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Troubleshooting false smoke detector alarms?

Discussion in 'Security Alarms' started by blueman, Sep 3, 2008.

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  1. blueman

    blueman Guest

    Last night we had two false smoke alarms signaled from the same 3rd
    floor stairwell sensor. There was definitively no smoke, heat, or
    other environmental changes in the area.

    The sensor is an ESL 12-24V 4W Smoke Detector w/ Heat. It is wired
    together with a relay (The panel is a DMP XR200L 10-242).

    The alarm was professionally installed about 4.5 years ago.

    What are the likely causes of such repeat false alarms and how would
    one go about troubleshooting and verifying them?

    What is most likely - faulty sensor? dirty sensor? faulty relay? loose
    wiring? other?

  2. JoeRaisin

    JoeRaisin Guest

    First thing I would suspect is a dirty detector.

    Take apart the smoke chamber and clean it. They should be cleaned
    regularly anyway.

    You say it was professionally installed but when was the last time you
    had the system PM'd by a professional? Fire systems, especially in
    places where people sleep, need to have preventive maintenance performed
    on a regular basis.

    It is a pretty simple procedure and you can often get a reasonable rate
    if you sign a contract for annual tests. The technician will test the
    back-up battery, ensure wire integrity, check the sensitivity of the
    detectors, test and clean them and verify proper operation of all system
    components to include to notification appliances.

    This will help avoid false alarms, but more importantly the system is
    more likely to work when it is needed and get the people out.

    The only thing worse than no protection at all, is protection that
    doesn't work. Remember, it only takes one night without working
  3. blueman

    blueman Guest

    Just did it -- took apart and cleaned out the optical chamber with
    compressed air and gently swabbed the LED with a clean fine brush -- I
    will see what happens.
    They come by for a "wellness" visit every year. I also am pretty
    intimately familiar with most of my system but I have been lax in
    getting around to taking apart and cleaning our 14 smoke detectors
    (code required that number!)
    You are absolutely right.
  4. Matt Ion

    Matt Ion Guest

    I'll second that - I had one site where the drywall dust stirred up from
    construction was causing a detector to go off constantly... the
    construction crew just ripped the thing down... *sigh*

  5. - A few possibilities:
    Dust buildup
    Drywall dust
    installed too close to a bathroom door (shower steam)
    cleaning products or insecticide sprayed close to the detector
    loose wiring
    insect(s) in the detector or on the connectors
    rodents chewing on wiring
    flaky EOL relay
    voltage fluctuation
    faulty detector
  6. blueman

    blueman Guest

    Thanks to everybody for the input.
    I cleaned out the optical chamber (per the manual) and so far no alarm
    signal after 36 hours.

    Everything else looks good on physical inspection but if the cleaning
    doesn't hold then I will suspect either the device or the EOL relay
    since I think I can rule out the other potential causes.
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