Operating Instructions - Snap-on Equipment

Pocket PC Maintenance3. Remove the hose from the top fitting on the right of the sample filter bowland seal it. Repeat the leak check. If it now passes, the filter bowl isleaking and needs repair. The most likely problem is the O-ring seal.✓ After a successful leak check, it may be necessary to remove thehose discussed in Step 3 to relieve the system vacuum and allow thepump to run.Zero CalibrationIn normal operation the gas analyzer frequently performs a zero calibration. Duringthis check, the gas analyzer submits clean air, room air, into the sample system toverify that the analyzer reads properly when there is no gas present in the samplecell. FGA periodically performs zero calibrations as requested by the gas analyzer.In addition, you may perform a zero calibration at any time.To begin Zero Calibration,1. Press the Maintenance button on the main menu.— The Maintenance menu displays.2. Choose Zero Calibration.✓ To perform an auto zero, the probe must be sampling fresh room air, NOTvehicle exhaust.✓ You can set FGA whether to perform auto zero calibrations automaticallywhile in meters, strip chart or bar chart, or to notify you when an auto zerois recommended. Use Maintenance > Setup > General Setup > Misc toset this option. See Misc, page 2G-16.Figure 2G-14: Zero Calibration ScreenThe zero calibration runs.✓ Make sure the vehicle exhaust sample probe is in fresh air, NOT samplingany exhausts gases.2G-9