So recently I’ve been working with a brand new Across International 1.9 Cubic Foot Vacuum Oven.
To measure a deep vacuum I use a Fieldpiece SVG-2 Digital Vacuum Gauge, it reads in microns of mercury.
Unfortunately I couldn’t get it to pull a vacuum that the digital gauge could read anything but OL (Over Limit).
I was using a 9 CFM Yellow Jacket SuperEvac Vacuum Pump and tried running it for 9 hours straight! No luck.
From the internal shutoff valve there is a T-Junction to the Vacuum Outlet and a Gas Inlet on the back:
From what I can tell there is only a little plastic cap between open air and my vacuum, no gaskets or anything..
So I just removed the gas inlet connection, luckily the hose was just barely long enough:
Problem solved! I can now pull a deep vacuum, no problems.