RKI Instruments GX-2003 Manual - Manual (Page 88)

81 • Preparing for Calibration GX-2003 Operator’s Manual
To calibrate the GX-2003, you will need:
• Known calibrating samples of the gases being detected. The
combustible and toxic gas samples should have concentrations in
approximately the middle of the range of detection. An oxygen-
free source, such as 100% nitrogen is recommended for setting the
oxygen zero when using single calibration.
WARNING: When using auto calibration, the multi-gas cylinder
must have an oxygen concentration in the range of 10% -
18% oxygen.
• A gas collection bag with hose clamp
• A 0.5 LPM fixed-flow regulator or dispensing valve
• Calibration tubing
To calibrate the %LEL, Oxygen, CO, and H
2
S sensors at the same time,
automatically, with no need for a zero-oxygen source, you can use the
auto calibration feature with a 4-gas cylinder. If the H
2
S channel is not
active, then a 3-gas cylinder may be used for auto-calibration. This
document includes instructions for auto calibration with a fixed flow
regulator or dispensing valve and a 4-gas cylinder. This document
also includes instructions for calibrating one channel at a time using
single calibration.
Preparing for Calibration
Whether you will calibrate the Model GX-2003 using auto calibration
or single calibration, you will need to set the fresh air readings first
before setting the span readings for each gas.
1. Find a fresh-air environment. This is an environment free of toxic
or combustible gases and of normal oxygen content (20.9%).
2. Turn on the unit as described in “Turning on the GX-2003” in the
GX-2003 Operator’s Manual using the sample hose and probe.
3. With the unit on, perform a demand zero by pressing and holding
the ▲AIR button. The display prompts you to hold the ▲AIR
button.
4. Continue to hold the ▲AIR button until the display prompts you
to release the ▲AIR button. The GX-2003 will set the fresh air
reading for all channels.