RKI Instruments GX-2001 Canadian Version - Manual (Page 15)

Model GX-2001 Operator’s Manual Start Up • 15
Performing a Demand Zero
Although the GX-2001 sets the fresh air readings automatically (auto zero)
when it is turned on, it is also possible to set the zero reading manually
(demand zero) for the target gasses to ensure accurate gas readings in the
monitoring environment.
1. Find a fresh-air environment. This is an environment free of toxic or
combustible gasses and of normal oxygen content (20.9%).
2. With the unit on and in Measuring Mode, press and hold the AIR button
for about three seconds to allow the Model GX-2001 to set the zero
reading for HC, CO, and H
2
S and to set the span for O
2
.
While you are pressing the AIR button, the LCD displays “Hold,” a
prompt for you to keep pressing the AIR button.
3. When the zero readings have been set, the LCD displays “Adj,” which
prompts you to release the AIR button.
Turning Off the Model GX-2001
1. Press and hold the MODE/POWER button for about five seconds to
turn off the unit.
2. The buzzer will sound and the LCD back light will flash.
3. Release the button when the LCD is blank. The unit is off.