Teledyne 2240 - Portable Handheld Hydrogen Leak Detector, 3rd generation (revision 2/29/08) - Manual (Page 18)

Startup and Operation Model 2240
Teledyne Analytical Instruments 8
0.001%) reading after exposure to hydrogen. If the instrument doesn’t
return to an indication of less than 0.001% after 5 minutes in a
hydrogen-free environment then invoke the Reset operation (See Section
2.9).
2.6.1 Hydrogen Concentration—LCD Display
The upper line of the Controller LCD indicates a numerical value
or range for the percent hydrogen concentration or peak hydrogen value.
The lower line is used to display the hydrogen meter, a logarithmic bar
graph ranging from 0.001% (10 ppm) to 100% hydrogen by volume. An
open box on the bar indicates the last peak value obtained and filled
boxes indicate current value. Figure 2-4 shows how to interpret the
hydrogen meter:
Figure 2-4: Lower Line LED Bar Graph
2.6.2 Hydrogen Concentration—Probe Tip
The Probe Tip LED Indicator can be used to show an increase or
decrease in hydrogen concentration.
Leak detection is accomplished by watching the Probe Tip LED
and moving the sensor around a potential hydrogen leak. During the leak
check:
1. The Probe Tip LED turns red and remains red when the most
recent peak hydrogen concentration is being detected.
2. The increase in hydrogen concentration will also be indicated
by the increasing number of yellow LEDs powering on in the
LED bar graph array.
3. When the Probe Tip LED turns orange, this indicates that there
is still hydrogen present, but the hydrogen concentration is