Smoke detectors - false alarms (1 Viewer)

The past two nights, I have gotten false alarms from a smoke detector in my house. These detectors are ionizing detectors. They are all hard-wired to power and have the usual 9V battery backup.

When these false alarms happen, one detector (far away from my bedroom) goes off, but then a few seconds later all the others (including the one in my bedroom) join in. Because there are about 12 of them, it's next to impossible to figure out which one is responsible for the false alarms.

I tried cutting the power and taking out a battery to see if I could temporarily shut off the detectors, but the detector I tried must have had another backup power source as it started chirping (to indicate low / dead battery).

Any thoughts on what I should do to narrow down this problem? I'm planning to replace all the batteries tonight, but really won't be able to live with a false alarm jolting me awake every night. For safety and expense reasons I don't want to just tear out all the detectors, but I have to sleep somehow...

Do the false alarms happen at the same time each night? There are a number of things that can trigger them, including streams of ionized air (sometimes produced by air cleaners), dust, etc. I'm wondering if some timer event in or even outside your house is producing something that is triggering the alarms. Conversely maybe it is the asbsence of something that is the problem. A lack of air circulation (either because the heat/ac isn't running or the windows are closed, or because people aren't moving around in the affected area) could allow something to build up and then set the detector off sometime after everyone is in bed.
Just a few random thoughts.
Joe

The exact times of the false alarms vary. The first one was at about 2:20AM, the second one was at 12:20AM. This had only happened about once every two years until this week, and I've gotten them twice in a row.

There haven't been false alarms during waking hours yet.

Also, there should be nothing going on to generate dust, fumes, or smoke in the middle of the night.

Our smoke alarms will keep the red LED solid on the detector that went off first until we reset it. Possible you have this feature also? Just see if any have a solid LED on.

Two words.... BASEBALL BAT!!!!

Well, I went and got all new batteries for those smoke detectors this evening, and just finished putting them in. There are 10 in all - eight on the upper floor of my house, and two on the lower floor.

I installed new batteries in each detector, and also vacuumed around the intake vent and edge of each detector. I did the vacuuming because an article on-line said that ionizing detectors should be cleaned in this way periodically to avoid them becoming caked with dust and prone to false alarms.

I know the false alarm is being triggered on the upper floor. I could hear that the detector that initiated the alarm was far away, but then all others would join in "sympathy" a few seconds later.

So we'll see if this fixes the problem or not. If not, I may have to take the "baseball bat" approach ... and then put in 10 new detectors (hopefully optical ones this time) to replace them.

Everything I found on-line says a smoke detector should last at least 10 years before needing replacement. My house was completed in 2001, so these detectors are only 5 years old.

Just do what we did when the CO detector started going off all the time: take out the batteries.

Well, I got through last night without a false alarm. I put in the new batteries and vacuumed dust from around the smoke detectors. Hopefully this will do the trick.

Adam - Just taking out batteries or cutting power to them won't work as a short-term solution because they still chirp even with no power source. (They must have charged capacitors or another layer of battery backup that isn't user-controllable.)

Dennis - I looked at every detector when I changed batteries. There were none that had a red or flashing LED to indicate that they had gone off. All showed a solid green LED for "AC Power" (present). It's real annoying that all the detectors go off in sympathy but there is no way to isolate which one initiated the alarm.

Typically if they are all hardwired..when one goes off..they will all sound.

the one that sets the system off should show a flashing red light. Unfortunately you have to check each unit individually amidst all the cacophany to locate the offending unit. With the system functioning properly..they should all show green (power) and a red light should flash every once in a while as the system cycles through each unit checking for possible alarm triggers

So Colin, have you had any subsequent false alarms since the changes you made? I'm having the exact same symptoms with my smoke alarms at my house right now.

Hmm I know you vacuumed them try buying a can of air and blowing them out. The air can sometimes set off the smoke so beware. The one that goes off first could be the problem. Paint fumes can set them off too. Some detectors have heat detection built in too. It is a stretch but a sudden change in heat(temp) could be the problem. Lastly it may be just a bad detector.

All the smokes I service are photoelectric and low voltage. The alarm panels have a backup battery so there are none in the detector. electrical smokes could be different I'm not too sure.

Kent -

I haven't had any more false alarms since I replaced all the batteries and vacuumed on/around the detectors.

I think everything's OK for now, but if I get more false alarms I will try blowing them out with compressed air and/or finding the one that is flashing red amidst all the noise. But with 10 detectors making very loud and shrill alarms, that won't be a pleasant job...

just make sure you hit the ionization chamber/plates with the vacuum/compressed gas. it should be the metal cylinder looking thing with vents.

Dont EVER use smoke detector allarms with bateries! I had one and it just did not react whe I'd burnt a cake in the oven. I've found professional services
Home Security / Alarm Systems in USA - Free classified ads on Professional services
and had the battery allarm replaced with the plug in one and I feel safe now. this wasn't expensive and I can trust it!

Smoke alarms which take 9v batteries are fine, just replace the battery every 3-6 months per mfg. recommendations and test monthly. I wouldn't trust one which only plugs in because of a possible power failure during a fire. If it has a battery backup, it's ok.
Anyone remember listening to Dr. Drew and Adam Carolla on the Lovelines when someone would call in with a chirping smoke detector in the background?

The smoke detectors in a house we lived in about 10 years ago used to go off when the windows/doors were open and there was a lot of pollen in the air.

A friend of mine once rented a house with a smoke detector over the range directly below the vent-a-hood. It was awesome...All you had to do was turn on one of the gas burners and it would go off. Luckily it was a battery model so he took the battery out until he moved.

Clinton McClure said:

A friend of mine once rented a house with a smoke detector over the range directly below the vent-a-hood. It was awesome...All you had to do was turn on one of the gas burners and it would go off. Luckily it was a battery model so he took the battery out until he moved.

Click to expand...

Maybe the previous renter's wife was a really bad cook and the rest of the family wanted advance warning.......

Why are we replying to a three year old thread?

Anyway. Our smoke detectors are over sensitive. Our smoke det. is a good 20+ feet away from our oven, but the slightest bit of fume from the oven sets it off.

Is there any way to turn down the sensitivity on these things?