AIR SYSTEMS INTERNATIONAL CO-91 Series User manual

Printed in U.S.A
©Copyright Air Systems International, Inc. 2003. All Rights Reserved.
AIRSYSTEMSINTERNATIONAL,INC.
829 Juniper Crescent, Chesapeake, Va. , 23320
Telephone [phone]
Toll Free 1-800-866-8100
Fax No. [phone]
http://www.airsystems.cc
e-mail: [email protected]
SENSOR REPLACEMENT AND CALIBRATION
PROCEDURE FOR CO-91 SERIES
CARBON MONOXIDE MONITORS
Manual No. MON045
(Rev 2 November 2003)
Air Systems International, Inc.
Registered to ISO 9001
Certificate No. A5033

-2-
SENSOR REPLACEMENT
STEP 4)
Remove sensor from sensor cup and remove leads . Take
the new sensor and remove the metal spring. Reattach
leads to the proper colored terminals on the new sensor.
Install new sensor into sensor cup.
STEP 5)
Reassemble monitor and install back into system.
Connect all external connections. Allow monitor
to stabilize 30 minutes to 1 hour and recalibrate.
STEP 3)
Remove end plate to gain access
to the sensor cup from outside the
housing.
STEP 1)
Disconnect all external connections.
Remove CO monitor from the unit.
STEP 2)
Remove the four screws from the monitor’s
left end plate.
Note: Alarm location may vary.
Replacement sensors are shipped with a metal spring installed between the electrodes. Do not remove the clip
until the sensor is to be installed into the monitor.
Note: Currently, there are two types of sensors being shipped. Please check your sensor
lead connections and follow sensor connection instructions below.

-3-
CALIBRATION PROCEDURE
Do not use inert gases to zero the monitor. This will cause premature failure of the sensor.
CO Zero Adjustment
To zero the instrument, follow the steps below. Zero calibration gas should be used to properly “zero” the
instrument and assure that a valid calibration is achieved. If zero adjustment cannot be made as indicated, sensor
replacement may be necessary. After each monitor adjustment outlined in the following steps, allow time for the
changes to stabilize.
Note: A controlled orifice in the
regulator will allow the gas to flow
at approximately 300 cc/min.
6. Attach the clear tubing with male plug to the monitor
air sample inlet.
7. Open gas regulator fully by turning the knob at least
two (2) turns counterclockwise.
8. Allow digital readout to stabilize approximately 15 -
30 seconds.
9. Adjust "zero" pot adjustment screw (clockwise to
increase, counterclockwise to
decrease) until a "00" reading
is obtained.
10. Turn off the regulator and disconnect the tubing from
the zero air regulator.
1. Place the “on/off/test” switch to the “on” position.
2. Allow 30 seconds for the readout to stabilize.
The green indicator light will illuminate.
3. Hold the “on/off/test” switch in the “test”
position. The following will occur:
• Audible alarm will sound
• Green indicator LED will flash
• Amber low battery indicator
LED will illuminate
• Red lamp on
This test ensures the circuitry is operable and the
continuity to the sensor is proper. Release the switch.
4. Remove air sample inlet tube.
5. Install regulator on the zero air cylinder reference gas.

-4-
CO SPAN ADJUSTMENT
Use only 10 - 20 ppm CO gas for calibration. Using a higher concentration may decrease accuracy at
lower scale readings. Note: 10ppm gas must be used to satisfy Canadian calibration requirements.
5. Adjust the "span" pot adjustment screw
(clockwise to increase, counterclockwise
to decrease) until the digital display reads
the same concentration (ppm) as printed
on the calibration gas cylinder.
6. Turn regulator off and repeat “zero”
adjustment procedure above. Display
should return to a "00" reading.
THE MONITOR IS NOW CALIBRATED AND
SHOULD BE RECALIBRATED MONTHLY OR IF
ACCURACY IS QUESTIONABLE. CHECK
LOCAL REQUIREMENTS AND RECALIBRATE
AS REQUIRED.
1. Install regulator to the CO calibration
gas cylinder.
2. Connect the plug to the monitor.
3. Open gas regulator fully by turning the knob at
least two (2) turns counterclockwise.
4. Allow digital display to stabilize
approximately 15 - 30 seconds.