PureAire Monitoring Systems, Inc.
10/25/07
17
5.1.4 Span Calibration from span gas cylinders
CAUTION: Be sure to observe all safety guidelines when generating and using
calibration gases.
Connect p/n 690100 calibration cap to the LEL sensor cell.
IMPORTANT: Be sure to perform the calibration with certified span gas
and within the recommended use date. PureAire recommends that you verify
that the concentration of the calibration gas is the same after calibration as
it was before.
1.
Connect the calibration cap to the LEL sensor.
2.
Open the regulator valve on the span gas cylinder and expose the sensor cell
to the span gas for 1 to 2 minutes until the gas reading stabilizes.
3.
If the correct gas concentration is not displayed; With the left indicator arrow
still lit, Hold the magnet over the UP SPAN or DOWN SPAN key and adjust
the display reading for the correct value.
NOTE:
For calibrating Gasoline using Hexane, hexane has a low vapor
pressure and the sensor cell will continuously rise, therefore only expose the cell
to a flow rate of 200cc/min for 1-2 minutes and then adjust the span to the
calibration standard. If the cell is exposed to higher flow rates the system will
rise too quickly and make it difficult to adjust the span.
4.
Close the regulator valve on the span gas cylinder and remove from the inlet
of the calibration cap. Remove calibration cap from the sensor cell by gently
rocking the cap as you pull downward. Permit the instrument to return to a
zero reading.
5.
Allow the instrument to return to a zero reading If the instrument has not
returned to zero after 3 minutes readjust the zero as required by repeating the
procedure outlined in section 5.3.4.
6.
Exit the Calibration mode by touching the magnet to the CAL key. The
instrument will return to normal operation after a one-minute delay.
NOTE: If the CAL mode is not exited manually, it will exit automatically after
five minutes of inactivity.
Calibration Cap
PureAire p/n 83505
Regulator, Model 715
500 cc per minute flow
p/n CZF7R000255
Order from Calgas/
Air Liquide
Calibration gas
Methane 50% LEL
p/n 6D360248
Order from Calgas/
Air Liquide
