Tusa ZEN AIR IQ-950, Owner'S Manual

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MODs affected by the PO2 limit set will not be displayed when FO2 for Gas 1 is set to
AIR.
Internally, the ZEN AIR keeps track of the O2 so that if FO2 for Gas 1 is subsequently set
for a numerical value, the O2 accumulated during previous AIR dives will be accounted
for in the next Nitrox dive (during that dive period and series of repetitive dives).
Once FO2 Gas 1 is set for a numerical value (21 to 50%) and a dive is made, the AIR
option is disabled until 24 hours elapse after the last dive. The AIR option will not be
displayed in Set FO2 Gas 1 until a full 24 hour Surface Interval has elapsed.
If FO2 for Gas 1 is set for 21%, it will remain set for 21% for that series of dives until set
for a higher numerical value.
If the FO2 50% Default is set Off, FO2 for Gas 2 and 3 will remain at their respective Set
Points previously selected until they are changed. If the FO2 50% Default is set On, FO2
for Gas 2 and 3 will Default to 50% after the dive.
The ZEN AIR is programmed to prevent FO2 for Gas 2 and 3 from being set at values
lower than the FO2 Set Point for Gas 1. Gas 2 and 3 can only be set to values equal to
or higher than the FO2 Set Points of Gas 1 and 2, respectively.
When setting FO2 for Gas 2 and 3, the lowest values available will be the Set Point of the
previous Gas set (e.g., If FO2 Gas 1 is set for 32%, FO2 Gas 2 can only be set at values
from 32 to 100%. Likewise, FO2 Gas 3 will depend on the setting for FO2 Gas 2.