Extech Instruments CO230 User Manual page 9

MANUAL CO
Recommendation: The manual calibration should
be performed by a qualified laboratory every 12
months.
1. Place the meter in the 400ppm calibration
chamber. Turn the meter on and hold down
the CAL/ESC and ▲/DP WB buttons simultaneously to enter CO
calibration mode. 400ppm and "CAL" will blink on the LCD.
2. Wait approximately 5 minutes until the blinking stops. The
calibration is then complete and the meter will automatically
return to the normal mode.
3. To abort the calibration at any time, press RESET.
RH CALIBRATION
The meter is calibrated to standard 33% and 75% salt solutions.
To abort calibration press and hold the RESET button for > 1 second.
CAUTION: Do not calibrate the humidity without standard calibration
salt bottles. Otherwise, the meter will have to be returned for
specialized calibration service. Contact Extech for calibration salts or
calibration service.
33% calibration
1. Plug the sensor into the 33% salt bottle.
2. Press and hold CAL/ESC and MXN/AVG/▼ to
enter the 33% calibration. "CAL" and the
calibration value (32.7%, if at 25°C) will blink on
the LCD with the current temperature shown
on the left.
3. The meter is now calibrating and will finish in
approximately 60 minutes (when "CAL" and the humidity
reading are no longer blinking).
CALIBRATION
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