Newbie with Vacuum pump choices?

I want to get into the Car Air Conditioning business here in Spain, and I need help on equipment choice. My question is, although I do not intend to get into the domestic air conditioning business at this time, I would prefer to buy equipment that can do both. I am guessing that a vacuum pump with the highest CFM rating is better than one with a lower rating. Is this correct? can you have too high a rating one, for small systems like car A/C?
Is there a bible of Oil/Refrigerant quantities for cars, that is available for European models?
Oil/Dye injector units. Do I understand things correctly when I say that they are a vessel with a screw top lid, you fill them up with the required amount of Oil, the oil is squirted into the evacuated system (via the incorporated valve), when putting new refridgerant into the system? If so, is there not a small amount of air left in the top of the oil vessel, which also goes into the system, or is it of no significance?
Sorry for so many questions, really would appreciate positive help in this matter.
TIA
Mark.
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On 7/5/2011 4:29 PM, Anti-Spam wrote:

Here in the US, the amount of refrigerant and oil needed is usually printed on a decal in the engine compartment of a vehicle. The information for the vehicle can be found in its service manual or the parts man at the dealer can tell you. Get the best tools you can afford and you would be better off adding oil to a system with a pre-charged canister until you can learn how to do it otherwise. You can purchase refrigerant that already has oil or dye mixed in the can with it. With time you can learn about injector units but get some experience with the way AC systems behave first. Experience is your best teacher. I own all sorts of injectors and equipment and know how to use them after 40 years of working on the stuff. I started out changing fan motors in window units and learned more and more from there. You may find some older fellow who won't mind passing on his knowledge for your help. Me and my friend who's 70 are getting to the point we can't scoot up ladders and work out in the sun all day anymore so we get some younger fellows to help us and we teach them what we know. :-)
TDD
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I would select a Vaccuum Pump for auto a/c as well as residential a/c in case you work on a home central air. I would therefore recommend a good brand like JB and at least a 3 cfm capacity / 2- stage is desirable . Ive had one for ions and it has always been reliable and effective. Change the oil in it regularly as the oil filters out the contaminants like air and moisture from the system. Also, if you want to greatly speed up the time to evacuate, then get larger diameter hoses as 1/4" hoses offer alot of restriction...although for car a/ c's it wont matter as much as for residential . Leave the vaccuum pump on a car a/c system for at least 1 hour and invest in a micron guage if you are really into doing a good professional job. Good luck in the career.
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Be very careful adding oil to automotive compressors Oil reduces cooling capacity it limit life of compressor it limit life of clutch it limit life of belts, you are better off with less oil in the system then more. when system totally empty it will take apx. 90cc average, in some smaller vehicle units perhaps even less the American standard passenger vehicle 90-120 expected.

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On 7/8/2011 3:50 PM, Grumpy wrote:

Also don't pull a heavy vacuum on car systems. It will suck the seals out or damage them.

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