GasWatch 3 for CO and O
2
Chapter 5: User Mode and Calibration • 45
Performing a Span Adjustment
1. While in User Mode, press AIR to scroll to
GAS CAL
.
2. Press and release POWER/MODE. The
AIR
item appears.
3. Use AIR to scroll to the
A-CAL
item.
4. Press and release POWER/MODE. The display shows the gases assigned to Cylinder A
and their assigned calibration values (see pg.54 if the calibration values do not match the
calibration gas cylinder’s concentrations). The bottom of the screen alternates between
“CYL A” and “A-CAL”.
5. If necessary, use AIR to scroll to the Auto Cal screen for the gas(es) you want to calibrate.
As shipped from the factory, CO and O
2
are assigned to Cylinder A.
6.
Make sure the GasWatch 3 has been turned on for at least 45 seconds before
continuing.
7. Press and release POWER/MODE.
8. The gas reading flashes and the bottom of the screen alternates between “APPLY” and “A-
CAL”.
NOTE:
To back out of the gas application screen without performing the calibration, press
and release AIR and POWER/MODE together.
9. Turn the regulator knob counterclockwise to open the regulator.
10. Allow the gas to flow for 1 minute.
GAS CAL
A-CAL
CYL A
0.0
%
50
ppm
A-CAL
0.0
%
50
ppm
APPLY
20.9
%
0
ppm
A-CAL
20.9
%
0
ppm
