You need to do your research before asking for free engineering services. Here is some reading for you. http://www.gastmfg.com/vphb/vphbs1.pdf ■

There are 6 possible inlet conditions and these can be calculated if you know the outlet restrictions and the adequacy of the exhaust airflow.

Manifolding can be considered analogous to electrical factors. Roughly speaking, as usual, main pipes behave as series resistors and branches behave in parallel.

Without any realistic quantification of your system it is impossible to advise: eg. Do you have sufficient exhaust power to extract any air from the farthest inlet when the intermediate inlets are closed? ■

Mohan

I moved your latest post to the original one you started. There is no need to start another thread for the same request. I see that you are still looking for free engineering services. I would suggest that you hire a professional that understands vacuum systems. ■