The AOX2 Combustion Check Accessory measures percent oxygen (%O2) and flue temperature and calculates percent carbon dioxide (%CO2). The AOX2 is an affordable alternative to full-function combustion analyzers. It's designed for techs who want to do everyday combustion testing and tuning, without paying for all of the costly extras found on combustion analyzers - extras they don't need or care about.

The AOX2 allows you to easily calibrate combustion equipment such as boilers or furnaces to the manufacturer's specified % CO2, or % O2. Tuning the CO2, O2 stack temperature and temperature rise to match the appliance manufacturer's specifications will increase efficiency and help maximize performance and life expectancy of the equipment. Tuning typically involves adjusting the air/fuel ratio.

How Does It Work?
The AOX2 measures flue gas %O2 and temperature. From these measurements, it calculates and displays % CO2. Most manufacturers include targets for these parameters on the data plate or in the technical specifications.

For example, while the heating appliance (furnace, boiler, heating stove, etc.) is in operation:

1. The technician taps into the flue and inserts the probe tip with the hi-temp thermocouple installed as directed in the AOX2 operator's manual.
2. He uses the hand pump to sample the flue gas until the measurements become stable.
3. He presses the H/MAX/MIN button to toggle between a real time reading, a held reading, the maximum reading, or the minimum reading for each test parameter.
4. He adjusts the system to match manufacturer's specifications.

Features and Benefits
  • Works with any expandable Fieldpiece meter or any meter with mVDC ranges using Fieldpiece's detachable leads
  • Measurements for most common fuel types - Gas and Oil
  • Simple operation
  • Gives you the tests you're looking for to get the job done quickly and efficiently
  • Doesn't include a lot of extra tests, calculations and buttons you don't need and that get in the way
  • Fraction of the cost of full-function combustion analyzers
  • Comes with everything you need to measure against manufacturer's specs. No extras to buy.
  • APO (Auto power off)
  • Thermocouple calibration pot on front-face of meter for quick adjustments
  • Quick and easy filter replacement on included AOXP2 hand pump

Competitive Advantages

The following are competitive advantages over full-function combustion analyzers:
  • Includes the tests technicians care about without all of the extra tests they don't
  • Less than 1/2 the cost of the lowest price brand-name combustion analyzer (based on internet shopping)
  • Intuitive interface. A fancy way of saying easy to use. You can probably pick it up and use it without a 40 page instruction manual. (Of course, please read the two page operator's manual before use.)
  • Fewer button, calculations, and tests to cycle through. Gives you exactly what you need to get the job done and get to the next call
  • Hand sampling pump less prone to breakdown than electronic pumps that come with most combustion analyzers
  • No batteries on the pump to replace
  • Hand pump works much better in cold weather than most electronic pumps
  • Sensor lasts more than two years in testing (with proper filter replacement)
  • Replacement parts and everything you need to do the job are included with the meter. No extras to buy.

What's Included
  • Combustion Check meter (AOX2)
  • Flue aspirator pump (AOXP2)
  • Hi-temp k-type thermocouple -58°F -1000°F range (ATBF1)
  • Filter accessory kit (RAOX9)
  • 9V Alkaline battery (installed)
  • Operator's manual

For additional technical specifications, please see "User Guide" in the manuals tab above.
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Manuals (2)
Operating Environment:
32°F to 122°F at <75% RH
Combustion Check Accessory
Battery Life:
85 hours typical (alkaline). No measurable current draw when in "off" position
Battery Type:
15 minutes
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