Subsystem Check For Troubleshooting - Teledyne T200 User Manual

If the valve is operating properly, you should be able to hear it switch (once a
•
minute under normal operation or when manually activated from the
Utilities>Diagnostics>Digital Outputs menu):
If the PMT value drops significantly but not to less than 150 mV, the valve is
•
probably leaking across its ports.
• If the PMT value does not change at all, the valve is probably not switching at all.
Note
Another reason for high (although not necessarily out-of-range) values for Auto Zero could
be the ozone air filter cartridge, if its contents have been exhausted and must be replaced.
This filter cartridge chemicals that can cause chemiluminescence and, if saturated,
•
these chemicals can break through to the reaction cell, causing an erroneously high
Auto Zero value (background noise).
A dirty reaction cell can cause high Auto Zero values.
Clean the reaction cell according to Section 5.6.8.
•
Finally, a high HVPS voltage value may cause excess background noise and a high Auto
Zero value.
The HVPS value changes from analyzer to analyzer and could show nominal values
•
between 450 and 800 V.
Check the low-level hardware calibration of the preamplifier board and, if necessary,
•
recalibrate exactly as described in Section 5.7.10.4 in order to minimize the HVPS.
S
UBSYSTEM
The preceding sections of this manual discussed a variety of methods for identifying
possible sources of failures or performance problems within the analyzer. In most cases
this included a list of possible causes and, in some cases, quick solutions or at least a pointer
to the appropriate sections describing them. This section describes how to determine if a
certain component or subsystem is actually the cause of the problem being investigated.
083730200A DCN7962
• the PMT value should drop from span gas reading (e.g., 800-900 mV at
400 ppb NO) to less than 150 mV and;
• the LED on the relay board should light up when the valve is activated.
In this case, replace the valve.
•
Check the power supply to the valve (12 V to the valve should turn on
•
and off when measured with a voltmeter).
It takes only a small leak across the ports of the valve to show
excessive Auto Zero values when supplying high concentrations
of span gas.
C T
HECK FOR ROUBLESHOOTING
Teledyne API T200 NO/NO /NO Analyzer with NumaView™ Software
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