Heath Consultants Gasurveyor 500 Series - Manual (Page 13)

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GENERAL INFORMATION
Ranges of Operation
LEL, 0 to 100%
The LEL range indicates the explosibility of the flammable
gas in the sample. This is displayed as a percentage of the
lower explosive limit (LEL) of the gas. For methane 100%
LEL corresponds to 5% Volume methane in Air.
The instrument range is displayed in the top right corner
of the display as % LEL. From 0 to 10% LEL the digital
display resolves to 0.1% LEL. From 10 to 100% LEL the
digital display resolves to 1% LEL. The analogue bar
graph follows in 4% steps. An example of the LEL display
is shown in Figure 2.1. Autoranging will automatically
switch the range to Volume Gas when 100% LEL is
reached.
The detection principle for this range is a catalytic reaction.
Figure 2.1 LEL Range
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