CDM775355-final-092508:Layout 1 9/25/08 CDM77535 USER’S MANUAL Digital CO2 Environmental Meter INTRODUCTION Thank you for purchasing this portable CO2 meter. The meter measures CO2 level, air temperature, dew point, wet bulb temperature and humidity and is an ideal instrument for indoor air quality (IAQ) diagnosis.
CDM775355-final-092508:Layout 1 9/25/08 Poor indoor air quality is considered unhealthy because it causes tiredness, loss of ability to concentrate, and even illness (ex. Sick Building Syndrome). IAQ monitoring and survey, especially on CO2 level and air ventilation, has become widely applied in public areas such as offices, classrooms, factories, hospitals and hotels. It is also used in the regulations of industrial hygiene in some countries.
CDM775355-final-092508:Layout 1 9/25/08 LCD DISPLAY SYMBOLS TWA . . . . . . . . . . Time weighted average (8 hours) STEL . . . . . . . . . . Short-term exposure limit (15 minutes weighted average) HOLD . . . . . . . . . Readings are frozen unchanged MIN/MAX . . . . . . Minimum/Maximum readings (ICON) . . . . . . . . Low battery indicator DP . . . . . . . . . . . Dew point temperature AIR . . . . . . . . . . . Air temperature WBT . . . . . . . . . . Wet bulb temperature % . . . . . . . . . . .
CDM775355-final-092508:Layout 1 9/25/08 OPERATION POWER ON/OFF Press ( ) to turn the meter on and off. At power up, it emits a short beep and performs 30 seconds count down (Fig. 2) for meter warm up, then enters normal mode with current CO2, temperatures, and humidity readings displayed (Fig. 3). TAKING MEASUREMENT The meter starts measurement when powered on and updates readings every second. In the condition of operating environment change (ex.
CDM775355-final-092508:Layout 1 9/25/08 BACKLIGHT Hold down ( ) for more than 1 second to activate and cancel backlight function. MIN, MAX, STEL, TWA Under normal mode, press ( ) to see the minimum, maximum, and weighted average readings. Each press of ( ) displays MIN, MAX, STEL, and TWA in sequence and returns to normal mode. In MIN and MAX modes, it shows the minimum and maximum readings of CO2 on main display and of AIR or DP or WB temperatures and humidity on the lower displays. (Fig.
CDM775355-final-092508:Layout 1 9/25/08 ALARM The meter features an audible alarm to give warnings when CO2 concentration exceeds the limit. (See P1.o in setup for setting alarm threshold). It emits beeps (Abt.80dB) when CO2 level goes over the set value and stops when any key (except ) was pressed or readings fall below the set value. It beeps again when value goes over the limit. Restart the meter if beeper can't be stopped.
CDM775355-final-092508:Layout 1 9/25/08 PROGRAMMING P3.o TEMPERATURE SCALE Press ( ) or ( ) in P1.o to access P3.o for setting up temperature scale (Fig. 12). Press ( ) and it goes into P3.1 with blinking °C or °F current set (Fig.13) on the lower left display. To switch °C or °F, Press ( ) and ( ). Then press ( ) to save the setting or ( ) without saving and return to P3.o. CO2 CALIBRATION The meter defaults to be calibrated manually in the ambient air where CO2 concentration is around 400ppm.
CDM775355-final-092508:Layout 1 9/25/08 RH CALIBRATION The meter defaults to have the humidity calibrated with 33% and 75% salt solution. The ambient condition is recommended to be at 77°F (25°C) and stable humidity (better to be close to the calibrating value). To abort calibration, just turn off the meter. CAUTION: Do not calibrate the humidity without the default calibration salt. Otherwise, it will cause permanent damage. Contact the dealer for calibration salts.
CDM775355-final-092508:Layout 1 9/25/08 TROUBLESHOOTING ? CAN’T POWER ON Press ( ) for more than 0.3 seconds and try again. Check whether batteries are in good contact with correct polarity, or the adapter is plugged in properly. ? FIXED READINGS Check whether data hold function was activated. (HOLD icon at the top left) ? SLOW RESPONSE Check whether the airflow channels on the rear are blocked.
CDM775355-final-092508:Layout 1 SPECIFICATION CO2 Range: Resolution: Accuracy: Pressure Dependence: TEMPERATURE Range: Resolution: Accuracy: HUMIDITY Range: Resolution: Accuracy: Warm up: Operating: Storage: Power Source: Battery life: 9/25/08 0-5,000ppm 5,001-9,999 (out of scale) 1ppm ±50ppm ±5%rdg (0-5,000ppm) Not specified for out-of-scale +1.6% reading per kPa deviation from normal pressure, 100kPa 14º-140°F (-10.0º to 60.0°C) 0.1°F (0.1°C) ±0.9°F (0.6°C) 0.0 to 99.9% 0.
CDM775355-final-092508:Layout 1 Type 1 Type 2 9/25/08 Indoor areas such as department stores, theaters, restaurants, libraries, the acceptable CO2 concentration of 8 hours average is 1,000ppm. Indoor areas with special requirements of good air quality such as schools, hospitals, day care centers, the suggested CO2 level is 600ppm. REGULATORY EXPOSURE LIMIT ASHRAE Standard 62-1989: 1,000ppm CO2 concentration in occupied building should not exceed 1,000ppm.
CDM775355-final-092508:Layout 1 9/25/08 GENERAL TOOLS & INSTRUMENTS™ 80 White Street, New York, NY 10013-3567 PHONE (212) 431-6100 FAX (212) 431-6499 TOLL FREE (800) 697-8665 e-mail: sales@generaltools.com www.generaltools.com CDM77535 User’s Manual Specifications subject to change without notice ©2008 GENERAL TOOLS & INSTRUMENTS™ NOTICE - WE ARE NOT RESPONSIBLE FOR TYPOGRAPHICAL ERRORS.
