Operating Instructions - Snap-on Equipment

Pocket PC Maintenance✓ Always make sure the gas bottle values match the screen.✓ If the message does not clear after every calibration, replace the NO x cell.Other possible conditions that cause the NO x warning include,1. Calibration was run without gas in the cell.2. NO x cell has degraded by more than 20%.3. Bad NO x cell.Possible solutions include,1. Confirm that you are using a BAR97 calibration gas with NO x present.Confirm that you are using only an FGA calibration kit.2. The low NO x sensor voltage flag or bad NO x sensor flag is an indicator thatthe NO x cell has degraded by at least 20% from its original calibration. TheNO x cell is not necessarily bad and will still likely have a long life.3. If this message appears, run New NO x sensor from the menu (see NewNOx Sensor, page 2G-18). Next, rerun gas calibration (see GasCalibration, page 2G-1). This chould clear the NO x cell flag.4. After running, flow calibration gas and read the NO x cell.5. If it appears to read NO x properly, the NO x cell is fine.Leak CheckPerforming a leak check on the sample system helps to ensure that no vacuumleaks or hardware leaks exist to cause inaccurate readings. Leak check intervalsmay vary depending on the application and use, but once per week as part ofroutine maintenance is recommended, more frequently with heavy use.To perform a Leak Check,1. Press the Maintenance button on the main menu.The Maintenance menu displays.2. Choose Leak Check.— The Leak Check window opens.Figure 2G-11: Leak Check Start Screen2G-7