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Part Five – Technical Information
How the Unit Determines When to Alarm
Your Nighthawk alarm uses advanced technology to monitor the
environment in your home and warn you of unacceptable levels of
carbon monoxide or Gas. An internal microcomputer works togeth-
er with the sensors inside the alarm to determine the levels of carbon
monoxide or Gas in the air. The microcomputer is calibrated to trig-
ger the unit’s alarm before most people would experience any symp-
toms of carbon monoxide poisoning or in the case of natural Gas or
propane, the alarm will trigger before 25% of the lower explosion
limit (LEL). Because carbon monoxide is a cumulative poison, long-
term exposures to low levels can cause symptoms, as well as short-
term exposures to high levels. Your Nighthawk unit has a time
weighted alarm, so the higher the level of carbon monoxide pre-
sent, the sooner the alarm will be triggered.
This Nighthawk alarm meets the alarm response time
requirements of UL Standard 2034 which are as follows for CO:
At 70 ppm, the unit must alarm within 60-240 minutes.
At 150 ppm, the unit must alarm within 10-50 minutes.
At 400 ppm, the unit must alarm within 4-15 minutes.
This Nighthawk alarm meets the alarm response time
requirements of UL Standard 1484 which are as follows for Gas:
This unit shall alarm before 25% of the LEL of either natural Gas or
propane is detected. In all cases, the unit will detect carbon monoxide
as a priority over Gas. If the device is detecting Gas, then detects an
amount of CO to cause an alarm, the device will stop alarming for
Gas and alarm for CO.
WARNING: This product is intended for use in ordinary indoor loca-
tions of family living units. It is not designed to measure compliance
with Occupational Safety and Health Administration (OSHA) commer-
cial or industrial standards. Individuals with medical problems may
consider using warning devices which provide audible and visual sig-
nals for carbon monoxide concentrations under 30 ppm.
Accuracy of the Digital Display
Each Nighthawk CO and Gas alarm is calibrated at a CO concentration
of 150 ppm in air, at 80˚ F (+/- 10˚ F) and 40% (+/- 3%) relative humid-
ity. Depending on the ambient condition (temperature, humidity) and
the condition of the sensor, the
alarm
readings may vary. Under the
same ambient conditions the device will alarm for Gas before 25% of
the LEL is reached.
The digital reading tolerances are:
Ambient: 80˚ F (+/- 10˚ F), atmospheric pressure +/- 10%, 40% +/- 3%
relative humidity.
Tolerance
Reading (of displayed reading)
0-999 ppm +/-20% +15 ppm
Product Specifications
Power:
120V AC units: 60 Hz, Current 120 mA max.
Sensor:
CO sensor calibrated at 150 ppm (±25 ppm).
Gas sensor calibrated to alarm before 25% of the LEL.
Temperature:
Operating range: 40˚F (4.4˚C) to 100˚F (37.8˚C).
Mounting:
Accessories supplied for wall mount or direct plug
applications.
Alarm:
85+ dB at 10’ @ 3.4 ± 0.5 KHz pulsing alarm.
LED Operation:
Blinking dot on display denotes normal operation.
Digital readout 30-999.
In alarm condition for CO you will hear 4 quick
beeps, 5 seconds off, repeating for CO.
In alarm condition for GAS you will hear a 1/2 second
beep, 1/2 second silence, repeating for GAS.
Battery Backup:
A 9V battery is needed. If battery is low or
missing while the unit is plugged into a 120V outlet,
an “Lb” message will display which will blink
alternately with a the CO reading every second and
the sounder will chirp every 15 seconds.
Unit Malfunction:
“Err” error message will display. Intermittent
alarm will sound every 30 seconds.
Refer to pages 1-6, 6-3 and 6-4 for other error
conditions.
Test/Reset Button:
Test button verifies proper unit operation and resets
the unit in the event of a CO and Gas alarm.
Peak Level Memory Button:
When pressed, LED will display the highest CO
ppm level detected since unit was powered up or
since unit was reset with test button. Reading will
be stored in memory as long as unit is not reset
or unplugged. Any CO concentration detected from
11-999 will be displayed
Size:
6”L x 3.75”W x 1.8”H. Wt. 1 lb.
Warranty:
Five-year warranty from date of purchase against
defects in material and workmanship.
5-1
CO/Gas Alarm Manual Rev. C 3/21/01 11:37 AM Page 19