Teledyne API Model 200AH NOX Analyzer Instruction Manual, 06492, Rev. G2
9-24
9.2. Performance Problems
When the response from a span check is outside the control limits, the cause for the drift should
be determined, and corrective action should be taken. Some of the causes for drift are listed
below:
NOTE
It has been our experience that about 50% of all analyzer performance
problems are sooner or later traced to leaks in some part of the system.
1. Fluctuations in flow, caused by leaks or plugged orifices.
2. Lack of preventive maintenance.
3. Change in zero air source.
A. Air containing NO leaking into zero air line.
4. Change in span gas concentration.
A. Zero air or ambient air leaking into span gas line.
B. Calibration gas tank exhaustion.
5. Leak in the NO/NOx or AutoZero switching valves.

9.2.1. AC Power Check

1. Check that power is present at main line power input. Verify that correct voltage and
frequency is present. If unit is set for 240 VAC and is plugged into 115 VAC it will appear as
no power fault.
2. Unit is plugged into a good socket. Analyzer must have 3-wire safety power input.
3. Check circuit breaker. Circuit breaker is part of the front panel power switch. It is set each
time the instrument power is turned on. If there is an internal short causing a trip, the switch
will automatically return to the OFF position when an attempt is made to turn it on.