I hope this helps to give you that behind the scene look at this mast. Most pilots that I ask questions about this system are not aware of exactly how it works due to the negative transfer of knowledge by learning the Cessna system in most of the aviation books.
NOTE: There is a correction needed at the 2:22 mark. The static and the static/drain is stated backwards. I will fix that in the video shortly.
Let me know if you have any questions.
Todd