8
To Detect Carbon Monoxide
Carbon Monoxide in Ambient Air
Connect an appropriate probe with a water-block filter and select the Monitor mode. After
warm-up, the display shows the concentration of CO in parts per million (ppm). If the air is clean
(contains no carbon monoxide), the display should read zero. If it does not, use the right “Zero/Off”
button to obtain a new zero in clean air.
Carbon Monoxide in Flue Gas
Connect the flue gas probe, with an attached flue gas filter, to the water-block filter on the
hose and select the Monitor mode. After warm-up, insert the probe into the flue and read the
concentration of CO in parts per million. A flue gas check of CO should take one minute or less.
For every minute of flue gas sampling allow the detector a minute of room air sampling to dry the
filters.
Note:
The standard flue gas probe and filter are suitable for spot checks lasting a
minute or two. For measurements of CO in flue gas over longer periods use an
Extended Duty Flue Gas Probe and Filter (Part No. FP-012).
“Air-Free” CO Flue Measurements.
The EGA-411/412 and 611/612 detectors can display measurements of CO on an “air-free”
basis if this feature is selected (see Part 2). When this selection is made, the measured CO
concentration is referred to air-free flue gas according to:
"Air
−
Free"PPM CO
=
20.9
(20.9
−
measured
% 0
2
)
(
measured ppmCO
)
The instrument displays CO concentrations on an air free basis using the above relation.
The CO reading on the display is label by ppm AFCO, i.e. air-free CO. This calculation is used
up to 16% Oxygen. Beyond this, CO concentrations are displayed without conversion, i.e. the
“air-free” formula is
not
used.
WARNING: Do not touch the flue probe immediately after a measurement. Wait until
it cools. Running the instrument in air helps cool the probe.
The filter provided with the flue probe
must
be used to avoid interference by
nitrogen oxides in combusted gas. A filter is good for about three months of
ordinary use. It should be replaced or refilled when about 90% of its purple
material has changed color to brown, or when it gets clogged or flooded (see
"Accessories and Spare Parts", Flue Gas Filter, Part No. FF-005 and Purple
Beads and Spare Retaining Disks, Part No. PR-050).
CAUTION:
Summary of Contents for GAS-EXPLORER II EGI-201
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