Dual ports open because of a pressure difference between the top and lower ports, correct (the upper port is exposed to air pressure help keeping the gate closed in conjunction with the spring)?? The upper port is used to regulate the pressure via that (MB) controller.
The differential is what I am referring to as "vacuum" and not the port itself actually seeing vacuum
In further thought, if the MBC is twisted shut, then the upper source in essence, is negated and it essentially becomes a single port. In that case, yes, having the MBC fully closed will basically relegate you to watsgate spring pressure.
I agree with your statement
The differential is what I am referring to as "vacuum" and not the port itself actually seeing vacuum
In further thought, if the MBC is twisted shut, then the upper source in essence, is negated and it essentially becomes a single port. In that case, yes, having the MBC fully closed will basically relegate you to watsgate spring pressure.
I agree with your statement