Whenever the alarm is operating, the green Power LED flashes every 30
seconds to indicate the unit is monitoring for CO. If the alarm senses
dangerous levels of CO, the red Alarm LED will flash and the alarm will
emit an audible alarm pattern.
5. Model 900-0233 Operating Characteristics
Operating and Alarm Characteristics
Function LED Display
Alarm Sound Unit Status
Recommendation
Normal
Operation
Green LED
flashes every 30
seconds
None
Normal DC
operation (sensing
no CO) and with
good batteries
None
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 30 seconds
One quick
beep every
30 seconds
Batteries need to be
replaced
Replace all three AA
batteries
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 condition continues,
unit has
malfunctioned.
Replace immediately.
Unit will not respond
to 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
End of
unit life
indicator
Red LED flashes
two times every
30 seconds
Two quick
beeps every
30 seconds
End of unit life
Replace unit
immediately. Unit will
not respond to to CO
6. Model 900-0230 (with digital display)
Operating Characteristics
When the unit is first powered up, the green Operate LED flashes once
every 30 seconds and the digital display will show three “eights” –
indicating the alarm is in the start-up mode. The three “eights” will
remain for approximately 30 seconds. Then, the alarm will display “0”
and begin monitoring the air for CO and will continue to do so as long
as it receives power.
This alarm will display a “0” if CO concentrations between 0 and 30
PPM have been detected within the last 15 seconds.
