If you think it's the dry line turn off the valve to it. I think you have a leak so big you can't hear it. But maybe not try shutting off all the lines to the releaser and check vacuum. Then turn on each line separately. Also turn the valves off to your spur lines and check. It's a frustrating problem I've been there but work on it in small sections. Also if you had sap run this weekend and you turn on your vacuum you may be good because your leak may be froze. Hope this helps.