Beeping smoke detector will not shut UP
July 24, 2010 8:55 PM   Subscribe

Any ideas about how to fix a chirping smoke detector before I burn my goddamned house down myself just to SHUT IT UP??

About an hour ago the smoke detector in my house started emitting intermittent ear-splitting beeps at roughly 30-60 second intervals. This detector is wired into the home's electrical system.

I've tried blowing vigorously into it to dislodge any dust, and then reconnecting and pushing reset button. I also have tried to open up the detector part itself to see if there's a backup battery that needs replacing, but it feels like I'm going to have to break it to get it open.

Nothing helps, and in fact something in the ceiling is still beeping even though I've disconnected the smoke detector and all its attached wiring, and also shut off the circuit breaker to that part of the house.

I have not been cooking anything all day, nor doing anything else that would produce smoke or dust.

FWIW, the detector is a Kidde model 1235. I found the manual on line, but it doesn't have anything particularly useful to say.

posted by Kat Allison to Home & Garden (26 answers total) 2 users marked this as a favorite
Low battery.
posted by Aquaman at 8:59 PM on July 24, 2010 [6 favorites]

What do you mean that something in the ceiling is beeping? You disconnected the smoke detector, held it in your hand, and still heard beeping from the ceiling?
posted by found missing at 9:01 PM on July 24, 2010

Beeping every 30-60 seconds is indeed the sign of a failed battery. I checked the manual for the Kidde 1235 and it takes a 9V backup battery. The manual has a picture of the battery installation.
posted by kindall at 9:01 PM on July 24, 2010

Low battery
posted by KokuRyu at 9:03 PM on July 24, 2010

The PDF that I'm looking specifically says that the model 1235 does not have a battery backup.
posted by found missing at 9:04 PM on July 24, 2010

"When mixing models which have battery backup (1275, 1275H, 1285, PE 120, HD135F) with models without battery backup, (1235, 120X, SL177I) be advised that the models without battery backup will not respond during an AC power failure."
posted by found missing at 9:05 PM on July 24, 2010

posted by found missing at 9:06 PM on July 24, 2010

Yeah, I'm confused, because the chirping sound you mention sounds like a standard low-battery warning, but the PDF manual that found missing and I are probably both looking at indicates that model 1235 has no battery. Which manual is kindall looking at?
posted by Orinda at 9:08 PM on July 24, 2010

With all deference to the "low battery" experts, one possibility is that it is beeping precisely because you disconnected its hardwired power supply. Try installing it, making sure the breaker is on and that power is reaching the unit.
posted by found missing at 9:08 PM on July 24, 2010

Is the "beeping" in the ceiling the same sound as the "chirping" you were hearing from the detector earlier?
posted by Orinda at 9:10 PM on July 24, 2010

posted by found missing at 9:15 PM on July 24, 2010

Random theory: some other smoke detector in the house has a low backup battery, and is chirping, and this makes the whole smoke-detector network chirp? (weird design if so.)
posted by hattifattener at 9:20 PM on July 24, 2010

Do you have other things like a carbon monoxide detector installed that might be beeping? Any other devices that might have an alarm on them?

Also, in a lot of places if you call your local fire department and explain what's going on, they will come out and take a look at it for free. I'm not sure that all of them do this, but over here they'll do it. Maybe that's just a small town thing though.
posted by howrobotsaremade at 9:21 PM on July 24, 2010

I had this same problem. I also thought it was the smoke detector, which is wired into the ceiling. It was actually my carbon monoxide detector that was chirping, which had low batteries. So maybe it's your CO detector!
posted by foxjacket at 9:26 PM on July 24, 2010

Sorry about not responding earlier -- I shut down the computer so I could turn off the entire power supply to the house and see if that would stop the beeping. Which it did not. However, about ten minutes later, it *did* stop, for no apparent reason. I was on the phone at the time with a friend whose counsel was the same as howrobotsaremade (call fire dept.), and I will do that if the beeping resumes. I did stick my head up in the attic to verify there's nothing burning up there.

Just to catch up -- yeah, it doesn't appear that this specific model has a battery backup. I should clarify that the "beeping" and "chirping" are the same noise -- that sharp, short sort of warning beep that detectors typically give off when batteries are low.

And, most creepily, it did indeed continue with the beep/chirp even after the detector was disconnected, the wiring was disconnected, and the power was shut off. I have NO idea. But I have an electrician coming over tomorrow to take a look-see. I guess it could be a CO detector, but there's no outward sign of one ...

