Specifications

Instruction 0019-9321
Comfort Chek 100/200
10
3.7 Zeroing the Gas Sensor(s)
Zeroing the gas sensor(s) consists of performing an Air Calibration in
fresh outside air, which sets the CO
2
sensor to read 340 ppm (Models 100
and 200) and the CO sensor to 0 ppm (Model 200 only).
Important! It is essential to ensure that the instrument is in
fresh air before attempting an Air Calibration. If this condi-
tion is not ensured, incorrect gas readings will occur. Also be
careful that your breath does not affect this procedure by keep-
ing your exhaled breath away from the instrument’s gas inlet.
1. Switch ON the instrument, and then allow it to sample fresh outside
air for at least 5 minutes.
When calibrating a Model 200 and after the instrument has warmed
up, turn ON its pump for 30 seconds to purge the sensor area, and
then turn the pump OFF before proceeding to Step 2.
2. 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 approximately
2 seconds.
Air Cal
3. 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 instrument is only exposed to fresh air. If the proce-
dure is still unsuccessful, then the instrument must be returned to a
Bacharach Service Center for evaluation.
4. This completes the Air Calibration procedure.