I'm working in the OEM (Factory Service) setting, this time for a Com. Ref. manufacturer. I was shown how to do compressor gasket replacement, liquid line dryer core replacement, oil filter cartridge replacement, etc. without using nitrogen or a vacuum pump. There's no way I did any of these things when working on a Chiller. Is this ethic normal in Com. Ref. Svc.? I've ran Rack service before with HBS and CBSS, always using nitrogen and a vacuum pump when a system was opened.