Security & Fire Protection Systems/FireX Smoke Alarm Chirping


Model 120-538C

Was changing batteries in smoke alarms on recently purchased home. Noticed the interconnect harness was not attached to the unit.

After installing a new battery I connected the interconnect 120V harness, now I know why it was not connected. It started chirping like crazy. Removed unit checked wiring for harness connected properly. I swapped the previously chirping unit to another harness elsewhere in home. Connected swapped unit( from other room) to harness and it started going off.

Any ideas?

I am guessing wiring harness isn't connected right some where but how to find. Home built 15 years ago, licensed electrician did all wiring as far as I know.


If you've changed out all of the batteries, then yes, most likely there is something not wired correctly. Have a licensed electrician experienced with home smoke detector systems check it for you. This is an old discontinued detector, probably near the end of it's service life anyway. You should consider replacing them all with newer units.

Take care,

Steve Burman

Security & Fire Protection Systems

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Steven Burman


Any question related to Closed Circuit Television (CCTV), Intelligent Video Analytics (IVA), Access Control Systems (ACS), Intrusion Detection Systems (IDS), Perimeter Intrusion Detection Systems (PIDS), and "Single Platform" Systems Integration Technical Writing and Documentation


25 years in the design and installation of security systems. 9 years experience in port and maritime security systems.

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