Extech Instruments CO240 User Manual

2 CO240-en-US_v1.9 10/22
Introduction
Thank you for selecting the Extech Instruments Model CO240. The CO240 measures Carbon
Dioxide (CO
2
), Air Temperature, and Relative Humidity. It also calculates Dew Point Temperature
and Wet Bulb Temperature. The user-programmable high alarm feature alerts the user when
CO
2
level rises above the programmed limit and the data streaming feature allows readings to be
captured in real time by PC (USB connection). This device is shipped fully tested and calibrated
and, with proper use, will provide years of reliable service. Please visit our website
(www.extech.com) to check for the latest version of this User Guide, Product Updates, and
Customer Support.
Features
• Portable meter measures CO
2
, Air Temperature, and Relative humidity accurately
• Measures CO
2
(0~9,999ppm) using NDIR (Non-dispersive Infrared Technology)
• Dual display indicates Relative Humidity/Air Temperature and CO
2
• Calculates Dew Point and Wet Bulb Temperature
• Adjustable CO
2
high alarm threshold with audible beeper
• Tripod mount
• USB cable for PC data streaming
• Battery or AC Adaptor Powered

Extech Instruments CO240 Specifications

Display and Measurement

display	Dual multifunction LCD
CO2 measure range	0 to 9, 999 ppm
CO2 accuracy	± (75 ppm + 5% of reading) 0 to 2, 000 ppm

Operating Environment

operating temperature	0 to 50°C (32 to 122°F); 0.1° resolution
operating relative humidity	0 to 95% RH (avoid condensation)
relative humidity accuracy	± 5% of rdg at 25°C (77°F) otherwise ±7% RH

Temperature Ranges

dew point temperature range	‐72.9 to 47°C (‐99.22 to 118°F); 0.1° resolution
wet bulb temperature range	‐11 to 48.2°C (12.2 to 118.8°F); 0.1° resolution
temperature accuracy	± 1°C (1.8 °F)

Storage Conditions

storage temperature	‐20 to 50°C (‐4 to 122°F)
storage humidity	0 to 95% RH (avoid condensation)
dimensions	211 x 60 x 40 mm (8.3 x 2.4 x 1.6")

Power and Weight

power	AAA batteries x 6 pcs or AC adaptor
weight	181.4 g (6.4 oz.)