i just bought a new micrion gauge today. I was on a roof all day working on a a/c unit, that somebody cut the line over the winter. It has water in the line so I need to see if i'm pulling a deep vac, I can not get a reading on the micrion gauge,I had it set up in series with the vac pump it showed bars in the beginning, and then it show atm on the display no numbers at all.I am going back in the morning to work on the unit. thanks for your replyes. also on the suction drier which way does the arrow face? Toward the condenser or towards the evape? I'm finishing school in June trying to make some money.