Teledyne 4020 – Hydrocarbon analyzer (special version for automatic background gas switching) - Manual (Page 78)

Operation Model 4020
Teledyne Analytical Instruments 60
To switch to the default mode of valve operation:
<▲▼> From the VALVE SELECTIONS menu, Use the <▲▼>
keys to toggle the option to default
<Enter> Press <Enter> to bring up the valve selection default
screen.
▲▼>
Use the <▲▼> keys to toggle to the “DEFAULT”
option.
<Enter> Press <Enter> when “DEFAULT” is displayed on screen.
<Escape> Use Escape to move back to the Analyze Mode. Note that
the analyzer will now switch either sample or calibration
gas (zero or span) to the analyzer depending on the
function of the analyzer, whether it is analyzing a sample
gas or calibrating.
During analysis, the screen will display as:
While in span calibration, the screen will display as:
with a similar display for a zero calibration except the zero valve will be
indicated as open (“ZERO ZEROV”).