Also when you close a ball valve there is believe it or not an area where a higher pressure is stuck until you close the valve. IF you close the ball valve or you CRT you usually can hear the air if it was sitting in the truck awhile..
I noticed several things.
You need to be able to isolate all of the hoses completely from the system when pulling a vacuum. You need core tools and a brass connector to isolate your vacuum gauge. All hoses, even Appion hoses leak. They just leak at a lower leak rate then standard hoses.
All connections leak, again it is the leak rate that matters.
The recovery tank valves my not be rated for vacuum. Make sure that the valve is completely back seated. The packing might be leaking. I see that a lot. Try an empty refrigerant cylinder, they are a lot less likely to leak.
There is nothing wrong with using the vacuum rated manifold, it allows for several more connections if you are working on a commercial system. It is a must have for very large systems to get the required flow from a larger pump. For residential systems, a simple brass tee will do.
Read through this vacuum primer before you throw in the towel, you are making a few simple mistakes, I know the information here will help. If you have questions, PM me with a phone number to help.
After wiping the egg off my face, had to put just one more video up....
Couple more things,
When the core tools are isolated you are looking at leak rate, when open it is really pull down rate. Pull down is negative, rise is positive.
Cycle your core tools during pull down. A small amount of gas/air gets trapped in the valve packing. This will minimize the initial rise when you isolate the hoses.
Leak rate is in microns/second. If you multiply the leak rate x 60 seconds/min x 10 minutes you can get the approximate rise after 10 minutes. Under 500 is acceptable. at a leak rate of .2 microns/second that would rise 120 microns over 10 minutes.
The calibration of the FP and theBluvac were very close at low vacuum. It is typical for the Bluvac to be faster simply due to the technology used. They also may have different calibration points. Maybe one at 500 microns and one at 250. I am not sure. But I have seen a lot of different vacuum gauges do not agree until they are in a deeper vacuum.
Glad I could help.