Hi there. My wife and I have been having an ongoing issue with the wired smoke alarm system that is installed in the condo that we live in (the condo was built 3 years ago). Basically, no matter how often we've tried to replace the backup batteries with brand new ones (9V Energizer Alkalines) in all of our wired units, the one in our upstairs hallway still seems to go off with no provocation whatsoever at odd hours of the day (all of the other alarms are always silent). Why would a wired smoke alarm system continue to have a single chirping alarm even though all of the backup batteries have been replaced with brand new ones for all units in the house?

What's even more bizarre, this is now the third time we've had to use one of the original (old) batteries, a GP SuperCell 9V Alkaline, that was previously installed in a different unit in the house to silence the troublemaker one in the hallway. Why is it that placing one of the old batteries back into the chirping unit silences it when a fresh, brand new battery should have done that instead? The Property management company we rent this Condo from thinks we're simply either crazy for reporting this issue or to simple to replace the batteries that we clearly have. Any advice or suggestions would be greatly appreciated!:confused:

Clean the sensor in the detectors with a can of air.

Is there any possibility that the smoke alarm is near a humid place like the bathroom or any place where condensation can occur?

I installed 5 Interconnected AC w/battery backup smokes, that continuously false chirped. BRK was the manufacturer, They had a recall, but it was for earlier manufacturer date. They replaced 3 that would randomly chirp. Problem persisted, then they replaced all 5, works fine now. Ends up they felt the defective one was causing othes to chirp.
What a pain, They work fine now. They had always been wired correctly and with new batteries.