I put the ntrogen tank on the liquid line, start brazing at the closest joint to the nitrogen, then work my way toward the coil, then the suction side back out to the condenser. I'll tell yall somthin no one has mentioned yet. What about when you remove a cooling coil on a system that has been in service for a while? If it has been freezing up, there will be excess oil in the coil. When you braze it back in, it will flare, smoke, and burn like hell. Not if you use nitrogen. Nitrogen displaces the oxygen, therefore combustion cannot occur. I've always believed in putting driers as close to the TXV as possible. Plus if it is inside, it will never rust out. How many times have you guys found driers leaking that were outside at the condenser, layin on the dirt and grass. Not tryin to tell anyone how to do their job, just tryin to offer some of my thinkin.