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Calibration Procedures 
 Model GFC7000TA Carbon Dioxide Analyzer 
 
Teledyne Analytical Instruments 
161 
7. CALIBRATION PROCEDURES 
This contains a variety of information regarding the various methods for calibrating a Model GFC 7000TA 
CO
2
 Analyzer as well as other supporting information.   
NOTE 
The procedures in this assume that the calibration password feature is disabled 
(the instruments default state).  If it is enabled a password prompt screen (See 
Section 6.9) will appear after the CAL, CALZ or CALS buttons are pushed but before 
the instrument enters the associated calibration mode. 
 
7.1. Before Calibration 
The calibration procedures in this assume that the Range Type, Range Span and units of measure have 
already been selected for the analyzer.  If this has not been done, please do so before continuing (See 
Section 6.8 for instructions). 
All Gas lines should be PTFE (Teflon), FEP, glass, stainless steel or brass.   
NOTE 
If any problems occur while performing the following calibration procedures, refer 
to Section 11 of this manual for troubleshooting tips.
 
7.1.1. Zero Air and Span Gas 
To perform the following calibration you must have sources for zero air and span gas available.   
Zero Air is similar in chemical composition to the Earth’s atmosphere but scrubbed of all components that 
might affect the analyzer’s readings.  Zero air should contain less than 25 ppb of CO
2
 and other major 
interfering gases such as CO and Water Vapor.  It should have a dew point of -5
C or less 
Span Gas is a gas specifically mixed to match the chemical composition of the type of gas being 
measured at near full scale of the desired measurement range.  It is recommended that the span gas 
used have a concentration equal to 80% of the full measurement range.   
If Span Gas is sourced directly from a calibrated, pressurized tank, the gas mixture should be CO
2
 mixed 
with Zero Air or N
2
 at the required ratio. 
Zero air generators that condition ambient air by drying and removal of pollutants are available on the 
commercial market such as the Teledyne Instruments Model 701 Zero Air Generator.  We recommend 
this type of device, in conjunction with bottled N
2
 for generating zero air.