Smoke Detectors Going off for no reason

topic posted Sat, February 17, 2007 - 6:26 AM by  Bryan
My house has soke detectors that are wired into the electrical system and also have a battery backup. About a month ago I was cooking and the oven got a little smoky and the smoke detectors went off. Ever since then they will go off at random times for twenty seconds or so. It happens about once a week. This morning they all went off. There was no fire, no smoke, nothing. I had to unhook them all from the wiring to get them to stop. Any ideas why they are going off like this, or how to fix them?
posted by:
  • Unsu...
    Sometimes they go off like that to let you know the batteries need replacing (the batteries are a backup incase of a power loss) and other times (depending on the brand) they need to be cleaned.

    If you don't have the manual for them, google up the manufacturer and then look for the model number (you might have to take one apart to get all of the pertinent info) - the manual will tell all.

  • You probably have the first generation of hard wired smoke detectors. The first generation smoke detectors had batteries that where builtin and cannot be replaced. The batteries assured that the detectors would work when the power was off. However after a number of years the batteries wore out and when they did the alarm went off to signal that the detector no longer had backup power.

    The only thing that can be done now is to replace them. The new er hard wired detectors have replaceable batteries so this is no longer a problem.

    One funny thing though rather annoying is that if several detectors werer installed in a house at the same time they will often burnout at the same time and all go off at once - once had a client where this happened - all five at the same time.

    Good luck.

    • When I worked for a state college in the summer we would go around with compressed air tank (not a can) and blow all the shmootz and dust out of it. This was to keep them from going off regularly. It may be they are first gen, it may be there some stuff in there, or they may be possessed.
      • low batteries can be a cause

        poor air circulation can be a cause

        exposure to soot or grease or smoke (even candles or oil lamps or ear candles....)

        placement too close to cooking stoves/ovens, fireplaces, wood stoves--in rare cases strong drafts with dramatic change in temperature
        • wow looks like NO one can really read here

          this is some kind of hard wired system with a backup battery

          odds of a rechargable backup battery being worn- low but a possible cause.

          more likely the whole system needs to be reset somehow, once you triggered it, it's electronics got weird for lack of an intelligent sounding answer

          it mgiht get worse- a friend recently moved from a place with a hard wired system that basically went off for a few seconds every 15 minutes or so - for months, and these idiots basically put up with it
  • Bryan- I've had a lot of experience with this type of smoke detector in some of my units. Here's what I've learned about them:

    1: They need to be cleaned and RESET a few times a year. Resetting a smoke detector can be achieved by holding the test button down for as long as 20 seconds. Clean with canned air.

    2: They shouldn't be installed within 10 feet of a kitchen. Even right outside the kitchen doorway is too close.

    3: Hardwired smoke detectors tell you when they need batteries, which, if you use good ones, isn't very often. Don't forget to reset when you do this.

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