Sierra Monitor Corporation T10008 - Manual (Page 9)

OXYGEN DEFICIENCY MONITOR PAGE 7
6. Calibration
NOTE: This instruction assumes that only the internal sensor is in use
(external probe disconnected). See option instructions for calibration of
external probe.
6.1 Turn the monitor “ON” and place it in an environment containing
20.9% oxygen and 79.1% nitrogen. This can be supplied from a
calibration cylinder or can be open air if it is known to be clean.
6.2 Adjust the monitor to read 20.9% by turning the set screw which
is located on the right side of the monitor behind a black
grommet. Use a small jewels screwdriver to make the
adjustment.