Gas Analyzer Model: 6900

Primary Applications: Cylinder Fill Plants, Checking Gas Mixers

  • Analysis of most common binary industrial gas mixtures
  • Nine standard ranges are calibrated at the factory
  • Calibration only recommended once per year
  • Rugged thermal conductivity detector normally lasts the lifetime of the gas analyzer
Get a Quote


Model 6900
0-100% CO2 in Ar
0-100% O2 in Ar
0-100% He in Ar
0-100% H2 in Ar
0-100% N2 in Ar
0-100% CO2 in N2
0-100% O2 in N2
0-100% He in N2
0-100% H2 in N2
Valid over 50°F to 90°F (10°C to 32°C) ambient temperature conditions.
± 0.3% of minor component over range of 0-10.0%, all ranges.
Example: for a 5% O2 in Ar mixture, the analysis will be between 4.7 and 5.3% O2.

±0.5% of minor component over a range of 10.1% to 30.0%, all ranges.
Example: for a 25% CO2 in Ar mixture, the analysis will be between 24.5% and 25.5% CO2.

±1% of minor component over a range of 30.1% to 60.0%, all ranges.
Example: for a 50% CO2 in N2 mixture, the analysis will be between 49.0% and 51.0% CO2.

±2% of minor component over a range of 60.1% to 100.0%, all ranges, except CO2 in Ar, which has an accuracy of ±8%.
Example: for a 75% He in Ar mixture, the analysis will be between 73.0% and 77.0% He.
Operating Temperatures 40°F to 100°F (4°C to 38°C)
Resolution 0.1%
Response Time 95% in 45 seconds for typical gas mixtures
Utilities Required Reference Gas: Commercial grade argon or nitrogen (depending upon the base gas in range used) is required to flow continuously at 0.5 SCFH during analysis.
Sample Gas: Moisture and oil free sample gas is required to flow continuously at 1.0 SCFH during analysis.
Sample, reference gas pressure: 1-100 PSIG
Power: 115 VAC, 60 Hz., 1 Amp
Optional – Model 6900-100, 100 VAC, 50/60 Hz, 1 ampere
Optional – Model 6900-230, 230 VAC, 50/60 Hz, 0.5 ampere
Frequency of Calibration Calibration is recommended once per year when used under spot checking conditions; if run continuously will depend on conditions and range.
Warm Up Time 8 minutes under room temperature conditions
Dimensions and Weight 9" High, 11" Wide, 14" Deep (23 cm x 28 cm x 35.5 cm)
Weight 22 lbs. (10 kg)
Dimensions 9.0 in (23.0 cm) height, 11.0 in (28.0 cm) width, 14.0 in (35.5 cm) depth
Altitude Sea level to 2000 ft. (Altitude above 2000 ft. will cause some inaccuracy; consult the factory)
Analyzer Outputs Current: 4-20 mA, proportional to gas analysis range selected (available on all ranges). The 4-20 mA resolution equals display resolution of 0.1% gas analysis.

Additional Information

Custom Range

The user may encounter a gas mixture pair other than the nine standard ranges built into the analyzer. In this case, the user may perform an analysis by inputting his own calibration data into the analyzer. This can be accomplished by utilizing the pushbuttons on the front meter. Guidance is available from the factory concerning the thermal conductivity response of a wide variety of gas pairs.


Thermco has been providing service for their analyzers since 1951. The Thermco repair department can normally complete repairs in two weeks.


Improper use of this product can cause serious injury or property damage. Personnel dealing with this equipment should read and understand warning labels and instruction manuals provided by Thermco.

The Model 6900 is not intended to measure oxygen/nitrogen mixtures for breathing air, oxygen purity, or other medical applications.

The Model 6900 is not designed to be used with toxic gases or gases corrosive to brass or nylon.