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1.
THE GAS-SENTRY CGA-411 AND CGA-412 DETECTORS
The CGA-411 and CGA-412 detectors monitor continuously natural gas (methane),
carbon monoxide and hydrogen sulfide, and oxygen, and display the concentration of a particular
gas selected by a front panel switch and alarm acoustically and visually if any of the monitored
gases exceed preset limits. These detectors may be used to:
* test the atmosphere of an enclosed space prior to entry and monitor it after entry
* test ambient air for natural gas
* bar hole
* locate and track gas leaks in pipes and other conduits
* test for carbon monoxide and hydrogen sulfide in ambient air
* test for carbon monoxide in flue gas and other gases given off by appliances
Displays for the CGA-411 and CGA-412 detectors are selected by a front panel switch.
They include:
% GAS
PPM CO
% OXYGEN - Displays the concentration of oxygen in volume percent
In addition, the TRACK GAS scale may be selected by the front panel switch. This scale
operates as follows:
TRACK GAS - Detects and displays the concentration of natural gas (methane) and
The gas concentration on the TRACK GAS scale is displayed as:
This is the only difference between Models CGA-411 and CGA-412.
Alarms
The CGA-411 and CGA-412 detectors alert the user acoustically (with a sound alarm or
beeper) and visually (by "flashing" on the display the appropriate symbol) whenever the
concentration of a detected gas rises above or falls below a preset limit. The alarm limits can be
set by the user as described later in this manual.
- Displays the concentration of methane in air in percent by volume
- Displays the concentration of carbon monoxide in parts per million
(ppm) by volume; this display also shows the detector response to
hydrogen sulfide
operates a beeper for locating a gas leak.
Model CGA-411
Model CGA-412
Display is % LEL
Display is % GAS
2
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