps is more than enough for automotive AC work. Just stay away from air operated pumps.. The smaller ones listed here just take a little bit longer to pull down, but even charging stations are seldom run long enough to pull the pumps ultimate vacuum (microns). Buy the one that best fits your needs. For occasional DIY'er use, the smaller ones will work fine.. Hope this helps..

Email: Chick


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TRB on Thu June 04, 2009 10:25 AM User is offlineView users profile

I had a long discussion with my Mastercool rep on so called Micron listings. Bottom line is Micron listings are done in laboratory conditions. Any quality pump with boil off moisture (1000 Microns or below) if said pump is working correctly. You can't beat the economy 5 cfm dual stage pump in my opinion but all the Mastercool pumps will work fine for standard size auto a/c systems.


When considering your next auto A/C purchase, please consider the site that supports you:

marvin-miller on Thu June 04, 2009 8:05 PM User is offline

Are you doing auto a/c? The reason I ask is that you'll never see an auto A/C system go down to 50 microns....

The lowest I've seen was 300 and it was a rarity. My target reading is 750 microns. At that level there is zero moisture left in the system and it's ready to charge. I can get 50 microns off my pump if I directly plug my thermistor gauge straight into the pump. If I place it at the end of a standard A/C hose and run that straight to the pump the ultimate vacuum level decreases. This is a typical result (the longer the hoses the less ultimate vaccum pulled).

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