Last night, all of our smoke detectors went off. Not a constant tone – Just three short (but loud) chirps.
We did our evacuation thing and I checked around in all the locations and there was nothing. I decided if they went off again, I’d call 911 just in case. All of them seemed to be working. All had AC and the battery back-ups were good.
I’m wondering though, what happened to my smoke detectors? Could it have just been dust in the air? I had my power off briefly, earlier in the day, but this was about six hours later.
Any ideas why they might of briefly gone nuts (and scared the crap outta my kids) in the middle of the night?
Replies
Are these wired for sound together? That would explain them all going off. A short surge or the reverse, a spider perhaps, or the steak done could have caused them to sound initially. This has happened to us, not a good sleep that first nite.
Remodeling Contractor just outside the Glass City.
Quittin' Time
Edited 9/29/2004 8:19 pm ET by calvin
If it was only a single chirp it would indicate one, or more, of the batteries was dying.
While I cannot testify as to the meaning of three loud beeps and then nothing I can say that a lot of things can cause false alarms. Dust, mist from a shower, fog, smoke, insects, hairspray and talcum powder can cause false alarms. Usually these are more involved than just three beeps.
A SD that loses power will often make a plaintive beep and sometimes a slight dying sound that sounds like a tiny R2D2 giving up. On return of power, if the power blips on and then off and on again rapidly, a SD can be triggered.
A large surge, utility company switching or major mistake or, more commonly, lightning strikes, can damage a SD. Sometimes it fails right away. Other times it just gets flaky. Either way replacing it is the only practical cure.
If you have to replace a SD there are a couple of points to remember: Don't go cheap. No name dockside imports are not always reliable and if reliable now they seem, from personal experience, to be more prone to early failure, unexplained false alarms, and a greater sensitivity to surges. Remember that your, or your kids, lives depend on these units working. Buy a major brand and stick to the middle of the market for price.
Second point is SD type. There are two major types: ionization and photocell. Each has strengths and weaknesses.
The ionization units are the most common and generally the cheapest. This type are sensitive to the ionized products produced by open and rapidly burning flames. Ironically this type of smoke detector is actually not very good at detecting smoke. Only when the smoke gets fairly thick does this type activate. Problem is that most house fires, like from a dropped cigarette on bedding, smolder for a long time before actively flaming. By the time they do the amount of time remaining for people to get out is rather small.
The other type is the more expensive photocell units. These operate by checking how well light goes through the air. These are great at detecting smoke which can give a greater lead time and increased safety in a smoldering fire. This type is also more immune to false alarms from mist from a shower, typical benign garage smoke and minor cooking smoke.
Before you go out and toss your ionization units photocell units have a down side. If the fire is actively burning and producing little smoke a photocell unit may take a very long time to go off. This type of fire is rarer, but not unknown, in residential situations.
Your best bet is a mix of both types. If you don't have any photocell units, and given their relative cost this is quite likely, you might want to get a photocell unit to produce a mix.
There are dual detector SDs but these are several times more expensive than even the higher priced photocell units. This might be justified if you only had a very few SDs.
This is about the major reason I prefer the SDs to all be on a circuit by themselfs . Any problem can be traced quickly and found . They are known to give problems and I dont want them mixed on 11 other possible problems. Just my smoke to the discussion.
Tim Mooney
I was a fireman for 20 years (just retired) and there are a lot of reasons smoke detectors activate. From your description though it sounds like you had a brief power interruption. However, if you continue to have problems I would suggest replacing all the detectors if you have a hardwire system that is not connected to an alarm system. If the smoke detectors are part of an alarm system, call the alarm company, you might get by with a cleaning of the detectors.
Our smoke detector went off and we couldnt see smoke or smell it.
Several hours later my computer died. The power supply fan had burned out. When I got near the back of the computer I could smell the burned
motor. The SD did what it was designed to do, alert us to something burning. They seem to be really senstive.