083730510A DCN8172
Teledyne API T500U CAPS NO
2
Analyzer with NumaView™ Software
99
LED
COLOR
FUNCTION
INDICATED FAILURE(S)
D12
3
Green
Pressurized Span shutoff valve
Valve broken or stuck, valve driver chip broken
D13
4
Green
Pressurized Zero shutoff valve
Valve broken or stuck, valve driver chip broken
1
Only active when the optional internal span gas generator is installed.
2
Only active when the dual pressurized span option is installed.
3
Only active when one of the pressurized span gas options is installed.
4
Only active when one of the pressurized zero gas options is installed.
Note: D4, D6, and D14-16 are not indicated as they are not used.
C
ALIBRATION
P
ROBLEMS
This section describes possible causes of calibration problems.
NEGATIVE CONCENTRATIONS
Negative concentration values can be caused calibration error: If the zero air were
contaminated, and the analyzer was calibrated at “zero”, the analyzer may report a negative
value when measuring air that contains little or no NO
2
.
ABSENCE OF ANALYZER RESPONSE TO SAMPLE GAS
If the instrument shows no response (display value is near zero) even though sample gas is
supplied properly and the instrument seems to perform correctly
:
1. Confirm the lack of response by supplying or NO
2
span gas of about 80% of the
range value to the analyzer.
2. Check the sample flow rate for proper value.
3. Check for disconnected cables to the sensor module.
UNSTABLE ZERO AND SPAN
Leaks in the instrument or in the external gas supply and vacuum systems are the most
common source of unstable and non-repeatable concentration readings.
1. Check for leaks in the pneumatic systems as described in Section 5.6.5.
2. Consider pneumatic components in the gas delivery system outside the analyzer
such as a change in zero air source (ambient air leaking into zero air line) or a change
in the span gas concentration due to zero air or ambient air leaking into the span gas
line.
3. Once the instrument passes a leak check, do a flow check (this chapter) to ensure
that the instrument is supplied with adequate sample and ozone air.
4. Confirm the sample pressure, sample temperature, and sample flow readings are
correct and steady.
5. Verify that the sample filter element is clean and does not need to be replaced.
Summary of Contents for T500U
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