• CO2: 0 to 5,000ppm
• Temperature: 14 to 140°F (-10 to 60°C)
• Humidity: 0.0 to 99.9%

The Extech CO250 measures CO2 (Carbon Dioxide) levels, air temperature, dew point, wet bulb, and humidity and is an ideal instrument for indoor air quality (IAQ) diagnosis. This meter is shipped fully tested and calibrated and, with proper use, will provide years of reliable service.

Taking measurements

The meter starts measurements when powered on and updates readings every second. If the operating environment changes (ex. from high to low temp.), it takes 30 seconds for CO2 sensor to respond and 30 minutes for RH.

NOTE: Do not hold the meter close to your mouth or any other source of CO2.

In the MIN and MAX modes, the meter shows the minimum and maximum readings of CO2 (main display), air, dew point or wet bulb temperatures (lower left display) and humidity (lower right display).

In STEL (short term exposure limit) and TWA (time weighted average) modes, the main display shows the weighted average of CO2 readings for the past 15 minutes (STEL) or 8 hours (TWA). The lower displays are the current measurements.

Alarm

The meter features an audible alarm to give warnings when CO2 concentration exceeds the set limit. It emits beeps (approximately 80dB) when CO2 level goes over the set value and stops when any key (except SET) is pressed or the readings fall below the set value. It beeps again if the value exceeds the limit.

PC connection

The meter is equipped with an RS-232 PC interface jack (3.5mm phono) for connection to a PC. The supplied cable and Windows compatible software allows the user to store readings in a text file and display real-time measurements in a series of selectable formats.

1. Temperature and Humidity sensor

2. CO2 sensor (rear)

3. LCD display

4. AC Adaptor connector

5. RS232 port

6. Keypad

7. Battery compartment (rear)