PROGRAMMING
4 - 7
4.4.1 Fresh Air Calibration
This procedure determines the zero point of the sensor
calibration curve. To perform fresh air calibration, the
calibration adapter, a bottle of “fresh” air, and a Tedlar bag
(optional), or a charcoal filter are required. The “fresh” air is
clean dry air without any organic impurities. If such an air
bottle is not available, any clean ambient air without detectable
contaminant or a charcoal filter can be used.
The calibration adapter links the inlet port of the UltraRAE
monitor to the Tedlar bag or the charcoal filter. First fill the
Tedlar bag with “fresh” air from the bottle before starting.
1. The first sub-menu shows: “Fresh air calib?”
2. Insert a new, unused, RAE-SEP tube into the monitor and
secure the cap. If a “fresh” air bottle is available, fill the
Tedlar bag with the “fresh” air. Next, snap the calibration
adapter over the inlet port of the UltraRAE monitor and
connect the other end of the tube to the Tedlar bag. If a
charcoal filter is used, connect the filter to the inlet port of
the UltraRAE monitor. If the “fresh” air bottle or charcoal
filter is not available, make sure the monitor is in an area
free of any detectable vapor.
3. Press the
[Y/+]
key. The monitor will identify the inserted
tube and display the tube name. If the tube cannot be
identified, the tube can be manually selected by responding
with
[N/-]
until the correct tube name is displayed.
4. Press the
[Y/+]
key when the correct tube name is displayed
to start “fresh air calibration” of the monitor. The display
shows “zero in progress” followed by “wait..” and a
countdown timer.
5. When the sampling is complete, the display will show the
message “zeroed… reading = 0.0 … done!” The next sub-
menu will be displayed (“Span calib?”).
Note:
The charcoal filter has a check box so that user can mark
off a box each time the filter has been used. The charcoal filter
should be replaced after four calibrations.
