NO3/NH4 Response
Check/ Adjustment
Purpose: The NO3/NH4 response check/ adjustment is to
assure that the NO3/NH4 analyzer has the correct gas calibration. This can be accomplished by introducing a
known quantity of gas to the inlet and checking the response on the
instrument. The terminology for this
type of check is GRC (Gas Replacement Calibration). Each GRC has a RF (Response Factor). This RF value should be 1.000.
Required Equipment: Precision flat head screwdriver
Reference: SOPMAN Pages XX-XX
Analyzer Setup
1.
The Background
(BKG) and Coefficient (COEF) on the analyzer should be set to 0.0 and 1.000
respectively.
2.
On the “S” model
analyzers, use the STAT button to check the BKG and COEF. The parameters are as follows: b0. = 0.00, b1. = 0.00, b3. =0.00, S.F.
=1.000 & B.F. =1.000. Push
the STAT button until each of the parameters has been checked. Push
run or auto when finished.
3.
On the “C” or
“CTL” model analyzers push “Menu” and scroll to “Calibration Factors” and press
“Enter”. At this location, the
parameters should be set as follows: Pre
BKG PPB =0.0, NO BKG PPB= 0.0, NOx BKG PPB =0.0, NO COEF =1.000, NOx COEF
=1.000 & NO2 COEF =1.000. Push run when
finished.
Analyzer Response Check
1.
Open the Gas
Calibration Worksheet and enter the correct NO concentration (found on the gas
cylinder) in the blank provided.
2.
On DataView
screen go to the Tools tab and select Trigger Cals.
3.
In the Trigger Cals
menu select NO3 Zero and press Start Calibration.
4.
Under the tools
tab select Query 1-Minute Data.
5.
In the query data
tool menu select the Air MFC and Gas MFC.
The CH1, CH2 and CH3 data is averaged constantly on the top right of
DataView.
6.
Wait 7-10 minutes
or until the data for CH1, CH2 and CH3 are stable. Press Get Data on the query data tool.
7.
Enter the Air MFC,
CH1, CH2 and CH3 data in the appropriate blank for the NO3 Zero on the Gas
Calibration Worksheet in the As Found section.
8.
Go to Trigger Cals
and push Stop Calibration then select NO3 NO GRC Point 1 and press Start Calibration.
9.
Wait 7-10 minutes
or until the data for CH1, CH2 and CH3 are stable then press Get Data.
10.
Enter the Air
MFC, Gas MFC, CH1, CH2 and CH3 data in the appropriate blanks for the NO3 NO
GRC Point 1 on the Gas Calibration Worksheet in the As Found section.
11.
The RF is now
displayed at the far right of the worksheet.
If the RF is between 0.98 and 1.02, the calibration check is complete. Close the Trigger Cals and Query Data
windows.
12.
Save the Gas
calibration worksheet then print the NO3/NH4 information and fax it to
13.
If the RF is not
within spec continue with the Analyzer Response Adjustment procedure.
Analyzer Response Adjustment
1.
Enter the as
found data for NO3 Zero in the as left section for NO3 Zero.
2.
On DataView go to
the Tools tab and select Trigger Cals.
3.
In the trigger
cals menu select NO3 NO GRC Point 1 and press Start Calibration.
4.
Under the tools
tab select Query 1-Minute Data.
5.
In the query data
tool menu select the Air MFC, Gas MFC, CH1, CH2 and CH3.
6.
Wait 7-10 minutes
or until the data for CH1, CH2 and CH3 are stable.
7.
Adjust the
instrument to the Actual Expected value from the As Found section of the
worksheet.
a.
On “C” or “CTL”
class analyzers the PMT can be adjusted by taking the top off of the
analyzer. With the top of the analyzer
off look on the right side of the bulkhead at the front. There is a blue box with an orange grommet on
the top. Inside the grommet is the PMT
adjustment screw. Some CTL model analyzers
have been modified so that the PMT can be adjusted through the front
panel. Adjust the analyzer until the NO
channel on the analyzer or CH1 on DataView is approximately equal to the Actual
Expected value from the As Found section worksheet.
b.
On “S” class
analyzers open the front door on the analyzer and adjust the PMT screw until
channel one on the analyzer or CH1 on DataView is approximately equal to the
Actual Expected value from the As Found section worksheet.
8.
When the analyzer
adjustments are complete, let the analyzer stabilize for 2-5 minutes.
9.
On the Query
1-Minute Data tool push Get Data.
10.
Enter the Air
MFC, Gas MFC, CH1, CH2 and CH3 data in the appropriate blank for the NO3 NO GRC
Point 1 on the Gas Calibration Worksheet in the As Left section.
11.
The RF is now
displayed at the far right of the worksheet.
If the RF is between 0.98 and 1.02, the calibration adjustment is
complete. If the RF is not within spec,
repeat the adjustment part of the procedure again. (Note:
In some cases CH3 will be higher than 1.02. Make sure that CH1 and CH2 are in spec.)
12.
When the
instrument is finished being tested make sure to put it back into the run mode.
13.
Close the Trigger
Cals and Query Data windows.
14.
Save the Gas
Calibration worksheet, and then print the NO3/NH4 information and fax it to