I am finally after many years considering buying a micron gage. am i correct in assuming that a leaky line set will not produce a 500 micron vacuum due to the leak and can help diagnose leaks in in accessible lines? Can i use the micron gage to isolate the lines and coil and achive a 500 micron vacuum to insure i'm not putting a new condensor or compressor on a leaky system? In a typical scenario how long would it take the 500 mic vacuum to bleed down if i had a leak? I know these are simple questions, but i haver never used vacuum to diagnose leaks, only long term nit pressure tests and electronic leak detectors, etc. thanks Any recommendations on brands and types? we are res light commercial dealer, mostly ac heat pumps and some light refrigeration when we can't get out of it.