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6. The 900-0235 Operating Characteristics
Carbon
monoxide
alarm
Red LED flashes with
beeps.
4 quick beeps,
5 seconds silence,
repeating
Alarm condition.
Dangerous
concentrations of CO
detected
Refer to “What to do
When the Alarm Sounds”
(inside front cover)
Low
battery
Red LED flashes every
15 seconds
One quick beep
every 15 seconds
AC powered and low
or missing battery
Install or replace 9V
battery.
Error/
service
alarm
Red LED flashes every
30 seconds
One quick beep
every 30 seconds
Unit is in error condition
Error
Red LED
constantly on
Constant alarm
Very low battery or unit
malfunction
Replace battery.
If “Err” continues, unit
has malfunctioned.
Replace immediately. Unit
will not respond CO
Normal
Test/Reset
function
Red LED flashes with
beeps. Green and
amber LED’s on
4 quick beeps,
5 seconds silence,
repeated once
Normal operation when
Test/Reset button is
pressed
CO not detected. Alarm
for test purposes only
Operating and Alarm Characteristics
Function
LED Display
Alarm Sound
Unit Status
Recommendation
Normal
Operation
Green LED
constantly on
None
Normal AC
operation (sensing no
CO) and with a good
battery
None
Normal
Operation
Green LED flashes
every 7 seconds
None
Normal DC operation
on 9V battery backup
Verify AC power is
restored as soon as
possible to conserve
battery. Replace battery.
When the 900-0235 CO alarm loses power:
If you have a good 9V battery
installed, the alarm will automatically switch to the battery backup mode and
the green LED will flash approximately every 10 seconds. The unit will continue
to operate normally and detect CO for at least 20 hours.
If the battery is low or missing, or if the unit malfunctions, it will alarm
differently to alert you of specific conditions. Please familiarize yourself, and
other family members, of the difference between a CO alarm and an
indication signifying a problem with the unit.
When AC power is restored, the alarm will automatically switch back to
normal operating mode and the green LED will come on continuously.
Observe the CO alarm regularly to make sure the green Operate LED is on,
indicating normal operation. If the green Operate LED is not on, unplug the
CO alarm, then plug it in again. This will clear the alarm for restart. If the
green operate LED does not light, your CO alarm may be malfunctioning.
The following table describes the audible alarm patterns and the
recommended actions to take.