How do I calibrate the VR3 for my rebreather at altitude?
Because your rebreather works on absolute pressure, the calibration gas in the VR3 must be adjusted for the ambient pressure when diving at altitude. For example: You are at an altitude pressure of 850mb. Therefore instead of setting the calibration gas as NX 99 ( as you would at sea level) you would set it as 99 x 850/1000 = NX 84 Then calibrate as per FAQ#4.
