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The Nova 7900 Series Heat Treat Analyzers are designed for the continuous monitoring of various combinations of gases such as oxygen (O2), methane (CH4), carbon dioxide (CO2), carbon monoxide (CO), and hydrogen (H2) for industrial processes including heat treating atmospheres.

Standard Cabinet: Wall Mounted NEMA4 (IP65) Enclosure Rating

Detection Technologies:
O2 - long-life electrochemical sensor
CO - non-consumable, long-life infrared detector
CO2 - non-consumable, long-life infrared detector
CH4 - non-consumable, long-life infrared hydrocarbons detector
H2 - non-consumable, long-life thermal conductivity cell; available with internal compensation for interference effects from CO, CO2, and CH4

Model 7902D: O2 and CO2

Unit of Measure


Method of Detection

N/A Electrochemical sensor for O2; NDIR infrared detector for CO

Ranges Available

N/A 0 - 2,000 PPM to 0 - 25.0% O2; 0 - 1.00%, 0 - 50.0% CO2


N/A 0.1%, 10 PPM

Accuracy & Repeatability

N/A ±1% of full scale on all gases


N/A Less than 2% of full scale per month

Response Time (T-90)

N/A 20-30 seconds to 90% step change

Ambient Temperature Range

N/A 32 to 122°F (0 to 50°C), Lower temperatures (-5°F, -20°C) with Cold Weather Package


N/A ±1% of full scale

Size & Weight

N/A Physical data will vary depending on model and enclosure required


N/A 115 VAC, 60 Hz 220 VAC, 50 Hz

Output Options

N/A 4-20 mA into 500 ohms non-isolated standard Isolated 4-20 mA, RS232, RS485, MODBUS, Ethernet outputs


N/A High and/or low alarm contacts available, relay contacts SPDT 5A @ 220 VAC rating Low flow alarm

Analyzer Type

N/A O2 and CO2 Analyzer

Hazardous Area Rating Options

N/A General Purpose, Non-Hazardous



    For continuous monitoring of any combination of heat treat atmosphere gases such as Oxygen (O2), Methane (CH4), Carbon Dioxide (CO2), Carbon Monoxide (CO), Hydrogen (H2), Ammonia (NH3), and Dew Point (standard and low ranges). Also available for other industrial process gases.



  • Best value multi-gas analyzer including hydrogen
  • Sensitive infrared detectors for CO, CO2, CH4, and NH3 temperature controlled where necessary to reduce drift
  • Thermal conductivity detector for hydrogen
  • Long life (2-5 years) electrochemical oxygen sensor, PPM and % ranges available
  • Dielectric ceramic sensor for standard or low range dew point
  • Bright digital display for each gas
  • Built in sample pump or pressure regulator
  • Microprocessor for push button calibration
  • Easy to maintain modular layout



  • Hi/Low gas, low flow, and diagnostic alarms available
  • Isolated analog, RS232, RS485, MODBUS, and Ethernet outputs available
  • Sample conditioning systems available for removal of moisture, acidic gas, and dust
  • Cabinet purge system available for use in hazardous areas
  • One-step 'cal-now' button with touch screen LCD display
  • Full automatic calibration with touch screen LCD display
  • Cold weather package for operation to -5°F (-20°C)
  • Cabinet coolers can be fitted to most models
  • High temperature filters and probes
  • Sensors mounted in temperature controlled heated box to improve accuracy



  • Ambient air for O2 span and other gases zero
  • Analyzed calibration gas with representative concentrations of non-O2 gases for span

Unique Applications


    Special models of the 7900 Series analyzers can be supplied with options such as free standing cabinets, built-in moisture removal systems, cabinet coolers, controllers, hi/low alarms, low flow alarm, 4-20 mA outputs, recorders, etc. 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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