Security & Fire Protection Systems/Firex model 120-1182


After stopping the chirping- the red led light is still flashing, in addition to the steady green led. What is the unit "telling me".
Thanks for the help.

Hello Don, and thanks for your question.

The key is how often the red LED is flashing.

Here's the deal on the LEDs from the manual:

LED INDICATORS: This smoke alarm is equipped with red and green LED indicators. The green LED (when illuminated) indicates the presence of AC power.

The red LED has four modes of operation:

1. Standby Condition: The red LED will flash every 30-40 seconds to indicate that the smoke alarm is operating properly.

2. 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 be flashing.

3. Alarm Memory: 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 16 seconds to indicate the memory condition. The memory will remain activated until pushing the Test/Hush Button resets it. The memory will also reset if the battery voltage drops to 8 volts. In an inteconnected installation only the memory of the
originating alarm will be activated.

4. Hush® mode: The red LED will illuminate for 1.5 seconds every 8 seconds, indicating the smoke alarm is in the Hush® mode.

Since you were dealing with a chirping issue, I'm guessing that the red LED is flashing once every 30-40 seconds, indicating normal operation.

Please let me know if this is not correct, and we'll go from there.

Best Regards,


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Dave Neuweiler


The design and application of burglary and fire systems for homes and businesses. Helping alarm owners understand how their system works. Helping to troubleshoot false alarm problems. Questions about monitoring issues.


Over a quarter century in the industry. Experience in installation, service, and monitoring centers. Training manager for a national protective services company; director of education and training for a national trade organization for for alarm dealers.


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