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Teledyne API Model 200AU NO
X
Analyzer Instruction Manual, 02293, Rev. F
7-22
2. Turn on and adjust the O
3
generator in the calibrator to produce sufficient O
3
to decrease
the NO concentration to about 10% of full scale. This will be equivalent to 80% of the URL
of the NO
2
channel. After the analyzer responses stabilize, record the resultant NO, NO
x
, and
NO
2
concentrations.
MOLY CONVERTER EFFICIENCY
IF THE NO
X
READING SHOULD DROP TO LESS THAN 96% OF ITS STARTING
VALUE DURING THIS STEP, IT INDICATES THE MOLY CONVERTER IS IN NEED
OF TROUBLESHOOTING OR REPLACEMENT. SEE SECTION 7.6.6 FOR FURTHER
DETAILS.
3. While maintaining all other conditions, adjust the ozone generator to obtain several other
concentrations of NO
2
evenly spaced between the 80% URL point and the zero point. Record
the NO, NO
x
, and NO
2
concentrations for each additional point.
4. Calculate the resulting NO
2
concentrations as follows:
[
NO
]
= [NO
]
- [NO
]
+
F
*[
NO
]
F
Equation - 10
2
OUT ORIG REM
NO 2
IMP
T
7
Where:
[NO]
ORIG
is the NO concentration before the GPT ozone is turned on, and [NO]
REM
is the NO
remaining after GPT.
5. Plot the NO
2
concentration output by the instrument on the y-axis against the generated
NO
2
[NO
2
]
OUT
on the x-axis. The plot should be a straight line within the
±
2% linearity
criteria given for the NO
x
and NO channels. If the plot is not linear the most likely cause is
that the converter needs replacing. See Section 7.6.6 on Moly converter efficiency.