Teledyne GFC-7000T - Trace CO2 Analyzer - manual - Manual (Page 46)

Getting Started Model GFC7000TA Carbon Dioxide Analyzer
Teledyne Analytical Instruments 28
7. Attach a sample inlet line to the sample inlet port. The SAMPLE input line should not be more
than 2 meters long.
NOTE
Ideally, the pressure of the sample gas should be at ambient pressure (0 psig).
Maximum pressure of sample gas should not exceed 1.5 in-Hg over ambient.
In applications where the sample gas is received from a pressurized manifold, a vent
must be placed as shown to equalize the sample gas with ambient atmospheric
pressure before it enters the analyzer.
This vent line must be:
 At least 0.2m long
 No more than 2m long and vented outside the shelter or immediate area
surrounding the instrument.
8. Attach sources of zero air and span gas (see Figures 3-3 through 3-8 inclusive).
 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.
In the case of CO
2
measurements made with the Teledyne Instruments Model GFC 7000TA
Analyzer it is recommended that you use a gas calibrated to have a CO
2
content equaling
80% of the range of compositions being measured.
EXAMPLE: If the application is to measure between 0 ppm and 500 ppm, an appropriate Span
Gas would be 400 ppm. If the application is to measure between 0 ppm and 100 ppm, an
appropriate Span Gas would be 80 ppm.
 Span Gas can be purchased in pressurized canisters or created using Dynamic Dilution
Calibrator such as the Teledyne Instruments Model T700 and a source of dried air scrubbed
of CO
2
such as a bottle of N
2
.
 Zero Air is similar in chemical composition to the Earth’s atmosphere but scrubbed of all
components that might affect the analyzer’s readings.
In the case of CO
2
measurements this means less than 0.1 ppm of CO
2
and Water Vapor
(when dew point <-15˚C). Zero Air can be purchased in pressurized canisters.
9. Attach an exhaust line to the exhaust outlet port.
 The exhaust from the pump and vent lines should be vented to atmospheric pressure using
maximum of 10 meters of ¼” PTEF tubing.
CAUTION
Venting should be outside the shelter or immediate area surrounding the instrument.