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The Model 309A Series Portable CO2 and O2 analyzer is a rugged, fast-responding and accurate instrument for conveniently monitoring the atmosphere in a fruitstorage C/A room. The standard range of the analyzer is 0-10% CO2 and 0-25% O2. Other ranges are available.

The Model 309A Series utilizes a single cell infrared detector for CO2 and a customer replaceable electrochemical sensor for O2. Neither sensor is affected by water vapor or other gas vapors in the sample gas. The O2 sensor typically lasts 3-4 years.

In operation, a built-in sample pump draws in the gas sample through the sample hose, filter/condensate trap, secondary filter and flow meter then on to the CO2 and O2 detectors. The gas readings are then displayed on LCD digital meters which have switchable backlights for use in dark areas.

A rechargeable battery provides enough power for about 8 hours of continuous operation and the analyzer can be used while it is being recharged. The recharger is included.
Unit of Measure


Method of Detection

N/A Infrared detector for CO2 Long life electrochemical O2 sensor

Ranges Available

N/A 0-25% O2 (Other ranges available) 0-3000 PPM; 0-5000 PPM; 0-1%; 0-10%; 0-20%; 0-50%; 0-100% CO2


N/A 0.1% on % versions or 10 PPM on PPM versions

Accuracy & Repeatability

N/A Within ±2% full scale


N/A Within 1% of full scale per 8 hours of continuous operation

Response Time (T-90)

N/A O2 less than 10 seconds; CO2 less than 30-40 seconds to T-90

Ambient Temperature Range

N/A 4 to 49 ºC40 to 120 ºF


N/A Within ±1% of full scale

Size & Weight

N/A 11 1/2" L x 8" W x 7 1/4" H


N/A AC/DC Operation, 115 VAC, 60 Hz for recharging

Output Options

N/A 0-1 VDC 4-20 mA



    For checking carbon dioxide (CO2) and oxygen (O2) in controlled atmoshpere (C/A) storage rooms, welding gas mixtures and other process applications.



  • Rugged design that is easy to operate
  • Fast warm-up and response
  • Solid state infrared detector for CO2
  • Long-life electrochemical sensor for O2
  • Digital readout meter with backlight
  • Modular layout that is easy to maintain
  • REchargeable battery operation
  • Stainless steel probe with sample hose
  • Built-in sample pump, filter and flow meter
  • Weatherproof (WP) cabinet with clear Lexan cover



  • Recorder outputs of 0-1V or 4-20mA
  • Sample pre-cooler for hot samples
  • Condensate removal for wet applications
  • Suitcase (K) or bench top (BT) style cabinets available
  • AC power only operation
  • CO2 and O2 alarms with LED
  • Detachable/portable datalogger



  • Air for CO2 zero and O2 span
  • Analyzed calibration gas for CO2 span and O2 zero

Unique Applications


    All Nova analyzers are built using proven technologies and techniques. If this product does not suit your application, please contact Nova. In many cases, we are able to build an analyzer specific to your needs.

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