Chapter 3 Detailed Operating Instructions
20
15. Press the ON/OFF button once to return to the present
readings screen. Turn off the valve on the regulator and
disconnect the CO2 source.
NOTE:
The regulators used for calibration must have a flow rate of
at least 1 liter per minute.
Toxic Gas Sensors
The gas channel will accept any of Metrosonics se-4000 series
toxic gas sensors. We currently offer sensors for ten different gas
types:
1. Carbon Monoxide (CO)
2. Hydrogen Sulfide (H
2
S)
3. Nitrogen Dioxide (NO
2
)
4. Nitric Oxide (NO)
5. Hydrogen Cyanide (HCN)
6.
Ammonia
(NH
3
)
7.
Oxygen
(O
2
)
8. Ethylene Oxide (ETO)
These sensors are based on well established electrochemical
sensor technology. They are designed to be maintenance free and
stable for long periods of use.
The following table illustrates the cross-sensitivity to a range of
commonly encountered gases, expressed as the reading of the
sensor when exposed to 100 ppm of the interfering gas at 20°C:
Gas Sensor
Interfering
Gas
CO
H
2
S SO
2
NO NO
2
H
2
Cl
2
HCN
C
2
H
4
HCl
CO
se-4010 100
≈
7
<10 <9
<20
<40 N/D
N/D
N/D
N/D
H
2
S
se-4020 <2 100
≈
10
≈
1
≈
-20
≈
1 N/D
N/D
N/D
N/D
NO
2
se-4050 -5 <5
<-0.5 0
100 N/D N/D N/D N/D N/D
NO se-4060
0 N/D
≈
5
100 <30
N/D N/D
N/D
N/D
N/D
HCN se-4070 N/D N/D N/D N/D N/D N/D N/D 100 N/D N/D
NH
3
se-4080 0
≈
100
≈
60
≈
20 <10
0
≈
-50
≈
5
N/D
<10
Power is automatically applied to toxic gas sensors when they are
connected to the IAQ Monitor and the IAQ Monitor is turned on.
After initial turn on, the IAQ Monitor will identify that a biased
sensor is connected. You can then turn off the IAQ Monitor and it
will continue to power the sensor to maintain the bias. When power
is first applied, the sensor will take a few minutes to stabilize.
Biased sensors should remain powered at all times.