Teledyne API Model 200A NOX Analyzer Instruction Manual, 02246, Rev. G, DCN 5247
9.3.9 Z/S Valves & IZS Permeation Tube Oven
The Z/S Valves and IZS are both options in the instrument. Before troubleshooting this sub-
assembly, check that the options were ordered, and that they are enabled in the software.
Sections 7.2, 7.3 show how the Z/S valve and IZS options should be set-up, and how to use them
with the AutoCal and Dynamic Cal features.
Check for the Z/S valves:
1. Check for the physical presence of the valves. See Table 2-2-5 for the Z/S Valve
location.
2. Check front panel for option presence. The front panel display when the instrument is in
SAMPLE mode should display CALS and CALZ buttons on the second line of the display.
The presence of the buttons indicates that the option has been enabled in software.
Troubleshooting the Z/S valves:
1. It is possible to manually toggle each of the valves using the SIGNAL I/O selection of
DIAGNOSTIC mode. Refer to Section 9.1.3 for information on using the DIAG mode. Also
refer to Table 8-8-6, Table 8-8-7, Table 8-8-8 for a pneumatic diagram of the system.
Check for the IZS option:
1. Check for the physical presence of the IZS oven. See Table 2-2-5 for the Z/S Valve
location.
2. Check front panel TEST functions for presence of IZS temperature. If IZS temperature is
displayed, the IZS oven temperature control algorithm and temperature display has been
enabled in the software.
Accuracy and Repeatability of NO2 permeation tube.
The PTFE membrane of the permeation tube is affected by humidity. If the instrument is
installed in an air conditioned shelter, the air is usually dry enough to produce good results. If the
instrument is installed in a non-climate controlled site that has high humidity, variations in the
perm tube output will occur. For these sites, if high accuracy is required an additional source of
dry (dewpoint of -20 C or less) air, such as the M701 zero air module, should be attached to the
zero air scrubber inlet.
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