EN
41
• Press ALARM ON/OFF button to activate
CO
2
ALARM function,
symbol appears.
• When CO
2
value goes up to desired upper
limit value, alert rings and
flashes.
ALERT MODE:
• Lower than 200 ppm, rings every 3 seconds
• Lower than 500 ppm, rings every 1 second
• Over 800 ppm, rings twice every 1 second
• Press ALARM ON/OFF button to quit alerts,
alert period is 2 minutes.
• Press ALARM ON/ OFF button, turn off CO
2
ALARM function,
disappears.
• When CO
2
value goes up to the desired
lower limit value, only
flashes, no alert
rings.
AUTO CALIBRATION
The automatic calibration function means
that the sensor will intelligently judge the
zero point based on the environmental
concentration and calibrate itself after a
period of continuous operation (7 days).
Calibration takes place automatically every
24 hours after the unit has been switched
on. The zero point of automatic calibration
is 400ppm.
MANUAL CALIBRATION
• Find an area with fresh air, CO
2
value lower
than 400ppm.
• Press and hold UP button to enter manual
calibration mode. CAL letter flashes. This
process takes 20 minutes, after 20 minu-
Summary of Contents for 7004020CM3000
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