Technical information

SYSTEM SETUP / CALIBRATION
3/31/2008 Rev. 4.3 5-4
5-0). A well-calibrated flow meter with little backpressure should be used as the standard. If for any
reason an error was made during the calibration procedure pressing the
key will also return
back to the beginning of the flow calibration procedure without saving any changes made. Once the
calibration procedure is competed, in a few moments the instrument will reset and return back to the
above screen display.
CO2 AND H2O
NOTE: For greater changes in ambient temperatures between sample measurements, it may be
necessary to recalibrate to CO
2
“zero setting” at each temperature (i.e. O°C sample and 40°C sample).
Suggested calibration schedule: ZERO setting once a week for CO
2
and H
2
O; SPAN setting once a
week for CO
2
. Check H
2
O once every six months.
This instrument allows calibration with a range of CO
2
from 100 to 1000 ppm, and H
2
O from 1 to 7.5
kPa.
ENTER to select Calibrate CO
2
To change the calibration of CO
2
, scroll to choose the “Calibrate CO
2
” under the “ENTER to select”
function. While the instrument stabilizes to the setup state, it will first ask if you want to calibrate
zero.
Start to set zero, else Exit
Press the
key to calibrate the zero or press the key to skip the calibrate zero function.
Use 0 ppm CO
2
gas Press START/ENTER
Connect dry nitrogen or soda lime and allow the zero ppm CO
2
gas (dry nitrogen or soda lime) to
flow for approximately one minute (three minutes for soda lime) prior to pressing the
key to
flush the system completely. Always use a “T” connector. A small amount of flow out of the one-
meter tube ensures a sufficient quantity of gas is flowing to the system (see Figure 5-1) in the gas line
when supplying gas from a low-pressure regulator in order to avoid excessive flow through the
system. Alternately, use soda lime connected between the intake and exhaust
with the small plastic
tube where the chamber usually goes to form a closed loop. (See Figure 5-2)