Peak Level Display (Cont.)
Concentrations of CO between 0 and 30 PPM can often occur in normal,
everyday conditions. Concentrations of CO below 30 PPM may be an
indication of a transient condition that may appear today and never
reappear. Just a few examples of conditions and/or sources that may
cause low level readings are heavy automobile traffic, a running vehicle
in an attached garage, an appliance that emits CO when starting up, a fire
in a fireplace or charcoal in a nearby barbecue. A temperature inversion
can trap CO generated by traffic and other fuel burning appliances causing
low level readings of CO.
Normally, the digital display will read “0” and under certain conditions you
may notice levels of 30 or more for short periods of time, by using the
Peak level memory feature on the Nighthawk CO alarm you can view the
highest concentrations of CO detected.
10
Features and Operation
(cont.)
Other Possible Displays and Their Meanings
The following symbols will appear on the display during normal
or error operations, and are explained below.
Normal Operation
Normal operation (see figure 6) with a full
battery. The dot in the lower right corner
cycles on and off every 5 seconds. If CO is
present the display will indicate the reading in
Parts Per Million (PPM).
Normal Operation following Power-up or Reset
Figure 7 shows the normal display immediately
after installing batteries or after the test/reset
button is pressed. The display should change to
the normal display (see figure 7) approximately
30 seconds after pressing the test/reset button.
(see Test/Reset Button page 13).
If the test/reset button is pressed, the alarm will sound. The
display will show a number during the time that the alarm is
sounding. This number is a normal part of the test function, and
does not indicate a CO reading.
Ignore the number during
the test/reset procedure.
Peak Level Display
When the peak level button is pressed and
held, the display shows the highest CO reading
taken by the CO alarm since its last peak level
reset or power-up. The battery fuel gauge
changes to show only the top segment of the battery to indicate
that peak level is being displayed (see figure 8). In this example
120 PPM was the maximum amount of CO recorded since the
unit was last reset (see Alarm/Danger Levels on pages 19-23).
Although the peak level feature will display levels below 30 PPM,
these levels will not result in an alarm no matter how long the
device is exposed to these levels.
9
Features and Operation
(cont.)
Figure 6
Figure 7
Figure 8
Benelux Guide 21/8/01 2:15 pm Page 9
