Flush with nitrogen and then place a vacum pump on the system and let it run for as long as possible. On large chillers if it will evacuate down to 400microns that is a pretty good target for all of the moisture to be out of the system. Some with automotive a/c experience may have a better target for this application. Nitrogen can be purchased from most welding and commercial gas outlets. The cylinder is connected to the system just like a refrig bottle via your guage hoses, and sent through the system and vented to atmosphere..

92 Extended Cab 4x4, 3.0 5-Speed Scratched, Dented and Rusted.