Jason, You can close each changeover valve to the waste turbo by holding down the keyboard control key followed by clicking on the valve. Andy _____ From: Stable Isotope Geochemistry [mailto:[log in to unmask]] On Behalf Of Jason Curtis Sent: Monday, November 23, 2009 12:39 PM To: [log in to unmask] Subject: [ISOGEOCHEM] How to isolate changeover valve on Finnigan 252 Hi All, Does anyone know how to close all the valves in the changeover block in a Finnigan 252 using Isodat 2.0? I need them all closed for maintenance. Seems like it should be do-able but they appear to have made the software completely dummy proof. If there is no software solution, I figure I can just remove air pressure to the valves manually. My assumption is that they are normally closed valves. Can anyone confirm this? Thanks, Jason Jason Curtis, Ph.D. Stable Isotope Mass Spec Lab manager Senior Associate-In Geochemistry Department of Geological Sciences 241 Williamson Hall University of Florida Gainesville, FL 32611 [log in to unmask], office 352-392-2296 lab 352-392-3344, fax 352-392-9294