Gas exchange notes 

  For VO2 Modes 3 and 5 and Mask Modes 1 and 3, and for CO2 Mode 2 and Mask Mode 1, the positions of the flow meter and gas analyzer can be 'flipped' with no effect.  In other words, the either the gas analyzer or the flow meter can be last in the 'chain'.  

  The plumbing arrangement shown for O2 Mask Modes 4 and 5, CO2 Mode 4 (measuring flow rate on undried gas) is not recommended except at low temperatures or if you are sure relative humidity in the gas stream is low.

  For similar reasons, the plumbing arrangement shown for CO2 Mask Mode 3 (measuring CO2 concentration in undried gas) is not recommended.