Those of you who have read my book already know I harbor a certain amount of ill will towards smoke detectors. But last week one of my regular clients had an issue with their smoke detectors going off, and I learned a few new things that I thought I would share with you.
If a smoke detector is chirping, that either means the battery is dying (and obviously needs to be replaced), or maybe the main circuit coming from the panel has died, or the detector itself is dying. The point being, chirps are not the same as full blaring alarms. Chirps indicate loss of power, either from the panel, or far more likely, the battery is dying. If the thing is going off on a full blaring alarm, it’s usually something else. It is not likely that that is being caused by a dying battery.
This client’s detectors were blaring for ten minutes at a time. I replaced the batteries just because they were three years old and thus had to be replaced anyway, but the blaring, I went looking for another cause, and here is what I learned:
–Wired smoke detectors are usually installed with a communications wire running between them. (This wire makes it so if the basement alarm smells smoke, it will make the 3rd floor alarm go off, etc.) AND, the big point, there is a limit to how many detectors you can string together with that wire. The limit varies depending on who you ask, but at least one local fire department puts the limit at 7.
–Note, and this is not commonly known, it is NOT a good idea to mix and match different brands (e.g., Kidde vs First Alert) on the same communication wire/circuit.
— When you change the batteries (once a year is my own recommendation) it is a good idea to clean the units out with compressed air AND a vacuum. Smoke particles and spiders both look very much alike to a smoke detector. Clean them more often if the place is dirty, and cover the units if you are doing sanding etc.
This client had 10 detectors and 2 different brands going, so I took down the 3 inconsistently branded units (they were overkill anyway), I changed all the 3 year old batts, and I cleaned out the units with compressed air and a hand vacuum.
It’s been a month now. So far so good.
Note the makers all say the units are good for 10 years but I find that at year 7 at least one will go bad. When that one goes, I say, replace them all.
PS it’s also a good idea to combine photo electric detectors with a few ionization detectors if you can. Photo electric are better at detecting smoldering fires while ionization are better at detecting full on flames.
