Hi, I'm curious about how vacuum systems work... I was advised to try posting this here, hopefully it's the right place. So if you're designing a high vacuum system, how do you actually operate it? For example if you have a chamber connected to an oil diffusion pump connected to a rotary pump, do you have to open the valves first and bring it up to atmospheric pressure? Then close the valves and start the pumps? Once you reach your lowest pressure, do you turn off the pumps and then open the valves? I'm confused about the order of these things.