Hard wired smoke detector attachment point beeps after detector is removed

[Chuckanut]

I helped a friend try and figure out what is going on with her smoke detector that is hard wired into her home. We removed the detector and the battery in it . Yet we keep hearing the occasional beep every 45 seconds. It seems to be coming from the mounting hole in the ceiling, where the three electrical wires are. Is there a speaker in that area? I thought the speaker is only in the the detector itself.

 

[braumeister]

Smoke detectors are frequently wired together, so you may be hearing a different one.

 

[JoeWras]

Smoke detectors are frequently wired together, so you may be hearing a different one.

Agree. There should be no hidden speaker or anything like that.

The beeps are notorious for being non-directional. We have 8 detectors and every time one goes, it is a chore to figure out which of about 3 it could be.

BTW, sometimes there are smoke detectors in attics. Is there an attic, and did you peek up there? That would sound like it is coming from the box.

 

[SecondCor521]

Yup, it's code in my state that all the smoke detectors are wired together. If one goes off, they'll all go off (in a real fire, not the test button). Maybe this is even in the national code, I dunno.

One way I've discovered to determine directionality is to start in the center of my house and pick a direction to point my body, close my eyes, wait for the sound, and then see if I think the sound is from my left or my right. I can then either turn 90 degrees and repeat the process, or move in the direction of the sound if it's obviously louder on one side. If you always move between detectors (rather than under detectors), you'll have an easier time of it.

 

[GalaxyBoy]

OP mentioned "three wires." Two are power; the third is what ties multiple smoke alarms together so that's a clue there may well be additional smoke alarms in the house. Look for at least one on each level of the house, one outside each group of bedrooms (often that's just one), and if the house is relatively new, one inside each bedroom.

But who knows? I saw some crazy stuff over the years designing fire alarm, like a new ceiling being added and devices left on the old, upper ceiling. Let your imagination run wild, and someone has likely done it at some point.

One caveat: I'm going by memory from my old w*rk days here, so don't use this guidance if you're installing or changing anything; I'm just trying to help you track down the "hidden" smoke alarm. Good luck!

 

[427Vette]

I have had service calls like this many times. The homeowner swears that one of the smoke detectors is beeping. They will go as far as removing all of them and put them in the garage or outside. When they finally call I will troubleshoot it and find a plug in style carbon monoxide detector behind a dresser that has failed, a faulty septic alarm or a sump pump with battery back up beeping. It could be lots of other things, keep looking you just haven't found it yet.