Hi Everyone. I am new to the site but have been reading a number of threads and am finding them very useful. My background is in construction but I decided to branch out and start installing ductless mini-splits. I completed my first install and performed a 40 minute pressure test @ 250psi. I proceeded to the last step of vacuum pump down and this is where I ran into problems. My vacuum setup is as follows: two Appion core removal tools, an Appion 1/2" vacuum hose and CPS vacuum gage. I pulled down under 500 microns quickly and closed the valve to isolate the vacuum pump from the system. The value immediately went up to several thousand and slow increased so I re-opened the valve and allowed it to pump down awhile longer. After several attempts I got it to remain initially at 400um. It didn't stabilize however and kept creeping up around 20-40um per minute. I wasn't sure if it was my system leaking or my connections so I brought my equipment home to see if I could hold a vacuum with a simplier setup. This setup involved one Appion core removal tool, a vacuum gage, a T-valve and about 3' of 1/4" line with plugged flares. I would post a pic but am too new to do so. This time I pressure tested my setup at 620psi for 24 hours. Pressure was good after 24 hours so I released the nitrogen. I started Pulling a vacuum and again when closing the valve the value would creep up. I don't understand why I can't hold a vacuum after holding 620psi after 24 hours. I am not sure if my vacuum gage is the issue or something else. Anyone have any ideas on what I could try next? Your help is appreciated.