Dual O2/CO2 Monitor, 0-25% and 0-10,000ppm

Dual O2/CO2 Monitor, 0-25% and 0-10,000ppm

Item #: 99039 (IN-STOCK)


Product Summary

PureAire Monitoring Systems’ Dual O2/CO2 Monitor is designed for continuous monitoring of oxygen and carbon dioxide in confined spaces. The monitor is ideal for facilities that use inert gases, including, but not limited to, nitrogen, helium, carbon dioxide, and argon. The Dual O2/CO2 Monitor is suitable for environments such as cryogenic facilities, breweries, food processing plants, pharmaceutical manufacturing, laboratories, hospitals, and universities. The monitor will remain accurate at temperatures as low as -40c. PureAire’s durable, non-depleting, zirconium oxide sensor cell and non-dispersive, infrared sensor (NDIR) cell, will last 10+ years in a normal environment, without needing to be replaced.



  • No scheduled maintenance zirconium O2 cell and long-life CO2 sensor
  • No calibration is required for oxygen
  • Self-calibrating CO2 sensor
  • Local backlit concentration display
  • Built-in audible horn
  • Built-in visual LED alarm indicators
  • Alarm level 1 for CO2 / Alarm 2 for O2
  • No drift due to environmental or temperature changes
  • 3-year warranty
  • 24V DC Power Supply Included (99039, 99122)
  • International Power Supply Included (99139, 99176)

PureAire Monitoring System’s Dual Oxygen/Carbon Dioxide Monitor provides continuous monitoring of oxygen and carbon dioxide. The Monitor is ideal for use in confined spaces where low oxygen concentrations could pose a health hazard, from nitrogen gas storage sites to carbon dioxide beverage gas distribution areas.

While many dual O2/CO2 monitors rely on electrochemical sensor cells, PureAire developed its Dual O2/CO2 Monitor with a zirconium oxide and NDIR cell. This cell is impermeable to changing barometric pressure, storms, temperatures, and humidity, for reliable performance across a range of atmospheric conditions. While other units require quarterly calibration and periodic maintenance, PureAire’s Dual O2/CO2 Monitor needs no scheduled maintenance or calibration once installed. If you seek a dual O2/CO2 monitor that you can plug in, leave alone, and rely on to monitor oxygen and carbon dioxide levels, try PureAire.

Sampling Method & Range Diffusion, 0-25% O2, 0-10,000ppm CO2
Accuracy Delivers ±0.2% O2 accuracy (±1% of full range- O2)
±30 ppm, ± 3% of measured value – CO2
Operating Temperature -0 to + 60° C
Display ¾” backlit LCD digital display
Sensor Type Long-life zirconium oxide sensor for O2 and NDIR for CO2
Alarm indicators Built-in Audible 90dB horn, Orange LED alarm indicator for CO2, Red LED alarm indicator for O2
Signal Outputs One user-adjustable Alarm relay for Oxygen and one user-adjustable Alarm relay for CO2. Relays are rated 2 amp 24VDC / 24VAC
Analog Output Analog 4-20mA output (Active), selectable for either Oxygen or CO2. Optional 0-5 VDC output for CO2.
Power Requirements 24VDC 350mA
Dimensions 6.5 (W) x 4.5 (H) x 3.25 (D) inches; (165.1 mm x 114.3 mm x 82.5 mm)
Weight 1.6 lbs. (.8 kg)
Enclosure Polycarbonate
Required calibration  Calibration is not required for Oxygen. None for CO2 when Auto Cal function is activated. Periodic span adjustment as needed for Oxygen.
Country of Origin USA
Harmonized Tariff Code 8531.10.0045
Additional O2 Monitor Accessories List Price
8 Channel Controller $3,355.00 US (P/N # 99196)
Horn and Strobe  $190.00 US (P/N # 42002)
Remote Display $435.00 US (P/N # 99183)

No Calibration Required

Unlike other oxygen monitors, PureAire’s Dual O2/CO2 Monitor does not require quarterly calibration. The earth provides calibrated oxygen to challenge the Dual O2/CO2 Monitor to 20.9 percent oxygen and 400 ppm CO2 under ambient conditions. On a weekly basis, the monitor automatically recalibrates to the ambient CO2 level for reliable performance. Once installed, the monitor needs no adjustments and no scheduled maintenance for truly maintenance-free O2/CO2 detection.

Plug & Play Setup

PureAire’s Dual O2/CO2 Monitor is ready to work the moment you take it out of the box and mount it. All you need to do is remove the unit, mount it to a wall or another surface, and connect the power supply to a socket. The monitor takes four minutes to start up, then begins operating automatically. Once set up, the Dual O2/CO2 Monitor provides non-stop leak detection for years. Our bumper-to-bumper warranty makes the Dual O2/CO2 Monitor the last monitor you’ll ever need to purchase.

PureAire’s Dual O2/CO2 Monitor Installations

PureAire’s Dual O2/CO2 Monitor is ideal for a range of installations. Place one in restaurants, fast food outlets, bars, and anywhere that N2 and CO2 are used to dispense carbonated beverages. Or use it in an agricultural grow room, laboratory, or other places where inert gases could pose a health hazard if a leak occurs. PureAire’s Dual O2/CO2 Monitor never drifts or loses sensitivity when weather, barometric pressure, or temperature changes, so you can rely on it to work properly at all times.

Dual O2/CO2 Monitor Control Features

PureAire’s Dual O2/CO2 Monitor comes with user-selectable relays that connect to on-off valves, which control CO2 injection and simultaneously activate alarms when oxygen levels fall below the OSHA threshold. The oxygen sensor can also check carbon dioxide levels and control nitrogen generators in hypobaric rooms. PureAire’s Dual O2/CO2 Monitor features an inexpensive monitor that has a local display, separate controls for oxygen and carbon dioxide, safety alarms, and a built-in CPU.

Dual O2/CO2 Literatthumbnail of 99039 Dual O2 CO2 Monitorure

99039/99139 – PureAire Dual O2 / CO2 Monitor Manual

99122/99176 – PureAire Dual O2/CO2 Monitor Manual

Safety Risks of Oxygen Deficiency

Carbon Dioxide Safety

Comparison of annual maintenance

Oxygen Monitor Sales Presentation

Remote Digital Display p/n 99183

Horn/strobe 24VDC Red

horn and strobe


8-Channel Programmable Controller for Oxygen, Carbon Dioxide, or Toxic/Combustible Gas Monitors