Manual

Model GX-82A Instruction Manual
26 Hayward, California [phone]
4. The reading should fall to near zero for an oxygen-free sample, or
near the level of the low concentration sample. Adjust the reading
using the AIR/▲ or (SHIFT)/▼ switches.
5. Press ON/OFF/ENTER to complete the oxygen zero sequence.
6. Turn off the zero oxygen cylinder and disconnect it from the valve.