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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 fruit storage 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. A red LED tells when to recharge and a green LED verifies that it is receiving recharging power. The recharger is included.
Unit of Measure


N/A Electrochemical O2 sensor Infrared detector for CO2

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% 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


N/A 4 to 49 ºC40 to 120 ºF


N/A ±1.0% of full scale

Size & Weight

N/A K Style: 14" L x 10 1/2" W x 6" H @ 12 lbs (36 x 27 x 15 cm @ 5.5 kg) WP Style: 10" L x 7 1/2" H x 6 1/2" D @ 8 lbs (25.5 x 19 x 26.6 cm @ 3.6 kg)


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

Output Options

N/A 0-1 VDC 4-20 mA

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.

Primary Gas to be Measured

N/A Carbon Dioxide (CO2) Oxygen (O2)

Industry Type

N/A C/A Room Monitoring


    For checking carbon dioxide (CO2) and oxygen (O2) in controlled atmosphere (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 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 flowmeter
  • Weatherproof (WP) cabinet with clear Lexan cover


  • Recorder outputs of 0-1 V or 4-20 mA
  • Sample pre-cooler for hot samples
  • Condensate removal for wet applications
  • Suitcase (K) style cabinet available
  • AC power only operation
  • CO2 and O2 alarms with LED
  • Data logger


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

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