Smoke alarm mystery. Ghosts?
July 28, 2016 7:58 AM   Subscribe

Replaced all old smoke detectors with new ones. The new ones seem to be malfunctioning as well. ??

My 10 year old smoke detectors started chirping all the time, despite replacing all the batteries. Prior to that, I had lived with them in my new-to-me house for 3 years with only the standard once-in-a-while chirping to replace a battery, after which I replaced said battery, and all was well.

I read that you're supposed to replace smoke detectors every 10 years anyhow, so I did some research, and replaced them all. The old ones were ionizing, and the new ones are photoelectric. While they make combo detectors, which I believe Consumer Reports recommended, the International Association of Firefighters recommends using only the photoelectric ones.

After replacing all of the units, and putting brand new batteries in them several weeks ago, last night at 4am they started going off like there was a fire, but stopped after 10 seconds. No sign of fire or smoke. I waited a minute to see if it would happen again, and it did, for about 5 seconds. It appears to have been a false alarm.

I couldn't tell which one was the culprit based on the led's, so I disabled all of them. Nobody else lives with me, so unless ghosts are burning stuff in the middle of the night that I can't smell or see, I got nuthin'.

(I also have completely separate carbon monoxide detectors in multiple rooms, all of which have detected nothing in the time I have lived there, but even if that was detected, I wouldn't think it would set off the photoelectric fire alarms).

Suggestions? Right now my plan is to return them if I can and get a different brand.
posted by bitterkitten to Home & Garden (11 answers total)
Oh and if it matters, these units are hardwired with the usual 9 volt battery backup.
posted by bitterkitten at 8:00 AM on July 28, 2016

Call the manufacturer. They will have a 1-800 number. I had a problem with smoke detectors I bought and called the company and they sent me 5 brand new detectors for free and didn't even want the old ones back. I realized after they sent but before they arrived that the mistake was mine (well and poor design on their part, so the test button wasn't the button shaped thing but a thing near it). I called them and explained and asked if they wanted me to send the new ones back when they came or what and they just let me keep them. The company was Kidde. I couldn't be happier with their customer service.

Incidentally, the page you linked to says that only photo-electric alarms should be MANDATED by city building codes, not that only those should be used. It says that dual alarms offer only marginal benefit (which I read as: "They offer benefit!" but I am a safety freak). The downside to ionization is more nuisance alarms, which means some people turn off their alarms, which is obviously dangerous, but if you put up dual alarms and don't turn them off, that is "marginally" safer than just a photoelectric-only alarm.
posted by If only I had a penguin... at 8:33 AM on July 28, 2016

We switched entirely back to ionizing after our less than a year old Kidde photoelectric ones started randomly going off. Kidde says something about some sort of annual maintenance cleaning, and how it must have been our fault, but we couldn't figure out how to return them to working status.
posted by straw at 8:34 AM on July 28, 2016

Could a fault in the wiring be causing the problem? I wonder if you hardwired these into the previous wiring then the wiring is all the two malfunctioning alarms have in common.
posted by cecic at 8:55 AM on July 28, 2016 [4 favorites]

I've had this problem and thus far all I've been able to blame it on is poor quality control on the devices. I'm not 100% sure that's right, but when I've continued to replace them, eventually I found a set that didn't do this (multiple units of the same model). Our house is big and has a ton of smoke alarms. I'd estimate that maybe 5% of the ones I've purchased over the past five years have had this problem. Maybe it's something with our wiring or environment, but replacing them with the exact same thing until I get one that works has solved the problem for me...
posted by primethyme at 9:23 AM on July 28, 2016

You say they're hardwired, but does that mean they're hardwired together? In other words, when one goes off, do they all go off? This is true for my smoke detectors, which is annoying because, as you point out, it can be hard to find the malfunctioning one. I eventually figured out that, after they go off, the light on the one that was triggered puts out a different pattern (i.e. a set of 3 blinks every 20 seconds instead of 1 blink every 60 seconds ... or something). You should be able to use that to find the one that triggered all of the others.

Why one of the detectors is giving you a false alarm is another question, but I agree with primethyme that it seems to me that smoke detector quality control has fallen off a cliff. I never remember false alarms from the smoke detectors in our house when I was growing up, but we've had intermittent (but persistent) problems with false alarms in the house I live in now as an adult. This is all anecdotal, but it really feels to me like smoke detectors these days are much more likely to malfunction and give false alarms than those in the past. Note that this even includes the one fancy Nest smoke detector we have (although the fact that that smoke detector went off at exactly midnight makes me wonder if it was a software bug).

I would strongly, strongly, strongly encourage you not to live in a house without functioning smoke detectors (says the guy who had a fire in his house ~3 years ago).
posted by Betelgeuse at 9:59 AM on July 28, 2016

The wiring is the same as before; I just used the same connectors that existed previously.

I don't know if "interconnected" means that they are hardwired together - but yes, when one goes off, they all go off.

I certainly do not plan to have no smoke detectors in my house. : ) I feel weird having them all still disconnected right now.

I checked for the led that is supposed to blink differently from the others, but since it was 4am and I was stumbling around just trying to turn them all off from a stepladder, perhaps I did not pay close enough attention. But I don't think I saw one that was the culprit.

So right now my plan is
a) try to return them to the store and get replacements if it hasn't been too long
b) if that fails, call the manufacturer and try to get replacements from them
c) if a) fails, I will in the meantime reconnect one detector at a time and see if that reveals anything., I realize there's still multiple potential points of failure, but I have to do sommmmmething. I guess I could get an electrician? to check the wiring. But is it likely that there's a wiring fault after replacement, vs the old ones were just getting old, and new ones are defective?
posted by bitterkitten at 11:50 AM on July 28, 2016

Spiders set them off sometimes, and I assume mainly the photoelectric ones, although recent research shows that the sticky bug-catching parts of a web are actually electrically conductive.
posted by jamjam at 12:29 PM on July 28, 2016

Yeah, I was going to suggest spiders. That's what turned out to be the problem when mine was going off for ten-second bursts several times a night.
posted by Catseye at 12:45 PM on July 28, 2016

Some of the models are more sensitive to small fluctuations in the electrical system and will go off with a minor spike. This could be as simple as the city electricity fluctuating or faulty wiring (older models were not as sensitive and could ignore the faulty wiring).

I had this problem a few years ago, after the new detectors I bought randomly started going off. I read reviews of the model on Amazon and noticed many others complaining. I ended up changing to a different model that was deemed less sensitive to such issues.

Meanwhile I also had an electrician look at the wiring (he was in the house already for another purpose) and it turned out that one of the smoke detectors was not properly grounded. One wire was not properly connected, and he speculated that this might be the reason for a more sensitive device to be triggered due to line fluctuations.

I don't know if it was true or not, but I haven't had any random alerts since. But it was not a controlled experiment, since I ended up fixing both the wiring and changing the model, so I don't know which action solved the problem.
posted by tuxster at 12:46 PM on July 28, 2016 [1 favorite]

This happened to me and it was caused by an arc fault in the electrical line.

I fixed it by repairing the line.

You can also move to using alarms that are battery only and are not interconnected.
posted by pdoege at 5:22 PM on July 28, 2016

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