Specifications

CO
2
Analyzer 2810/2815/2820
Instruction 19-9222
14
3.7.2 2820 Calibration Procedure
3.7.2.1 N
2
Calibration
The following procedure uses 100% N
2
to zero the analyzer. (Fresh ambi-
ent air that is assumed to contain 340 ppm CO
2
can be used if N
2
is not
available.)
Important! DO NOT perform an N
2
calibration after sam-
pling high concentrations of CO
2
gas. Also, be careful that
your breath does not affect this procedure.
1. Switch ON the analyzer. But before proceeding, allow the analyzer to
sample fresh air for 5 minutes with its internal pump turned OFF.
CO2 HR % CO2
Analyzer 00.00
2. Press and hold down the f
2
button until the ‘User Cal’ screen is dis-
played. Note that battery status is rst displayed for approximately
2 seconds.
User Cal
Wait until the analyzer automatically switches to its ‘N2/Gas’ screen
before proceeding.
f1-> N2
f3-> Gas
3. Using the calibration accessories listed in Section 4.1, attach a 100%
N
2
gas cylinder to the inlet of the analyzer as shown in Figure 3. Then
adjust the regulator attached to the gas cylinder for an outlet pressure
of 2 psi (equivalent to a ow rate of approximately 120 cc/minute). If
N
2
is unavailable, turn ON the analyzer’s pump and allow it to draw
in fresh air for at least 30 seconds before proceeding.
Important! When using N
2
gas, do not attempt to calibrate the
analyzer if the pressure gauge closest to the tank reads below
5 psi.
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