Specifications

CO
2
Analyzer 2825/2830/2835
Instruction 0019-9320 13
3.7 Air Calibration
An air calibration consists of zeroing the gas sensor(s) in fresh outside
air, which sets the CO
2
sensor to read 340 ppm or 0.03% (2825 / 2830 /
2835) and the O
2
sensor to read 21% (2825 / 2830).
Important! It is essential to ensure that the analyzer is in fresh
air before attempting an air calibration. If this condition is
not ensured, incorrect gas readings will occur. Also be careful
that your breath does not affect this procedure by keeping your
exhaled breath away from the analyzer’s gas inlet.
1. Switch ON the analyzer, and then allow it to warm up while sampling
fresh outside air for at least 5 minutes.
2. After the analyzer has warmed up, turn ON the pump for 30 seconds
to purge the sensor area; then turn the pump OFF before proceeding
to Step 3.
3. Press and hold down the f
2
button until the ‘Air Cal’ screen is dis-
played. Note that battery status is fi rst displayed for 2 seconds.
Air Cal
4. Keep the f
2
button depressed until the display shows:
Air Cal
OK
If the procedure was unsuccessful, or if the f
2
button released prema-
turely, then the message
Air Cal
Failed
will be displayed. If this happens, retry the Air Calibration pro cedure,
ensuring that the analyzer is only exposed to fresh air. If the proce-
dure is still unsuccessful, then the analyzer must be returned to a
Bacharach Service Center for evaluation (refer to Section 4.2).
5. This completes the Air Calibration procedure.