Teledyne GFC-7000T - Trace CO2 Analyzer - manual - Manual (Page 246)

Troubleshooting Model GFC7000TA Carbon Dioxide Analyzer
Teledyne Analytical Instruments 228
10.2. Gas Flow Problems
The GFC 7000TA has two main gas flow path, the sample gas flow path and the GFC purge gas flow
path. Both are controlled by a critical flow orifice. Only the sample gas path is measured and reported.
When the IZS or zero/span valve options are installed, there are several subsidiary paths but none of
those are displayed on the front panel or stored by the DAS.
With the O
2
sensor option installed, third gas flow controlled with a critical flow orifice is added, but this
flow is not measured or reported.
In general, flow problems can be divided into three categories:
 Flow is too high
 Flow is greater than zero, but is too low, and/or unstable
 Flow is zero (no flow)
When troubleshooting flow problems, it is crucial to confirm the actual flow rate without relying on the
analyzer’s flow display. The use of an independent, external flow meter to perform a flow check as
described in Section 9.3.4 is essential. If this test shows the flow to be correct, check the pressure
sensors as described in Section 11.5.6.5.
The flow diagrams provided in this manual depicting the GFC 7000TA in its standard configuration and
with options installed can help in trouble-shooting flow problems. For your convenience they are
collected here.