Teledyne 9110T instruction manual Calculating / Checking Converter Efficiency, Step

Model 9110T NOx Analyzer Troubleshooting & Service

12.7.10.2. NO2 Conversion Efficiency

The efficiency at which the NO2  NO converter changes NO2 into NO directly effects the accuracy of the 9110T’s NOx, NO and NO2 measurements. The 9110T firmware includes a Converter Efficiency (CE) gain factor that is multiplied by the NO2 and NOX measurements to calculate the final concentrations for each. This gain factor is stored in the analyzer’s memory.

The default setting for the NO2 converter efficiency is 1.0000. Over time, the molybdenum in the NO2

NO converter oxidizes and it becomes less efficient at converting NO2 into NO.

To ensure accurate operation of the 9110T, it is important to check the NO2 conversion efficiency periodically and to update this value as necessary.

∙For the analyzer to function correctly, the converter efficiency must be between 0.9600 and 1.0200 (96-102% conversion efficiency) as per US-EPA requirements.

∙If the converter’s efficiency is outside these limits, the NO2 converter should be replaced.

∙The current converter efficiency level is also recorded along with the calibration data in the DAS for documentation and performance analysis (Section 7).

12.7.10.3. Calculating / Checking Converter Efficiency

The 9110T to automatically calculate the current NO2 conversion efficiency by comparing a known starting concentration of NO2 gas to the measured NO output of the converter. There are three steps to performing this operation.

Step 1:

Supply the analyzer with a known concentration of NO2 gas, to the analyzer.

Figure 12-7: Setup for determining NO2  NO Efficiency – 9110T Base Configuration

Step 2:

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