When I got my manifold, one of the nipples had some damage, so the Ebayer sent me a new one.
(The one in the top pic above). I think that I've seen them in the local AC shop..
Never use CO2, it's a liquid under pressure, and when warmed up it can go well over 900 PSI.
Use dry air or nitrogen from your local paint ball shop. Nitrogen is best.
If your pressure test is good, then the vacuum test should be good also.
Just remember that when it gets cold, the nitrogen pressure will drop a little.
If you can wait until it warms up, your pressure should slowly come back.
When you are done, bleed down the nitrogen to about 15 or 20 PSI.
Let that remain inside until you are ready to vacuum the lines.
You want to keep atmospheric air (in lines and hoses) to a minimum.
When pumping a vacuum, if it's cool outdoors and there is some moist air
in your lineset when you start, you will have to pump it out,
then hold and repeat a few times before all the moisture (or ice) is removed.
The ability to hold a good vacuum will depend on your hoses and pump connections.
I had little cut-off valves in my manifold hoses and when you turned one off or on, it would leak just a little.
I think some hoses allow tiny amounts of air to bleed in, and that lowers the quality of your vacuum..
Play around with your pump and gauges to get familiar with them.
After you run your pump and watch the micron gauge for a while,
you will get a feel of what your pump is capable of, and how it reacts
when you shut it down to hold a vacuum.
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