Teledyne GFC-7000T - Trace CO2 Analyzer - manual - Manual (Page 255)

Troubleshooting Model GFC7000TA Carbon Dioxide Analyzer
Teledyne Analytical Instruments 237
10.3.4. Inability to Zero – Touchscreen ZERO Button Not Visible
1. Confirm that there is a good source of zero air. Dilute a tank of span gas with the same amount
of zero air from two different sources. If the CO
2
Concentration of the two measurements is
different, there is a problem with one of the sources of zero air.
2. Check for leaks in the pneumatic systems as described in Section 9.3.3.
3. If the analyzer has had zero/span valve options 52 or 53, the CO
2
scrubber may need
maintenance.
4. Check to make sure that there is no ambient air leaking into zero air line.