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9
9. Calibration Mode
This section describes how to perform a fresh air adjustment, an automatic span adjustment, and a manual
span adjustment on the SP-220. It also describes how to turn on the Calibration Mode password function.
9-1. Fresh Air Adjustment
RKI Instruments, Inc. recommends that the fresh air adjustment be performed in a fresh air area (area
known to be free of toxic and combustible gases and of normal oxygen content, 20.9%). If a fresh air
environment is not available, a cylinder of zero air can be used as long as the gas is applied through a
humidifier tube. Calibration kits for the SP-220 do not normally include zero air or a humidifier tube.