Thanks, everyone, for your helpful ideas and suggestions!
posted by Kat Allison at 9:41 PM on July 24, 2010

I have hard wired smoke detectors. They do not last forever. I have had the same issue. You remove it by twisting it and there should be a male-female plug. Unplug that and see if it is still chirping. Sometimes the sensor pad simply "goes bad" (the technical term my electrician used). I went to Home Depot and purchased a new one which I was able to install (Plug and twist). Chirping gone. I have had ones that chirp even when disconnected with the backup battery DISCONNECTED. I am willing to bet big money that the chirping starts up again within 24 hours.
posted by JohnnyGunn at 9:59 PM on July 24, 2010

JohnnyGunn -- yeah, I twisted off and removed the detector part itself (the disc-shaped thingie), and unplugged the plug. It still chirped. I disconnected the plug fixture from the actual wiring that goes into the ceiling -- still chirped.

I don't know why it's now stopped (given that I don't know why it started in the first place), but I tell you, if it starts again tonight, I'm going to thump my head against the wall a few times.

The current plan is to have an electrician come by and replace the current setup with a battery-powered one, on the grounds that it should be relatively easy to replace a freakin' battery, as distinct from messing around with hard-wired arrangements.

(Dear GOD, there are times I miss being a renter.....)
posted by Kat Allison at 10:08 PM on July 24, 2010

Smoke detectors do have a finite lifespan, especially the ionization-chamber type (which the Kidde 1235 is). I think they generally last about ten years, after which some models will beep to let you know you should replace them.
posted by hattifattener at 10:25 PM on July 24, 2010

Your unit has no backup battery. Because of this, a power failure would leave the unit without power to notify you that it had no power. So, the unit has a capacitor that holds a certain amount of power, enough to keep the power failure beeping going for a finite amount of time. Once that amount of time has passed, the chirping stops.

However, the chirping is also used to notify you that the detector (from age or defect) needs repair or replacement. So if it needs attention, the chirping starts.

So, here's what happened: the unit started chirping to tell you it needed attention. When you finally disconnected the power, it continued to chirp, but this time to tell you the power was disconnected. When the capacitor ran out, so did the chirp.

Chuck it and get a new one.
posted by davejay at 11:32 PM on July 24, 2010 [2 favorites]

I had a couple of units (with battery back up) that were twitchy. They would just chirp for a few hours (even with a new battery) then stop. I replaced the detector. It was that easy.
posted by plinth at 3:22 AM on July 25, 2010

Smoke detectors use radioactive (alpha) decay to detect the presence of smoke. The radioactive source inside will gradually decay, and after approximately 10 years will need to be replaced. Because radioactive decay is random what you may have been hearing was a warning that will come and go with the random nature of the decay as the source "fails".
posted by alby at 6:39 AM on July 25, 2010

Assuming you do get a new one, you need to either exchange the old one if the store will take it back, or take it to a hazardous materials pickup site. Do not throw it in the trash; it has a small amount of radioactive element in it.
posted by Slinga at 9:32 AM on July 25, 2010

Smoke detectors use radioactive (alpha) decay to detect the presence of smoke. The radioactive source inside will gradually decay, and after approximately 10 years will need to be replaced.

Most smoke detectors use Americium-241 as a radiation source, which has a half-life of 432 years. So, it's not likely that the radiation source is the problem. It's more likely that one or more of the electronic components have failed.
posted by chrisamiller at 9:33 AM on July 25, 2010

FYI, we've been replacing all the detectors in our (new to us) house a couple at at time. For like $4 more than a regular detector, you can get the ones w/ the 10-year battery (normally you change the 9v annually) so basically after 10 years you just chuck the device. No need to hard wire, although networked ones are nice for early detection. For like an extra $8 you can get wireless ones that talk, but I have not used those.

I think we're paying like $12 for a 10-year batteried-hushable detector. Soooo much better than what was in place when we got the house.
posted by TomMelee at 11:03 AM on July 26, 2010

I have had ones that chirp even when disconnected with the backup battery DISCONNECTED.

They do have a capacitor in there somewhere. Hit the Test button and that should drain the cap pretty quickly.
posted by kindall at 3:10 PM on July 27, 2010

Just to bring closure--closure of a profoundly embarrassing nature, I must add--to this saga: the chirping noise started again the next evening, originating (as far as I could tell) in the ceiling area from which I had removed the detector; I called the fire dept.; they sent out a very, very tall young man who looked the situation over, stuck his head into the adjacent bedroom, and discovered ....

Yeah. There was another smoke detector, stuck up on the wall right above the door, half-hidden by the door molding, which I had somehow completely overlooked. A battery-operated smoke detector. Whose battery was going bad. And which was close enough to the site of the original smoke detector that it was hard to tell the noise was coming from a different location.

So, problem solved, and the takeaway for those of you reading along at home: in 99.5% of hardware/tech glitches where you're waving your arms and shrieking "I tried EVERYTHING!!" the problem is with the diagnosis, not the solution. Thanks again to everyone who commented and advised!
posted by Kat Allison at 3:54 PM on July 28, 2010

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