Zero Calibration (Oxygen Span) - Honeywell XT Series Operating Instructions Manual

11. Zero Calibration (Oxygen Span)

This must be performed in a clean atmosphere, and it is recommended that it be performed daily
or after any gas alarm. Depress the Test button for 5 seconds. The instrument will initiate a zero
by showing a countdown with a '0' for zero calibration, followed by a countdown from '20' to '0'.
When the zero calibration has been completed the XT will indicate a pass by beeping twice,
flashing twice, and the ( ) symbol will flash for 5 seconds.
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If the zero calibration is not OK then the XT will give a single beep and a single flash, the Test
Fail icon ( ) will be displayed, and the zero calibration should be repeated.
14 XT Series Personal Gas Detector