Originally posted by: Shooters
It keeps chirping because it's also wired in the back. Either put a new battery in it or detach it from the wall and pull out the plug in the back.
In my house, there are about 10+ smoke detectors and they are all wired together as well as to the power. I replaced the battery proactively, and it kept chirping for a while.
So, I was trying to figure it out, and held the test button in a little too long and EVERY ONE IN THE HOUSE went off, was insane... and you have to hold the button in again to make it stop going off, which is not intuitive or quick.
Anyway, eventually it stopped chirping after I replaced the battery again (took it out, put it back in, etc). I'm not sure if I unplugged it completely from the chain if the others would flip out or not... but... the easiest solution is to replace the batt and give it a few moments to reset I guess.