Teledyne API Model 200AU NOX Analyzer Instruction Manual, 02293, Rev. F
9-27
9.2.2 Flow Check
1. Check TEST function RCEL - this is the absolute pressure in the reaction cell. It should
be
1-4 in-Hg-A.
2. Check that pump is running. Check RCEL - TEST function for proper pressure.
3. Check that pump tubing is connected to rear of analyzer.
4. Test that the pump is producing vacuum by removing fitting at rear of analyzer and
checking for suction at fitting.
5. Check for flow upstream of the sample flow orifice and ozone orifice on the valve
assembly.
A. Remove the 1/8" fitting that carries sample. Plug the fitting on the sample flow block
with your finger and note the vacuum produced.
B. Remove the ozone fitting also and compare relative flow rates. Sample should be much
higher (1000 cc/min) than ozone (80 cc/min).
6. Check for broken flow or pressure sensor.
7. Leak check the analyzer. See Section 8.7 for leak check procedure.
9.2.3 No Response to Sample Gas
1. Confirm correct operation of analog output by performing Analog Output Step Test in
Section 9.1.3.5.
2. Confirm general operation of analyzer.
A. Check for AC Power, Section 9.2.1.
B. Do flow checks, Section 9.2.2.
C. Confirm that sample gas contains NO or NO2.
3. Check instrument electronics.
A. Do ELEC TEST procedure in DIAGNOSTIC menu Section 9.1.3.2.
B. Do OPTIC TEST procedure in the DIAGNOSTIC menu Section 9.1.3.3.
C. If the M200AU passes ET and OT, that means the instrument is capable of detecting light
and processing the signal to produce a reading. Therefore, the problem is in the
pneumatics or ozone generator.
4. Check ozone generator subsystem. Do the diagnostic test of the ozone generator
subsystem in Section 9.3.6.
5. Check for disconnected electrical cables to sensor module.