Use and Care Manual
6. Model C3010-D (with digital display) 
 Operating Characteristics
The following table illustrates the possible digital displays, describes the 
audible alarm patterns, and the recommended actions to take.
Operating and Alarm Characteristics
LCD Display Shows  Alarm Sound  Unit Status  Recommendation
A steady display of 
CO concentration 
from 30-999. Red 
LED flashes with beep
4 quick beeps,
5 secs. silence,
repeating 
Alarm condition. 
Dangerous 
concentrations of 
CO detected
Refer to “What to 
do When the Alarm 
Sounds” (inside front 
cover)
Brief “888” for 
approximately 30 
seconds
None
Self test when first 
powered up
None – CO has 
not been detected. 
Numbers shown for 
test purpose only
“- - -” 
followed
by 
“888” are 
shown to indicate 
test mode
4 quick beeps,
5 seconds 
silence,
repeated once 
Test/Reset button is 
pressed
None – CO has 
not been detected. 
Numbers shown for 
test purpose only
Steady “0” displayed, 
dot flashing every 5 
seconds, Green LED 
 flashes every 30 secs.
None Normal DC 
operation with 
good batteries 
(sensing no CO)
None
“
Lb” flashes 
alternately with 
any number, 
Amber LED flashes every 
second. 
One quick beep 
every 60 seconds
Unit batteries are not 
capable of powering the 
unit either because of age, 
storage or the voltage of 
the battery
If unit is cold, allow to warm 
up above 68°F. If the unit is 
at room temperature and is 
beeping /flashing every 60 
seconds the unit needs to be 
replaced.
“Err” displayed, 
Amber LED flashes 
every second and 
green LED flashes error code 
every other 30 second period.
One quick beep 
every 30 seconds
Unit is Error 
condition
Press and hold the test
button for 5 seconds to
perform a reset. If unit
continues to beep or
alarm, using a screwdriver
slide the switch on the
back of the unit up to the
shut down position. Unit
will not respond to CO.
Display is blank Constant alarm Unit malfunction
Number from 
11-999 displayed. 
None Peak Level Memory 
activated. Highest 
concentration of 
CO detected is 
displayed
Refer to following 
section for informa-
tion regarding Peak 
Level Memory
“End” displayed.Green 
LED flashes error code 
every other 30 second 
period and amber LED 
flashes every second.
Two quick 
beeps every 
30 seconds
End of unit life Replace unit imme-
diately. Unit will not 
respond to CO.
The problems listed above are under normal operating conditions. Other 
“Err” conditions could exist. If you should have any questions regarding 
display conditions, call our Consumer Hotline.
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