Fresh Air
This procedure determines the zero point of the sensor calibration curve for all the sensors that
require a zero calibration. For the oxygen sensor, Fresh Air calibration sets the point equal to
the concentration of oxygen in ambient air (approximately 20.9% volume).
Note: Fresh air calibration is performed on all enabled gas sensors at the same time.
To perform Fresh Air calibration on multiple sensors:
1. If using dry air, install the calibration adapter and connect it to a source of dry air.
Otherwise do not use calibration adapter to perform fresh air calibration.
2. At the Calibration Menu, select “Fresh Air.” Press [Y/+] once to enter the fresh air
calibration sub-menu.
3. Start the flow of dry air, if used.
4. Press [Y/+] to start fresh air calibration.
5. A countdown screen appears. You can abort the calibration at any time during the
countdown by pressing [N/-].
Honeywell MultiRAE Series™ 72 User Manual