I can pull a vacuum equal to whatever the ambient pressure is, according to
my gauge set. Never had a moisture problem. Heck, some people use vane
pumps or even those venturi gadgets - now THOSE can't pull a deep vacuum.
But a real HVAC compressor will pull as deep a vacuum as you need to boil
off any water. Of course, I do leave it on for at least an hour before
charging - water will evaporate at ambient pressure, so a deep vacuum just
speeds things up.
> > I heard a refrigerator compressor can be used as a vacuum pump
> > to pull a vacuum on an automobile, or other, AC systems. Anyone have
> > experience with this?
> It works OK if you're just trying to suck the air out, but doesn't pull a
> hard enough vacuum to boil out any accumulated moisture (especially from
> dryer). So if you have a moisture detector in the system, it will turn
> yellow again almost immediately. But, I've never seen a car with a
> detector, so you'll probably never know the difference.