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CO250-EU V1.2 6/09

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CO

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Levels and Guidelines

Non-Enforced Reference levels:

250 - 350 ppm – background (normal) outdoor air level
350- 1,000 ppm - typical level found in occupied spaces with good air exchange.
1,000 – 2,000 ppm - level associated with complaints of drowsiness and poor air.
2,000 – 5,000 ppm – level associated with headaches, sleepiness, and stagnant,

stale, stuffy air. Poor concentration, loss of attention, increased heart rate and

slight nausea may also be present.
>5,000 ppm – Exposure may lead to serious oxygen deprivation resulting in

permanent brain damage, coma and even death.

Regulatory exposure limits:

ASHRAE Standard 62-1989: 1000ppm: CO

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concentration in occupied building should

not exceed 1000ppm.
OSHA: 5000ppm: Time weighted average over five 8-hour work days should not

exceed 5000ppm
Building bulletin 101 (Bb101): 1500ppm. UK standards for schools say that CO

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at

averaged over the whole day(i.e. 9am to 3.30 pm) should not exceed 1500ppm.
Germany, Japan, Australia, UK...: 5000ppm, 8 hours weighted average in

occupational exposure limit is 5000ppm.

HT30-EU-EN-V3.2--9/11 

Phone: 01235 838 555

E-mail: [email protected]

web: www.airconcern.co.uk

Air Concern Ltd, Building 173 Curie Avenue Harwell Didcot, Oxfordshire OX11 0QG

more info for 

Extech CO250

Summary of Contents for CO250

Page 1: ... Model CO250 Meter This meter measures CO2 Carbon Dioxide levels air temp dew point wet bulb temperature 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 ...

Page 2: ...g on display MIN MAX Minimum Maximun readings Low battery indicator DP Dew point temperature AIR Air temperature WBT Wet bulb temperature Unit of relative humidity C or F Celsius Fahrenheit KEYPAD Turns the meter on and off Enters setup mode Sets as non sleep mode with Exits setup page mode Enters CO2 calibration with Enters RH calibration with Freezes the current reading on display Cancels data h...

Page 3: ...tors at collection points in your community or wherever batteries accumulators are sold Disposal Follow the valid legal stipulations in respect of the disposal of the device at the end of its lifecycle POWER ON OFF Press to turn the meter on and off At power up the meter emits a short beep and performs a 30 second countdown for meter warm up It then enters the normal operation mode with current CO...

Page 4: ...en since power on As well the TWA mode will display a weighted average of readings prior to 8 hours of operation 2 The CO250 takes at least 5 minutes to calculate STEL and TWA The display shows during the first 5 minutes from power on 3 The STEL and TWA values will keep updating every 5 minutes ALARM The meter features an audible alarm to give warnings when CO2 concentration exceeds the set limit ...

Page 5: ...DP WBT button to decrease the value Each press adjusts 100 ppm The alarm range is from 100 to 9900ppm When the preferred alarm value is set press the MN AV button to exit and save the setting or the CAL Esc button to exit without saving and return to P1 0 P3 0 TEMPERATURE SCALE Press the MODE button or the DP WBT button in P1 0 to access P3 0 for setting the temperature scale Press the MN AV butto...

Page 6: ...t bottle 2 In the normal mode Press and Hold the CAL Esc and DP WBT buttons to enter the 33 calibration CAL and calibrating value 32 7 if at 25 C will blink on the LCD with current temperature at the left 3 The meter is now calibrating and will finish in about 60 minutes when CAL and humidity stop blinking 75 calibration 1 After the 33 calibration plug the sensor probe into a 75 salt bottle 2 Pres...

Page 7: ... 5 to 60 C 23 to 140 F 0 1 Calculated from RH and Temperature Dew Point 20 to 60 C 4 to 140 F 0 1 Display Triple LCD with backlight Sensor Type CO2 NDIR non dispersive infrared technology Humidity Capacitance sensor Temperature air Thermistor Operating Conditions 0 to 50o C 32 to 122o F 95 RH non condensing Storage Conditions 20 to 60o C 4 to 140o F 99 RH non condensing Power Supply 4 x 1 5V AA ba...

Page 8: ...ore than 0 3 seconds and try again Check that the batteries have good contact and the correct polarity or that the AC adaptor is properly connected Slow response Check whether the air flow channels on the rear of the meter are blocked Error messages E01 CO2 sensor damaged E02 The value is under range E03 The value is over range E04 The original data error results in this error DP WB E07 Too low vo...

Page 9: ... resulting in permanent brain damage coma and even death Regulatory exposure limits ASHRAE Standard 62 1989 1000ppm CO2 concentration in occupied building should not exceed 1000ppm OSHA 5000ppm Time weighted average over five 8 hour work days should not exceed 5000ppm Building bulletin 101 Bb101 1500ppm UK standards for schools say that CO2 at averaged over the whole day i e 9am to 3 30 pm should ...

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