4
Operation
Power On/Off
Press the On/Off/Set key to turn the meter on or off. During
warm-up, it will perform a 30 second countdown, then will dis-
play current CO
2
, temperature, and humidity. The meter
turns off automatically after 20 minutes of inactivity. To bring
the meter to non-sleep mode, press and hold SET and HOLD
for 2 to 3 seconds. You should see a character (n) appear on
the LCD display. At this point, let go of the buttons to cancel
the automatic power-off function.
Taking a Measurement
The meter measures continuously and updates the LCD
every second. With a significant environmental change, the
CO
2
sensor requires 30 seconds, and the RH sensor 30 min-
utes to respond. Note: Do not hold the meter close to the
face because exhalation affects the CO
2
reading.
Switch Temperature Measurement
Press the DP/WBT key to cycle the temperature display be-
tween air, dew point, and wet bulb temperatures.
Data Hold
Press the HOLD button to freeze the readings. HOLD will
display on the LCD. Press HOLD again to cancel the hold
function.
Backlight
Hold the MODE button for more than 1 second to activate
and cancel the backlight function.
MIN, MAX, STEL, TWA
Press the M
N
X
/AV button to switch between the normal, mini-
mum, maximum, and weighted average readings.
In MIN and MAX modes, minimum and maximum readings
for CO
2
, air/dew point/wet bulb temperature, RH will display.
In STEL and TWA modes, the display shows the weighted
average of the CO
2
readings for the past 15 minutes (STEL)
or 8 hours (TWA), as well as the current readings for air/dew
point/wet bulb temperature, and RH.
