Kidde i12020ACA Manual page 15

Operation
LED Indicators
This alarm is equipped with red and green LED indicators:
The green LED (when illuminated) indicates the presence of
AC power.
The red LED (located under the test / hush button) has four
modes of operation:
Standby Condition: The red LED will flash every 40 seconds to
indicate that the smoke alarm is operating properly.
Alarm Condition: When the alarm senses products of
combustion and goes into alarm, the red LED will flash one
flash per second. The flashing LED and pulsating alarm will
continue until the air is cleared.
WHEN UNITS ARE INTERCONNECTED, only the red LED of
the alarm which senses the smoke or is being tested (the
originating unit) will flash. All other units in the interconnect
system will sound an alarm but their red LED's will NOT
flash.
Alarm Memory (Models i12020ACA and i12040ACA only):
This smoke alarm is equipped with an alarm memory, which
provides a visual indication when an alarm has been
activated. The red LED will illuminate for about 1.5 seconds
every 20 seconds to indicate the memory condition. The
memory will remain activated until pushing the test button
resets it or will time-out between 11 to 13 hours. The
memory will also reset if the battery voltage drops to 8 Volts
DC and when no AC power is present. In an interconnected
installation only the memory of the originating alarm will be
activated.
mode (Models i12020ACA and i12040ACA only):
Hush ®
The red LED will illuminate for 1.5 seconds every 10 seconds,
indicating the smoke alarm is in the Hush mode.
®
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