I will admit in the past that I haven't always ran nitrogen through my refrigerant lines while brazing. But this spring and summer I want to be very meticulous in doing so. The main reason I want to do this is because of the new company I now work for. From what I have heard and from questions I have asked I know that no one here does it. Not only that, they don't use micron gauges while pulling a vacuum on their systems. They said that they installed around 200 AC's/Heat pumps last year and I am just wondering how many of these systems are going to have potential problems because they didn't do either. I'm gonna make sure everyone is doing it by this spring and I don't care what my boss tells me to do. Just a few weeks ago I had to teach them that you must use primer when putting together PVC. Sure there are other things I will find, but this is it so far. My question is, on the method of flowing nitrogen while brazing. Do I need to hook the lines up to the OD unit first, so I can use the service ports as taps to introduce nitrogen to the system or is there an easier way so I can have it flowing from the beginning? Sorry, if this is a stupid question but it shows you how many people I know that don't do it, and I've been doing this for 11 years.