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  1. #1
    Join Date
    Mar 2006
    Location
    DFW
    Posts
    3,967

    Smoke detectors going off

    What would cause smoke detectors to go off when you open up a window? My mothers house has 4 smoke detectors wired together and when she opens a window they start going of after several minutes. I have installed some before and have never had this problem. Im wondering if Im going to have to change them all out. Anyone have any useful ideas?
    Eat a slice of Humble Pie.

  2. #2
    Join Date
    Feb 2003
    Location
    Huntsville,AL
    Posts
    4,125
    changing air flow path may be causing air to pick up solvents, etc --
    some sensors may be sensitive to rapid temperature change.

    what type of sensing do these have?
    ionization?
    photoeye?

    read the owner's manual--
    search mfgr web site
    harvest rainwater,make SHADE,R75/50/30= roof/wall/floor, use HVAC mastic,caulk all wall seams!

  3. #3
    Join Date
    Aug 2007
    Location
    MN
    Posts
    2,677
    neighbor burning wood?
    You can't fix stupid

  4. #4
    Join Date
    Jan 2008
    Location
    Lehighton, Pa.
    Posts
    178
    I used to have a detector in my home in the garage. During the summer months when it was really hot and humid the detector would go off for no reason. Could it be that the dense air can contribute to it going off?

  5. #5
    Join Date
    Apr 2002
    Posts
    11,808
    dust

  6. #6
    Join Date
    Feb 2006
    Location
    Tn.
    Posts
    1,344
    Strange RogerK...Grab the kneepads and start tracking low voltage for shorts or confused telephone installers.I saw an alarm wire the other day and almost used IT for my t-stat wire

  7. #7
    Join Date
    Oct 2003
    Location
    Valdosta Ga
    Posts
    847
    Try having someone turn off the power to them for about 15 seconds then reapply power listen for the first detector to go off. You will only have a few seconds befor theyall will go. but the first one shoud be the aera of the problem. (may be a bug in the sensor)

  8. #8
    Join Date
    Apr 2002
    Posts
    11,808
    the change in temperature problem explains why they want them 3 foot clear from a supply diffuser.

    supply diffuser can make the detector cool, compressor cycles off, and the detector is cold enough to make room air sweat.

    The photo-electric type have a little mirror in them that they bounce light off of. Smoke and ash scatter the light pattern and the alarm goes off.

    Condensation on the mirror will scatter the light, so will dust in outside air.

    The hard wired ones are interconnected so if one goes off, they all go off.

    So some detectors are installed on ceilings below attics. Opening a window changes how outside air flows through a home. When you run cooling cold air wants to fall.

    So if it is a two story place, opening a lower level window makes it easy for room air to leave the the house. This causes it to suck in attic air, many times through the junction boxes in celings and say out through a smoke detector.

    Other instance, wind pressurizes attic through vents in soffits or gables. Open a window on the leeward side of house and attic air pressure pushes through home and out window,

    Ride out a hurricane sometimes, you will be amazed at how air pressure moves through houses.
    Last edited by Carnak; 04-06-2008 at 11:07 AM.

  9. #9
    Join Date
    Jun 2003
    Location
    Florida
    Posts
    9,548
    Drywall dust will set them off along with other dusts I'm sure. Are they 120v wired together? I'd swap out the one by the window with another one and see if it still does it. They're not all faulty regardless. You might just have to move the one closest to the open window. Another thing you can do is to disconnect the wire that connects them all. Then open the window(s) and see which one sets itself off.
    If everything was always done "by the book"....the book would never change.

  10. #10
    Join Date
    Jun 2007
    Location
    Central, FL
    Posts
    871
    Well the name says it all detector of smoke, some detector use lighting across two points to tell if there is smoke. If there is a lot of pollen or if there is high humidity outside this might, interupt light beam going across those two points trigering the alarm. This happens alot with aircraft smoke detectors when it gets real humid in the cabin. Those very sensitive detectors are very price'y, I would stick with them if its not too much hassle!
    WARNING:IF YOU DON'T KNOW THEN DON'T DO, SO THOSE WHO KNOW WHAT YOU DIDN'T KNOW DON'T END UP UNDOING WHAT YOU DID SO IT COULD GET DONE RIGHT!

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