44 • Chapter 5: User Mode and Calibration
GasWatch 3 for CO and O
2
6. Press and hold AIR until the screen prompts you to release it.
7. If the fresh air adjustment passes, the instrument returns to the
AIR
item in the
GAS CAL
menu.
8. If the fresh air adjustment fails, “FAIL AIR” displays. Press and release POWER/MODE
to acknowledge the failure. See pg.73.
Performing a Span Adjustment in A-CAL
The
A-CAL
item only appears if
E-CAL
in User Mode is set to
OFF
(factory setting). If
E-
CAL
is set to
ON
, see pg.49 for calibration instructions.
Preparing for Span Adjustment
To adjust the span on the GasWatch 3, you need:
•
Calibration gas cylinder (RKI Instruments recommends using 50 ppm CO in N
2
)
•
0.25 LPM fixed flow regulator
•
Non-absorbent tubing
•
Calibration cup
1. Confirm that the GasWatch 3’s calibration gas values match the concentrations listed on
the calibration gas cylinder as described on pg.54.
2. Confirm that the regulator knob is turned all the way clockwise. Screw the 0.25 LPM
fixed flow regulator onto the calibration cylinder.
3. Install the calibration cup onto the GasWatch 3. The calibration cup has an indicated flow
direction. Be sure the calibration cup is installed in the correct direction and that it is
pushed on all the way.
4. Use the tubing to connect the regulator to the inlet of the calibration cup.
HOLD
Air
RELEASE
AdJ