Teledyne gfc 7000ta operation manual Gas Flow Problems

Troubleshooting Model GFC7000TA Carbon Dioxide Analyzer

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 O2 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.

Teledyne Analytical Instruments 228