What is setting our smoke detector off?

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It happened again last night, second time this winter that the smoke detector went off in our bedroom in the middle of the night. Both me and the DW flew out of bed and ran sniffing in every bedroom to find a source of smoke---nothing. While the wife is jumping up and down on the bed trying to reach the crazy thing and disconnect it, I went downstairs to check the woodstove and still nothing. I went out the kitchen door and took a look at the barn, chicken house, everyone was fine. All I could think of that caused it, was that we like to sleep with the bedroom window wide open and it got down below 15 degrees last night. Could the cold, frigid air be making it malfunction? However, my wife is blaming it on the chili that I had in town yesterday!! She says that it is a proven fact that hot air rises. I agree that the chili in town is powerful stuff, but not that powerful!! She says if I set off the smoke alarm a third time that I'm out in the barn and can NEVER have chili again. What is it in those smoke detectors that can smell smoke? Can it detect other smells, like sulfur? Could she be right? Are any of you northern homesteader that sleep with the windows open having any trouble with your smoke detectors? Please help. Don

-- Don in the cold NW (PRGF1@aol.com), February 26, 2002

Answers

Temp variations of as little as + - 15 degrees can trigger a momentary isotope excitation which will trigger the alarm. Opening a non smoking oven or taking a hot shower in the proximity of a detector can be sufficient to trigger thye alarm circuitry. The open window could very well be the cause.

-- Jay Blair in N. AL (jayblair678@yahoo.com), February 26, 2002.

My wife says I can't cook chili in the house anymore and that her constant colds are due to the fact that my methane decreases her immunity to certain viruses. Who'd a thought!!! She is trying to devise a way to hook me up to the truck for free mileage. Oh well.

-- handy (nmhoofer@paulbunyan.net), February 26, 2002.

If you can get the cover off check and see if you're getting a dust build up. It was one of the most frequent causes of false alarms in the posts that I worked on back when I was still doing security work. Like the other poster said rapid temperature shifts can sometimes do it as well.

.........Alan.

-- Alan (athagan@atlantic.net), February 26, 2002.


Maybe this link on How Smoke Detectors Work, http://www.howstuffworks.com/smoke.htm will help answer your question.

-- BC (desertdweller44@yahoo.com), February 26, 2002.

At my house, it means dinner is ready.

Yes, cold air sets them off.

-- Laura (Ladybugwrangler@hotmail.com), February 26, 2002.



Sometimes they go off because the batt. is getting low. Just a thought

-- dale (dgarr@fidnet.com), February 26, 2002.

At my house, when the smoke detector went off, the usual response was "Mom's cooking again"! :-) Ionization detectors don't "smell" the air, but detect a change in current as particles (such as smoke) intercept the alpha particles emitted by the americium in the detector chamber. Unfortunately, small dust particles or water vapor will have the same effect, causing a false alarm. Try vacuuming the vents on the detector, but DON'T OPEN IT! Americium is nasty stuff, even the small amount contained in the chamber in the detector. If vacuuming doesn't help, just replace the detector, and dispose of it properly. The manufacturer should have a 1-800 number on the detector that gives disposal instructions.

-- Paul D. (pd-personal@msn.com), February 26, 2002.

Dale has a point - and chill temperatures such as you mentioned can really cut into the current a battery gives off, so it could be the effect of the temperature on a marginal battery rather than the temperature on the detector. Try putting in a fresh battery and see what happens - it's cheaper than sleeping in the barn, and less objectionable than giving up chili.

-- Don Armstrong (darmst@yahoo.com.au), February 27, 2002.

We also like to sleep with the window open .Maybe some smoke from your chimney got back into the house and set it off this has happend to us before. Indiana Country Friend Jack Bunyard

-- Jack Bunyard (bunyard@cnz.com), February 27, 2002.

Don't ya Hate that sound?!! I agree that it could be dirty. I manage property, over 75 condos and dirt is the most common cause of false alarms, next most common cause, is a small bug, spider or some other creepy crawly has walked across the inside. Remove it, check the battery if it has one, then vacuum all around the open area, or blow it out with an air compressor if you have one and reinstall it. If it continues, I say it has surpassed its' normal life span and needs to be replaced. C

-- Carole (carle@earthlink.net), February 27, 2002.


Don, Well first off how is the detector. Battery powered Smoke detectors have a finite life of about 5 years and should be replaced after that time. 120v power detectors have about 7 year life.

If the detector is going off it could be a build up of dust, Cold air can set it off if there is a quick change in air temp

-- Gary in Ohio (gws@columbus.rr.com), February 27, 2002.


My smoke detector was set of by a spider.

-- Kathy (catfish201@hotmail.com), February 27, 2002.

This was happening to us on really hot humid nights - we surmised it was the "hotness" in the air. Our detector was located right next to the opening from the attic for a whole house fan. In the winter, when the opening is boarded up, it never happens.

-- Christina (introibo2000@yahoo.com), February 27, 2002.

One of my detectors is in the hall outside the bathroom. If I take a reall HOT shower-------it goes off. I vote for the open window and the temperature factor.

-- Bonnie Norris (queqid@att.net), February 27, 2002.

All of these answers are good. The only thing I might add is to check and see if your smoke detector is also a detector for something else as well. I've seen multi-use detectors that go off in the presence of not only smoke, but also carbon monoxide, radon or other harmful things as well. You might want to check on that, too. I hope this helps.

-- Gary in Indiana (gk6854@aol.com), February 27, 2002.


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